Photon-Counting CT Clinical Case Reports - Radiology Edition

Clinical case reports – Radiology edition Photon-counting CT – impacting clinical outcomes with NAEOTOM Alpha® siemens-healthineers.com/naeotom-alpha SIEMENS Healthineers Contents CHA Oncology Pulmonology 04 Severe ureteral obstruction secondary to 27 Follow-up of an acute pulmonary embolism an upper urinary tract urothelial carcinoma in an obese patient with an unknown patent foramen ovale 06 Atypical pancreatic neuroendocrine tumor secondary to metastatic renal cell carcinoma 30 Chronic thromboembolic pulmonary hypertension diagnosed after COVID-19 08 A small pulmonary nodule in an obese patient 33 Severe emphysema treated with endobronchial valves 10 Metastatic pulmonary adenocarcinoma – complicated by PE? Neurology 13 Pancreatic cystic neoplasm – malignant or benign? 36 Cerebrospinal fluid-venous fistula detected 16 Inside an incidental solid renal mass in a patient with a long history of headaches 19 Two small non-invasive papillary urothelial carcinomas in the left renal pelvis and ureter 22 Pancreatic insulinoma in a patient with a history of hypoglycemia 24 A well-differentiated, invasive ductal adenocarcinoma in the pancreatic body 2 Photon-counting CT case reports Contents Otology Pediatrics 38 Stapes prosthesis dislocation 54 Pediatric ureterocele complicated by urolithiasis 40 Congenital cholesteatoma Vascular Gastroenterology 56 Macromastia with severe ptosis 42 Small bowel infarction secondary to an acquired diaphragmatic hernia Orthopedics 44 Scaphoid fracture only seen in CT 46 Osteochondritis dissecans of the capitellum 48 FOOSH injury with screw fixation of the scaphoid 50 Non-osseous subtalar coalition 52 Pseudarthrosis revision of a comminuted tibia fracture – consolidated? Photon-counting CT case reports 3 Case report · Oncology Severe ureteral obstruction secondary to an upper urinary tract urothelial carcinoma Jan Baxa, MD, Ph.D.; Jiří Ferda, MD, Ph.D. Department of Imaging Methods, University Hospital Pilsen and Medical Faculty of Charles University, Pilsen, Czech Republic History 1a 1b 1 Axial images A 55-year-old female patient, show a dilated suffering from hematuria for the left renal pelvis in a standard past few weeks, came to the hos- image (Fig. 1a) pital for a check-up. An ultrasound with hyperdense examination revealed a dilatation blood content of the left renal calyces and pelvis, identified in however, could not report upon a VNC image (Fig. 2b, arrow). the cause. A urine cytology analysis did not prove urothelial carcinoma (UC), and the patient reported no other significant symptoms A contrast CT examination was A delayed scan, performed 4 hours bleeding to the renal pelvis can requested for further evaluation. later, showed no excretion of con- also be determined. Both lesions, trast agent (Fig. 4). Subsequently, especially the tiny discrete infiltra- Diagnosis an ureteroscopy was performed and tion at the pelviureteric junction the histological results confirmed causing severe ureteral obstruction, CT images, with spectral recon- the diagnosis of an UC. The patient are not visible and could have been structions, showed dilated left was then scheduled for surgery. missed in standard CT images. How- renal calyces and pelvis which were ever, they are significantly enhanced hyperdense in the Virtual Non- Comments and clearly visible in the Mono- Contrast (VNC) images, suggesting energetic Plus images displayed at blood content (Fig. 1). Two small Urothelial tumors affecting the up- 45 keV as well as in the iodine maps lesions, measuring 6 x 5 mm in per urinary tract are relatively rare, fused with VNC images. the central part of the renal pelvis accounting for only approximately and 4 x 5 mm at the pelviureteric 1% of all urothelial tumors. The This case is performed with junction, were visualized in the most common histological type is NAEOTOM Alpha®, a newly devel- Monoenergenetic Plus images UC found in 90% of the cases. It can oped CT scanner with photon-count- displayed at 45 keV, as well as in cause ureteral obstruction leading ing detectors. It provides energy- the iodine maps fused with VNC. to hydronephrosis, infection or resolved CT data with a very high Both lesions were not visible in spontaneous rupture. Traditionally, spatial resolution, without electronic standard CT images (Monoenegetic a CT evaluation for hematuria with noise. [2] One of the key benefits images displayed at 70 keV, corre- suspected UC would require both of photon-counting CT is the availa - sponding to images acquired at non-contrast and contrast scans. [1] bility of spectral CT data in any scan, 120 kV), presumably due to their In this case, only one contrast scan without having to consider and small size and being obscured is performed, acquiring spectral CT decide on the type of the scan by the hyperdense blood content. data which can be used for further before data acquisition or to recall The small lesion at the pelviureteric spectral reconstructions, such as the patient after scanning. This junction could most probably be VNC, Monoenergetic Plus and iodine has a major impact on improving considered as a discrete tumor infil- maps. The blood content in the clinical routine practice and helping tration and the cause of a severe renal pelvis is identified in the VNC the physicians make confident ureteral obstruction (Figs. 2 & 3). images and the proportion of the diagnoses. 4 Photon-counting CT case reports Oncology · Case report 2a 3a 4 4 A VRT image from a delayed scan (4 hours later) shows no excretion of the left kidney due to a severe obstruction at the pelviureteric junction. 2b 3b Examination Protocol Scanner NAEOTOM Alpha Scan area Abdomen/Pelvis Scan mode QuantumPlus Scan length 209 mm Scan direction Cranio-caudal Scan time 2.3 s 2c 3c Tube voltage 120 kV Effective mAs 105 mAs Dose modulation CARE Dose4D CTDIvol 8.25 mGy DLP 369 mGy*cm Rotation time 0.5 s Pitch 0.8 2 Coronal images show a small lesion in the central part of the Slice collimation 144 x 0.4 mm left renal pelvis, unidentifiable in a standard image (Fig. 2a), but significantly enhanced and clearly visible in a Mono- Slice width 0.4 mm energetic Plus image displayed at 45 keV (Fig. 2b, arrow) Reconstruction 0.2 mm and an iodine map fused with VNC (Fig. 2c, arrow). increment 3 Oblique images show a small lesion in the central part of Reconstruction kernel Br36, QIR 3 the left renal pelvis (dotted arrows), as well as a tiny lesion at the pelviureteric junction (arrows), both invisible in a Spectral Reconstruction VNC, Monoenergetic Plus, standard image (Fig. 3a), but clearly seen in a Monoenergetic iodine map Plus image displayed at 45 keV (Fig. 3b) and an iodine map fused with VNC (Fig. 3c). Contrast 370 mg/mL Volume 1st bolus (70 mL + 40 mL saline) 20 s pause – – References 2nd bolus (30 mL + 20 mL saline) [1] Abouelkheir RT, Elawdy MM, Taha DE, El-Hamid MA, Osman Y, El-Diasty T. The accuracy of computed tomography in the diagnosis Flow rate 4 mL/s of upper urinary tract urothelial carcinoma in correlation with Start delay Bolus tracking triggered in the the final histopathology: A retrospective study in 275 patients at 2nd bolus with 100 HU in the a Tertiary Urology Institute. Urol Ann 2021;13:356-61. distal descending aorta + 5 s [2] Thomas Flohr, Martin Petersilka, Andre Henning, Stefan Ulzheimer, Jiří Ferda, Bernhard Schmidt. Photon-counting CT review. Physica Medica 79 (2020) 126–136. Note: A so-called “Split bolus” technique was applied, acquiring portal/venous phase with the first bolus, and arterial phase with the second bolus, scanning The statements by customers of Siemens Healthineers described herein only once. are based on results that were achieved in the customer’s unique setting. Because there is no “typical” hospital and many variables exist (e.g., hospital size, case mix, level of IT and/or automation adoption) there The products/features (mentioned herein) are not commercially available in all can be no guarantee that other customers will achieve the same results. countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 5 Case report · Oncology Atypical pancreatic neuroendocrine tumor secondary to metastatic renal cell carcinoma Bettina K. Budai1, Márton Benke2, Ákos Szücs2, Pál N. Kaposi1, Attila Szijártó2, Pál Maurovich-Horvat1, Ibolyka Dudás1 1 Department of Radiology, Medical Imaging Centre, Semmelweis University, Budapest, Hungary 2 Department of Surgery, Transplantation and Gastroenterology, Semmelweis University, Budapest, Hungary History A 64-year-old female patient had accounting for the possibility of an improved spatial resolution, without undergone nephrectomy twelve years atypical pancreatic neuroendocrine electronic noise. [3] Image acquisition ago due to T2 N0 M0 clear cell renal tumor (pNET), or an atypical ccRCC with a thin slice collimation of 144 × cell carcinoma (ccRCC). One year metastasis, or an adenocarcinoma. 0.4 mm, and image reconstruction later, a single lymph node metastasis The patient was then referred to with a sharper kernel of Br44 are rou- was found, which triggered systemic endoscopic ultrasound (EUS) with tinely applied for abdominal imaging, therapy with sunitinib over two years, biopsy. Histological analysis resulted improving image sharpness while resulting in compete response. How- in a pNET and the patient was sched- obtaining full spectral information. ever, the therapy was re-started six uled for surgery. A refined iterative reconstruction years later after an adrenal metastasis technique (Quantum Iterative Recon- occured which was treated surgically Comments struction, QIR) is used to efficiently as well. On a recent follow-up CT, reduce image noise in these thin another novel lesion was visualized Pancreatic head masses have a broad slices, without negatively affecting in the pancreatic head. This partially variety of conditions. Typically, image sharpness or image noise obstructed the portal vein, raising pNETs and ccRCC metastases are well- texture. Owing to the availability of the concern of either tumor invasion circumscribed, hypervascular lesions, the spectral data and reduced image or thrombus formation. For further best seen on (early) arterial phase noise, virtual-monoenergetic images assessment and surgical planning, and cause no significant biliary or can be routinely displayed at lower a three-phase (arterial, pancreatic, pancreatic duct dilatation. However, keV levels for enhanced soft tissue venous) contrast-enhanced CT scan although rare, atypical forms of contrast, and iodine maps can be re- was requested and performed on both tumors exist, which appear as constructed for improved visualization our newly installed photon-counting hypodense masses, mimicking of boundaries differentiating the CT (PCCT). pancreatic adenocarcinoma. [1,2] tumor from the pancreas parenchyma For differential diagnosis, the atypical as well as from the portal vein. These Diagnosis form of the tumors and the medical thin slices can also be used to gener- history of the patient must be con- ate a photo-realistic three-dimension- CT images of the native scan showed sidered. Tumor resectability needs to al visualization of the anatomical an enlarged, isodense pancreatic be carefully assessed prior to surgery, details using cinematic volume ren- head, in which a hypo-attenuating, where signs of tumor invasion into dering technique (cVRT), facilitating well circumscribed mass measuring adjacent vessels play the crucial role. the communication between the 4.5 x 4.0 x 6.7 cm was depicted in In order to deliver a diagnosis most radiologists and the surgeons. As the virtual-monoenergetic images precise, high image sharpness and shown in this very rare case – an displayed at 65 keV in the pancreatic low image noise are mandatory, atypical pNET as a second primary phase. The mass was iso-attenuating which impose technical difficulties tumor in a patient with a metastatic in both the arterial and venous phas- and challenges to conventional CT. ccRCC – the combination of increased es, showing delayed enhancement. image sharpness and contrast with It extended into the portal vein, This case is performed on a NAEOTOM reduced image noise offered by causing a partial dislocation and Alpha®, a newly developed Dual PCCT improves anatomic conspicuity, obstruction without signs of invasion. Source CT scanner with photon- enhancing the confidence of the No biliary or pancreatic duct obstru- counting detectors (QuantaMax®), radiologists when making a differen- tion was present. CT findings suggest- providing energy-resolved CT data tial diagnosis and assessing tumor ed a surgically resectable tumor, with inherent spectral information at resectability. 6 Photon-counting CT case reports Oncology · Case report 2a 1a 1b Examination Protocol Scanner NAEOTOM Alpha Scan area Abdomen Scan mode QuantumPlus (native/ arterial/pancreatic/venous) Scan length 216 / 216 / 116 / 426 mm 1 A comparison, between an axial image acquired on PCCT (Fig. 1a) with Scan direction Cranio-caudal an axial image acquired on a conventional CT 4 months earlier (Fig. 1b), shows a clearer boundary between the lesion (arrows) and the portal Scan time 2.2 / 2.2 / 1.1 / 4.5 s vein in the former. Tube voltage 120 kV Effective mAs 143 / 163 / 123 / 124 mAs 2a 2b Dose modulation CARE Dose4D CTDIvol 11.2 / 12.8 / 9.7 / 9.8 mGy DLP 284/323/145/454 mGy*cm Rotation time 0.5 s Pitch 0.8 Slice collimation 144 × 0.4 mm 2 Coronal views of a MPR (Fig. 2a) and an iodine map (Fig. 2b) show the hypodense pancreatic head lesion, extending into the portal Slice width 0.4, 1.0, 2.0, 3.0 mm vein (arrows) without signs of invasion. Reconstruction 0.4, 0.5, 1.5, 3.0 mm increment 3a Reconstruction Br44, Qr40 kernel Spectral Monoenergetic Plus, reconstruction iodine maps Contrast 370 mg/mL Volume 78 mL + 40 mL saline Flow rate 3 mL/s Start delay Arterial phase: 23 s Pancreatic phase: 45 s 3b Venous phase: 75 s References [1] Shankar PR, et al. Hypervascular pancreatic “lesions”: a pattern-based approach to differentiation. Abdomi- nal radiology (New York). 2018; 43(4):1013-1028. [2] Coakley FV, et al. Pancreatic imaging mimics: part 1, imaging mimics of pancreatic adenocarcinoma. 199(2):301-308. 3 cVRT images show the hypodense pancreatic head lesion, extending into the portal vein without signs of invasion, and its surrounding [3] Thomas Flohr, et al. Photon-counting CT review. structures in three dimensions. Physica Medica 79 (2020)126–136. The statements by customers of Siemens Healthineers described herein are based on results that were achieved in the customer’s unique setting. Because there is no “typical” hospital The products/features (mentioned herein) are not commercially and many variables exist (e.g., hospital size, case mix, level of IT and/or automation available in all countries. Their future availability cannot be adoption) there can be no guarantee that other customers will achieve the same results. guaranteed. Photon-counting CT case reports 7 Case report · Oncology A small pulmonary nodule in an obese patient Prof. Anders Persson, MD, Ph.D.1; Lilian Henriksson, M.Sc.2,3 1 Center for Medical Image Science and Visualization (CMIV), Medical Faculty/Radiology, Linköping University, Linköping, Sweden 2 Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden 3 Department of Radiology, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden History 1a 1b A 60-year-old female patient with severe obesity (300 kg body weight) was admitted to the hospital due to widespread erysipelas in her left leg, sepsis with streptococcus and acute renal failure. Her medical history included Levaxin-substituted hypo- thyroidism and psoriasis. After treatment, her renal function was normalized with a serum creatinine 1c 1d value of 34 µmol/L, and she was generally feeling better. A lung X-ray was performed and revealed a round, well-defined lesion, measuring 23 mm in diameter, at the level of the right pulmonary hilus with an unclear nature. Contrast enhanced chest and abdominal CTs were requested for further investigation. 1 Diagnosis Axial images (0.5 mm) show a small, well-defined round lesion, without contrast enhancement, in the right middle lobe (arrows). A segmental atelectasis is seen in CT images showed a small, well- the right lower lobe (dotted arrows). defined round lesion, 17 mm in diameter and without contrast scattering, anatomical conspicuity flux and tube output is lowering enhancement in the right middle in pertinent pathologic conditions the pitch and increasing the rotation lobe. Further, there was a segmental is correspondingly decreased. This time; these measures, however, slow atelectasis of the right lower lobe. causes difficulties in image inter- down the scan speed and increase No signs of bronchial obstruction pretation and may lead to repeated breath-hold time with inherently were evident. With the side finding radiological or further clinical increased presence of motion arti- of a single gallbladder stone, the examinations, resulting in higher facts. Hence, despite all the advances rest of the scan was unremarkable. cumulative radiation dose and made in conventional detector CT The appearance of the lung lesion increased costs. If only considering in recent years, obese patients are was regarded as benign. the statistical noise of X-rays, the still a difficult target group for CT. dose needs to be quadrupled to halve the image noise. The situation This case was performed on a Comments is even worse with the presence of NAEOTOM Alpha®, a newly devel- substantial electronic noise. There- oped dual source CT scanner with The prevalence of obese and morbidly fore, image noise reduction comes photon-counting detectors (Quanta- obese patients increases. [1] As image at the cost of increased radiation Max®), providing energy-resolved CT noise increases exponentially with dose which requires higher power data without electronic noise. [2] increasing patient diameter due to output of the X-ray tube. The Electronic noise is eliminated by set- greater photon attenuation and classical way of maximizing X-ray ting up a predefined digital threshold 8 Photon-counting CT case reports Oncology · Case report Examination Protocol 2a 2c Scanner NAEOTOM Alpha Scan area Trunk Scan mode QuantumPlus Scan length 719 mm Scan direction Cranio-caudal 2d Scan time 10 s Tube voltage 120 kV Effective mAs 262 mAs Dose modulation CARE Dose4D CTDIvol 20.6 mGy DLP 1,540 mGy*cm 2b Rotation time 0.5 s Pitch 0.6 Slice collimation 144 x 0.4 mm Slice width 0.8 mm Reconstruction 0.5 mm increment Reconstruction Qr40 2 Coronal MPR images (Figs. 2a & 2b, 0.5 mm) show a small, well-defined round lesion, kernel without enhancement, in the right middle lobe (arrows). A centimeter-sized round gallstone with a hyperdense ring is seen in an axial image (Fig. 2c, dotted arrow). A cVRT image (Fig. 2d) reconstructed with 0.5 mm slices show both the lung lesion Contrast 350 mg/mL (arrow) and the gallstone (dotted arrow) in three dimensions. Volume 113 mL + 30 mL saline Flow rate 3.8 mL/s Start delay 70 s for counting X-ray photons far above for further image noise reduction. References the electronic noise floor, leading All of these improvements contribute [1] D. M. Fursevich, et al. Bariatric CT to less image noise and, potentially, to the reduction of image noise as Imaging: Challenges and Solutions. to the reduction of radiation dose. well as radiation dose. For example RadioGraphics 2016; 36:0000–0000. As electronic noise is dominant at even slices as thin as 0.5 mm [2] Thomas Flohr, et al. Photon-counting – low X-ray flux at the detector, such as can be used for three-dimensional CT review. Physica Medica 79 (2020) in the case of a low dose or bariatric demonstration with great image 126–136. CT scan, its absence has a particular details using cinematic volume impact on the improvement of the rendering technique (cVRT). As image quality. Another important presented in this case, although the advancement is the higher contrast- patient weighs 300 kg, the CT scan The statements by customers of Siemens to-noise ratio (CNR) in iodine contrast Healthineers described herein are based on required only 314 mA – less than results that were achieved in the customer’s enhanced CT scans, due to the one-third of the maximum power unique setting. Because there is no “typical” absence of down-weighting of lower of a single X-ray tube (1,000 mA at hospital and many variables exist (e.g., hospital energy X-ray photons. In the image 120 kV) – achieving optimal image size, case mix, level of IT and/or automation adoption) there can be no guarantee that reconstruction process, a model quality that helped the physicians other customers will achieve the same results. based iterative reconstruction make a confident diagnosis. approach – Quantum Iterative The products/features (mentioned herein) are not commercially available in all countries. Reconstruction (QIR) – is applied Their future availability cannot be guaranteed. Photon-counting CT case reports 9 Case report · Oncology Metastatic pulmonary adenocarcinoma – complicated by PE? Prof. Martine Rémy-Jardin, MD1, Ph.D.; Prof. Jacques Rémy, MD2 1 Department of Thoracic Imaging, University Centre of Lille, France 2 Department of Radiology, Hospital Center of Valenciennes, France History A 51-year-old male patient, suffering Based upon the CT findings, a satis- from pulmonary adenocarcinoma factory response to the initiated 1a with lymphangitic carcinomatosis, treatment was anticipated, leading [1] ROI Circle bone and neuro metastases, had to the upholding of the proposed Mean/SO: 193 H JAS HU undergone chemotherapy as well immuno-chemotherapy. as immunotherapy. A contrast chest and abdomen CT examination was requested for a follow-up evaluation Comments of treatment response. Non-small cell lung cancer (NSCLC) is the most common type, represent- Diagnosis ing 84% of all lung cancers. Among 1b its various histotypes, adenocarcino- Virtual monoenergetic CT images, mas are most predominant, account- [1] ROL Circle displayed at 60 keV, revealed a ing for approximately 40%. [1] Lung VearvSD 248 HUNS HU partial regression of several nodules cancer staging and follow-up evalua- and areas of consolidation, also of tion on treatment response are the lymphangitic carcinomatosis. commonly performed with a con- The hilar and mediastinal adeno- trast-enhanced CT. An optimal scan pathy had decreased in size. The protocol has been broadly investi- evolution of the bone metastases gated and recent literature has in the sternum and in the 7th left- suggested that imaging during the 1c sided rib was also seen. The azygos venous phase can aid in nodal, and hemiazygos veins were dilated. pleural, and parenchymal assess- [1] ROI Circle MesW/SD 481 H0 03 HO O A slight blunting of the right costo- ment. [1, 2] At this phase, tumoral phrenic angle was noticed, indicating structures, e.g., necrotic areas, as a small, newly formed pleural effu- well as lesions at the level of the sion. A thickening of the bilateral pleura and pericardium, are better adrenal glands and of two small enhanced and visualized. The con- hypodense lesions in the liver were trast material in the superior vena visualized, suspicious of metastases. cava (SVC) and brachiocephalic veins 1 Axial images displayed at 70 keV For the evaluation of the pulmonary is diluted due to recirculation, and no (Fig. 1a), 60 keV (Fig. 1b) and 40 keV arteries (PA), image display was longer causes streak artifacts. This (Fig. 1c) show a difference in the switched from 60 keV to 40 keV. improves visualization and character- attenuation of the MPA (193 HU, This increased the attenuation in ization of the lymph nodes. However, 248 HU and 481 HU). The contrast the main PA (MPA) from 248 HU a potential drawback of the venous- material in the SVC is homogeneous and causes no streak artifacts. to 481 HU which was sufficient for phase CT is the potential reduction A central venous catheter (arrow) the visualization of endo- and peri- in the identification of incidental PE, is also seen. vascular abnormalities. There were which is not an uncommon finding no signs of incidental pulmonary in this patient demographic – these treatment. [2] With the introduction embolism (PE) seen, and the lung patients are at increased risk of of Dual Energy CT imaging, studies perfused blood volume (Lung PBV*) thromboembolic disease, and detec- have been explored and shown images showed no perfusion defect. tion would allow for appropriate that virtual monoenergetic images 10 Photon-counting CT case reports Oncology · Case report 2a 2b 2 A coronal image displayed at 70 keV (Fig. 2a) shows an insufficient and slightly heterogeneous attenuation in the posterior basal segmental PA (arrow). The attenuation is increased in the image displayed at 60 keV (Fig. 2b) and is clearly restored in the image displayed at 40 keV (Fig. 2c), confirming an absence of PE. A Lung PBV image (Fig. 2d) shows a homo- geneous iodine distribution in the lungs without perfusion defect. A slight blunting of the right costo- phrenic angle is seen, indicating a small pleural effusion. The azygos 2c 2d and hemiazygos veins are dilated. 3a 3b displayed at lower keV levels can, to obtain an acceptable compromise increase iodine attenuation and for contrast-enhanced soft tissue improve diagnostic image quality for structures as well as vasculatures. detecting PE as an incidental finding When necessary, images can be in portal-venous phase CT scans. [3] displayed at an even lower energy level, e.g., 40 keV, to further increase This case is performed on NAEOTOM the iodine enhancement in the PAs Alpha®, a newly developed Dual for a more confident PE evaluation. 3c Source CT scanner with photon- The spectral data can also be used counting detectors (QuantaMax®), to create iodine maps (Lung PBV), providing energy-resolved CT data resulting in a simultaneous assess- with inherent spectral information ment of the pulmonary vasculature and improved tissue contrasts, as well as the analysis of the without electronic noise. [4] The parenchymal iodine distribution. spectral data is available in all The combination of the absence of routine scans allowing for an easy electronic noise and the missing switch of image display at different down-weighting of the lower energy monoenergetic keV settings. This X-ray photons increases the iodine is especially helpful in cases of sub- contrast-to-noise ratio (CNR) to optimal contrast attenuation – an optimal extent, improving the 3d virtual monoenergetic images can image quality at low-energy display be displayed at lower keV settings for routine diagnosis, as well as (low-energy) to improve contrast enhancement. To illustrate, images 3 Axial images (Figs. 3a & 3b) and that were traditionally displayed coronal MPR images (Figs. 3c & 3d) at 70 keV (equivalent to a standard show lung nodules (arrows) in the 120 kV acquisition), are now right upper and lower lobes. A small routinely displayed at 60 keV, as area of consolidation (dotted arrow) the standard energy level for images is also seen in the right lower lobe. Both central and peripheral lymphan- acquired during the venous phase, gitic carcinomatosis are visualized. Photon-counting CT case reports 11 Case report · Oncology 4 A coronal and an axial view show a 4a 4b bone metastasis in the sternum (Figs, 4a & 4b, arrows). A rib cage unfolding image (Fig. 4c) shows a metastatic lesion in the 7th left-sided rib (dotted arrow). prompting a potential reduction of the radiation dose and the amount of contrast agent needed. 4c As shown in this case, the availability of spectral CT data provided by photon-counting CT plays an important role in clinical routine. The easy switching between energy levels, for image display, enables the physicians to make a comprehensive evaluation of treatment response and to rule out incidental PE, using just a single acquisition during the 5a Examination Protocol venous phase. Scanner NAEOTOM Alpha References Scan area Chest/Abdomen [1] Larici AR, Franchi P, del Ciello A et al. Scan mode QuantumPlus Role of delayed phase contrast-enhanced CT in the intra-thoracic staging of non- Scan length 487 mm small-cell lung cancer (NSCLC): What Scan direction Cranio-caudal does it add ? Eur J Radiol 2021; 144: 109983. Scan time 1.4 s 5b [2] Croft M, Lim WY, Lavender N, Gormly K. Tube voltage 120 kV Optimising CT-chest protocols and the Effective mAs 68 mAs added value of venous-phase contrast timing: observational case-control. Dose modulation CARE Dose4D J Med Imaging Rad Oncol 2022; CTDIvol 5.3 mGy 66: 768-775. DLP 282 mGy*cm [3] Weiss J et al. Noise-optimized mono- energetic post-processing improves Rotation time 0.25 s visualization of incidental pulmonary embolism in cancer patients undergoing Pitch 1.5 5c single-pass dual-energy computed Slice collimation 144 x 0.4 mm tomography. Radiol med (2017) Slice width 1.0 mm 122:280–287. Reconstruction 1.0 mm [4] Thomas Flohr, et al. Photon-counting increment CT review. Physica Medica 79 (2020) 126–136. Reconstruction Br36/BI60 kernel The statements by customers of Siemens Spectral Monoenergetic Plus; Healthineers described herein are based on reconstruction Lung PBV results that were achieved in the customer’s unique setting. Because there is no “typical” 5 Axial images show a thickening hospital and many variables exist (e.g., hospital of bilateral adrenal glands (Fig. 5a, arrows) and two small hypodense Contrast 400 mg/mL size, case mix, level of IT and/or automation adoption) there can be no guarantee that lesions in the liver (Figs. 5b & 5c, Volume 60 mL + 40 mL other customers will achieve the same results. dotted arrows), suspicious of saline metastases. The products/features (mentioned herein) are Flow rate 3 mL/s not commercially available in all countries. Their future availability cannot be guaranteed. * 510k pending. Start delay 70 s 12 Photon-counting CT case reports Oncology · Case report Pancreatic cystic neoplasm – malignant or benign? Bettina K. Budai1, Márton Benke2, Ákos Szücs2, Pál N. Kaposi1, Attila Szijártó2, Pál Maurovich-Horvat1, Ibolyka Dudás 1 1 Department of Radiology, Medical Imaging Centre, Semmelweis University, Budapest, Hungary 2 Department of Surgery, Transplantation and Gastroenterology, Semmelweis University, Budapest, Hungary History Diagnosis delayed diagnosis when a precursor A 76-year-old female patient, had had Virtual-monoenergetic images lesion has already progressed into abdominal CT 6 years ago with the displayed at 65 keV revealed a invasive cancer. [1–2] Due to the finding of an incidental pancreatic lobulated, hypodense lesion located increased availability and improved cystic lesion. The lesion had recently between the pancreatic head and image quality, the probability of shown a slight increase in size and body, measuring 19 × 21 × 17 mm. detecting PCNs has increased. [3-5] therefore the patient was referred Multiple microcystic internal struc- However, in some cases, differential to our hospital for an endoscopic tures, with a maximum diameter diagnosis of PCNs can still be ultrasound (EUS) examination. of less than 4.5 mm each, as well challenging. EUS demonstrated a multi-lobulated, as enhancement of the internal septa This case is performed on a septated cystic lesion, with a in the portal-venous contrast phase, NAEOTOM Alpha®, a newly devel- maximum diameter of 28 mm, were visualized. The pancreatic oped Dual Source CT scanner with located between the head and the duct was not dilatated and showed photon-counting detectors (Quanta- body of the pancreas. The pancreatic no signs of lesion invasion. These CT Max®), providing energy-resolved CT duct showed neither dilatation, findings suggested a diagnosis of data with inherent spectral informa- nor visible communication with a typical SCN without any worrisome tion at improved spatial resolution the lesion. Analysis of the cyst features. Subsequently, the multi- and tissue contrasts, without elec- fluid revealed an elevated CEA disciplinary team agreed with the tronic noise. [6] The spectral data is (1847.0 ng/mL), low glucose content patient on close follow-up examina- available in all routine scans, allowing (0.9 mmol/L) and high amylase level tions without the immediate need for an easy switch of image display at (1240 U/L). These results are more for surgical intervention. different monoenergetic keV settings characteristic of an intraductal for an optimal image visualization. papillary mucinous neoplasm (IPMN), Comments The images acquired during the por- which – depending on its subtype tal and venous phases, which were and location – transformation Pancreatic cystic neoplasm (PCN) traditionally displayed at 70 keV presents a precursor lesion of is a collective term for pancreatic (equivalent to a standard 120 kV invasive pancreatic carcinoma. cystic tumors which have markedly acquisition), now are routinely dis- However, in rare cases, a serous different biological behavior. Main- played at 65 keV, set as the standard cystic neoplasm (SCN), which is duct-IPMN, for example, is considered energy level for an optimal visualiza- considered as a benign entity, can a precursor lesion with a high risk of tion of the contrast-enhanced soft also show high CEA and amylase malignancy, while a SCN is classified tissue structures because of the in- levels. The cytological analysis was as a benign entity with an extremely creased iodine contrast compared inconclusive, raising the possibility low risk of turning into invasive to 70 keV. The combination of the of a pseudocyst, while malignancy cancer. In the management of absence of electronic noise and the could not be confirmed. Further patients diagnosed with PCNs, high- missing down-weighting of the lower assessment was requested by end imaging with CT, MRI or EUS energy X-ray photons further increases contrast-enhanced CT and this plays a central role. The goal is to the iodine contrast-to-noise ratio examination was conducted on provide accurate diagnosis in order (CNR), improving the image quality the newly installed photon-counting to avoid unnecessary surgery on at low-energy display for routine CT (PCCT) in our hospital. the one hand side, and to prevent diagnosis. Images are routinely Photon-counting CT case reports 13 Case report · Oncology 1a 1b 1 A coronal MPR image acquired on PCCT (Fig. 1a, 3 mm) shows a lobulated, hypodense lesion at the junction of the pancreatic head and body. Multiple microcystic internal structures (arrows) are clearly visualized. In a similar coronal view acquired 6 months earlier on a conventional CT (Fig. 1b, 3 mm), these microcysts are not depicted. 2a 2b 2 Two enlarged views show the microcysts (Fig. 2a, arrows), and a clear separation between the lesion and the pancreatic duct, characterizing a typical SCN. 3a 3b 3 Cinematic VRT images show the lesion (Fig. 3a, arrow) and the adjacent structures. An enlarged view (Fig. 3b) shows the microcysts in the lesion and the separation between the lesion and the pancreatic duct in three dimensions. 14 Photon-counting CT case reports Oncology · Case report acquired at 0.4 mm slices and recon- structed with a sharper kernel Examination Protocol of Br44, providing increased spatial resolution compared to conventional Scanner NAEOTOM Alpha standard abdominal CT. As shown in Scan area Abdomen this case, owing to the improved CNR and the spatial resolution, Scan mode QuantumPlus the detailed visualization of the (native/arterial/portal/venous) microcystic internal structures, the Scan length 414 / 209 / 122 / 415 mm enhancing internal septa in the por- tal phase and the clear separation Scan direction Cranio-caudal between the tumor and the pancre- Scan time 4.4 / 2.2 / 1.2 / 4.4 s atic duct, help the radiologists make a confident differential diagnosis on Tube voltage 120 kV PCNs, preventing unnecessary surgi- cal interventions and potential Effective mAs 145 / 157 / 115 / 114 mAs complications for the patient. Dose modulation CARE Dose4D CTDIvol 11.5 / 12.3 / 9 / 8.9 mGy References DLP 516 / 199 / 141 / 404 mGy*cm [1] The European Study Group on Cystic Rotation time 0.5 s Tumours of the Pancreas. European evidence-based guidelines on pancreatic Pitch 0.8 cystic neoplasms. Gut. 2018; 67(5):789-804. Slice collimation 144 × 0.4 mm [2] Tanaka M, Fernández-Del Castillo C, Slice width Kamisawa T, Jang JY, Levy P, Ohtsuka T, 0.4, 1.0, 2.0, 3.0 mm et al. Revisions of international consensus Reconstruction increment 0.4, 0.5, 1.5, 3.0 mm Fukuoka guidelines for the management of IPMN of the pancreas. Pancreatology: Reconstruction kernel Br44, Qr40 official journal of the International Association of Pancreatology (IAP) [et al]. Spectral reconstruction Monoenergetic Plus 2017; 17(5):738-753. [3] Gaujoux S, Brennan MF, Gonen M, D'Angelica MI, DeMatteo R, Fong Y, et al. Contrast 350 mg/mL Cystic lesions of the pancreas: changes in the presentation and management Volume 77 mL + 40 mL saline of 1,424 patients at a single institution Flow rate 3.1 mL/s + 3.2 mL/s over a 15-year time period. Journal of the American College of Surgeons. 2011; Start delay Arterial phase: 23 s 212(4):590-600; discussion 600-593. Portal phase: 45 s [4] Laffan TA, Horton KM, Klein AP, Venous phase: 75 s Berlanstein B, Siegelman SS, Kawamoto S, et al. Prevalence of unsuspected pancreatic cysts on MDCT. AJR American journal of roentgenology. 2008; 191(3):802-807. [5] Moris M, Bridges MD, Pooley RA, Raimondo M, Woodward TA, Stauffer JA, et al. Association Between Advances in High-Resolution Cross-Section Imaging Technologies and Increase in Prevalence of Pancreatic Cysts From 2005 to 2014. Clinical gastroenterology and hepatology: the official clinical practice journal of the The statements by customers of Siemens Healthineers described herein are based on results that were achieved in the customer’s unique setting. American Gastroenterological Association. Because there is no “typical” hospital and many variables exist (e.g., hospital 2016; 14(4):585-593.e583. size, case mix, level of IT and/or automation adoption) there can be no [6] Thomas Flohr, et al. Photon-counting guarantee that other customers will achieve the same results. CT review. Physica Medica 79 (2020) The products/features (mentioned herein) are not commercially available 126–136. in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 15 Case report · Oncology Inside an incidental solid renal mass Jan Baxa, MD, Ph.D. Department of Imaging Methods, University Hospital Pilsen and Medical Faculty of Charles University, Pilsen, Czech Republic History CT findings were compatible with a improved iodine CNR, due to the An 89-year-old male patient, renal neoplasm. However, due to the missing down-weighting of the lower complaining of unspecific abdominal patient’s age and physical condition, energy X-ray photons, the absence pain and hematuria, came to the no immediate surgery nor further of the electronic noise, and the hospital for a checkup. Physical examinations were performed. inherent spectral information, the examination and laboratory tests Medication for the prostatic hyper- small, enhanced lesion inside the suggested a prostatic hyperplasia as plasia and surveillance for the renal mass, invisible and likely missed in the cause of hematuria. For further mass were recommended. standard CT images, is clearly depicted assessment and to rule out any other in the Monoenergetic Plus images potential cause of hematuria, an Comments displayed at 40 keV, as well as in the abdominal contrast CT scan on a dual iodine maps fused with VNC images. source photon-counting CT (PCCT), Incidental findings in the kidneys are common and most of these are renal The VNC images are routinely derived NAEOTOM Alpha®, was performed. masses. [1] Solid masses are defined from the contrast scan, avoiding the as those that contain little or no fluid necessity of having to perform a non- Diagnosis attenuating (<20 HU) components contrast scan or to call the patient and usually predominantly consist back. Furthermore, the improved Standard CT images (Monoenergetic of enhancing tissue. [2] When hyper- spatial resolution of PCCT facilitates Plus images displayed at 70 keV, densities are identified in small renal the characterization of the small corresponding to conventional CT images acquired at 120 kV) showed masses, it is of utmost importance enhancing lesion with a diameter to differentiate between a cyst, of only few millimeters and the tiny an incidental renal mass in the right with only hyperdense content branch of the renal artery that kidney, homogeneously enhanced (75 HU), well marginated with an (hemorrhage or proteins), and a supplies it. In the routine workflow, tumor with contrast enhancement. viewing of different image types, imperceptible wall, measuring In a clinical routine, using conventional such as standard CT image, Mono- 2.0 x 1.6 cm2 in size. The enhance- ment pattern in the arterial, venous, CT scanners, additional non-contrast energetic Plus images displayed at different keV levels, VNC image, and delayed phases showed no CT or MRI must be performed to confirm or exclude post-contrast iodine image and iodine/VNC fused remarkable differences. In the virtual unenhanced (VNC) images, the mass enhancement. If an incidental renal image, can be toggled interactively, was slightly hyperdense (49 HU), mass is visualized in contrast scans, using Interactive Spectral Imaging such as this case, the patient needs (ISI) technique, which greatly facili- with no calcifications present. Monoenergetic Plus images displayed to be re-scheduled for a non-contrast tates image reading and improves the efficiency of routine diagnosis. at 40 keV revealed a significantly scan. For a proper diagnosis and enhanced small lesion (112 HU), subsequent patient management, In this case, a conservative approach dorsally in the mass, invisible in a small renal mass needs to be completely characterized, which can for the subsequent patient’s manage- the standard CT images, measuring 0.4 x 0.5 cm2 in size. In the iodine be challenging and requires optimal ment is chosen, considering limited life expectancy and possible co- maps fused with VNC images, the iodine contrast-to-noise ratio (CNR). morbidities, therefore the nature of iodine density was measured to This case is performed on NAEOTOM the renal mass with the small lesion be 0.92 mg/mL for the mass and Alpha, a newly developed dual inside is not pathologically con- 1.8 mg/mL for the small lesion. In the source CT scanner with photon- firmed. However, this case demon- 3D visualization, using thin maximum counting detectors (QuantaMax®), strates the great potential of PCCT intensity projection (MIP) and cinematic providing energy-resolved CT data in depicting such a small, enhanced volume rendering techniques (cVRT), with inherent spectral information lesion as well as a tiny supplying a tiny branch of the renal artery and improved tissue contrasts in artery, helping the physicians to supplying the mass was depicted. routine scans. [3] Owing to the make a confident diagnosis. 16 Photon-counting CT case reports Oncology · Case report 1a 1b 1c 1d 1 A standard axial image (Fig. 1a) shows a homogeneously contrast enhanced mass in the right kidney. A Monoenergetic Plus image displayed at 40 keV (Fig. 1b) and an iodine map fused with VNC image (Fig. 1c) reveal a significantly enhanced small lesion dorsally in the mass, which is invisible in the standard image. In a VNC image (Fig. 1d), the mass is slightly hyperdense with no calcifications present. 2a 2b FLIT FLH 2 A cVRT image (Fig. 2a) and a thin MIP image (Fig. 2b) show a tiny branch of the renal artery supplying the mass (arrows). Photon-counting CT case reports 17 Case report · Oncology Examination Protocol Scanner NAEOTOM Alpha Scan area Abdomen Scan mode QuantumPlus (Arterial/Venous/delayed) Scan length 420 / 334 / 373 mm Scan direction Cr-ca / ca-cr/ cr-ca Scan time 4.5 / 3.6 / 3.6 s Tube voltage 120 / 120 / 90 kV Effective mAs 108 / 108 / 112 mAs Dose modulation CARE Dose4D CTDIvol 8.4 / 8.5 / 4.0 mGy DLP 386 / 367 / 165 mGy*cm Rotation time 0.5 s Pitch 0.8 / 0.8 / 0.9 Slice collimation 144 x 0.4 mm Slice width 0.6 / 0.4 / 0.6 mm Reconstruction increment 0.4 / 0.2 / 0.4 mm Reconstruction kernel Br40 / Qr40 / Br40, QIR 3 Spectral reconstruction Monoenergetic Plus, iodine map, VNC Contrast 350 mg/mL References Volume 100 mL + 40 mL saline [1] Aslam Sohaib. Incidental solid cystic Flow rate renal lesion. Cancer Imaging (2012) 12(2), 4 mL/s 385-386. doi: 10.1102/1470- Start delay Arterial phase: Bolus tracking 7330.2012.9034. triggered at 100HU in the distal [2] Mahesh Kumar Mittal, Binit Sureka. Solid thoracic aorta + 5 s. renal masses in adults. Indian J Radiol Venous phase: 35 s after finishing Imaging. 2016 Oct-Dec; 26(4): 429–442. doi: 10.4103/0971-3026.195773. of the arterial phase. Delayed phase: 10 minutes after [3] Thomas Flohr, et al. Photon-counting the finishing of the venous phase. CT review. Physica Medica 79 (2020) 126–136. The statements by customers of Siemens Healthineers described herein are based on results that were achieved in the customer’s unique setting. Because there is no “typical” hospital and many variables exist (e.g., hospital size, case mix, level of IT and/or automation adoption) there can be no guarantee that other customers will achieve the same results. The products/features (mentioned herein) are not commercially available in all countries. Their future availability cannot be guaranteed. 18 Photon-counting CT case reports Oncology · Case report Two small non-invasive papillary urothelial carcinomas in the left renal pelvis and ureter Prof. Jan Baxa, MD, Ph.D. Department of Imaging Methods, University Hospital Pilsen and Medical Faculty of Charles University, Pilsen, Czech Republic History (staging pTa, N0, M0) was histologi- smaller sub-pixels which are read A 76-year-old male patient, suffering cally confirmed through biopsy and out separately to increase the spatial from repeated episodes of renal ureteroscopy. The patient underwent resolution. This approach also colic associated with hematuria, laser ablation of the tumors through improves the geometrical dose effi- had undergone two non-contrast cystoscopy, without adjuvant therapy ciency of the detector. In this case, CT scans to detect renal calculi; how- recommended. the entire range of the abdomen and ever, both were negative. Urine pelvis is acquired with 0.4 mm slices cytology analysis, to detect urothelial Comments at a radiation dose of only 7.2 mGy. cancer, also resulted negatively. The CNR is optimized due to a combi- A contrast enhanced CT scan was Urothelial carcinoma, also called nation of missing down-weighting of requested and performed, in both transitional cell carcinoma, originates the lower energy X-ray photons, the the venous and late excretory phase, in the urothelial cells. It is the most absence of the electronic noise and with a photon-counting CT (PCCT), common cancer of the renal pelvis or the inherent spectral information. NAEOTOM Alpha®, for further ureter, making up about 90% of all CT data acquired in a contrast scan upper urinary tract tumors. If the can then be used for further spectral assessment. cancer is confined to the urothelium, reconstructions, such as virtual it is non-invasive and curable in more non-contrast (VNC) images, virtual Diagnosis than 90% of the patients. If it has monoenergetic images (Mono- CT images acquired in the venous infiltrated into deeper layers of the energetic Plus) displayed at different phase revealed two small lesions, urothelial wall, the likelihood of cure keV levels, iodine maps and iodine/ measuring 7 mm × 5 mm in size, is 10–15%. In case it has infiltrated VNC fused images. In fact, reading in the left ureteropelvic junction and, through the urothelial wall or distant these different image types in daily 8 mm × 7 mm, in the left middle metastases have occurred, it is usually practice is quite straightforward, ureter. Both lesions were contrast incurable with available treatment. as they can be interactively toggled, enhanced. Using spectral recon- The depth of infiltration is a major using Interactive Spectral Imaging structions, the enhancement was prognostic factor at the time of (ISI) technique available with image clearly improved in the iodine maps diagnosis, therefore, a proper early viewing. As one of the key benefits and in the Monoenergetic Plus diagnosis is relevant. In CT imaging, of PCCT, spectral information is images displayed at 40 keV, compared the identification and characteriza- available in any scan. It is highly to standard CT images (displayed tion of small lesions at an early stage recommended to utilize this at 70 keV, corresponding to images require both high spatial resolution information in image reading for acquired at 120 kV). In the virtual and optimal tissue contrasts, and routine diagnosis. non-contrast (VNC) images, both ideally, not at the cost of radiation lesions appeared isodense. The left dose efficiency. This is technically As shown in this case, the renal pelvis was dilated. No abnor- very challenging. identification and characterization of the two small enhancing lesions, malities, neither in the right renal PCCT provides energy-resolved CT only a few millimeters in size, pelvis and ureter nor in the bladder, data at increased spatial resolution benefit from the advantages were seen. without electronic noise and with provided by PCCT, helping the improved tissue contrasts. [1] An physicians make a confident Subsequently, a low grade non- electric field, instead of physical diagnosis. invasive papillary urothelial carcinoma separation, is applied to define Photon-counting CT case reports 19 Case report · Oncology 1a 2a 1 2 Two small lesions are shown in the left ureteropelvic junction (Fig. 1, arrows) and in the middle ureter (Fig. 2, dotted arrows). The lesions appear isodense in the VNC images (Fig. a), slightly enhanced in standard CT images (Fig. b) and clearly enhanced in the Mono- energetic Plus images displayed at 40 keV (Fig. c) as well as in the iodine/VNC fused images (Fig. d). The left 1b 2b renal pelvis is dilated (Fig. 1). 1c 2c 1d 2d 20 Photon-counting CT case reports Oncology · Case report 3a 3b 3 Cinematic VRT images show three dimensional views of the two small lesions in the left ureteropelvic junction (arrows) and in the middle ureter (dotted arrows). --- Examination Protocol Scanner NAEOTOM Alpha Scan area Abdomen/Pelvis Slice width 0.4 mm Scan mode QuantumPlus Reconstruction increment 0.2 mm Scan length 489 mm Reconstruction kernel Br40 QIR 3 Scan direction Cranio-caudal keV level 60 keV Scan time 5.3 s Spectral reconstruction VNC, Monoenergetic Plus, iodine map Tube voltage 120 kV Effective mAs 91 mAs Contrast 370 mg/mL IQ level 135 Volume 1st bolus (70 mL + 40 mL saline) Dose modulation CARE Dose4D 20 s pause – – CTDIvol 7.2 mGy 2nd bolus (30 mL + 20 mL saline) DLP 382 mGy*cm Flow rate 4 mL/s Rotation time 0.5 s Start delay Bolus tracking triggered in Pitch 0.8 the 2nd bolus with 100 HU in the distal descending aorta Slice collimation 144 × 0.4 mm + 5 s References The statements by customers of Siemens Healthineers described herein are based on results that were [1] Thomas Flohr, et al. Photon-counting achieved in the customer’s unique setting. Because there is no “typical” hospital and many variables exist CT review. Physica Medica 79 (2020) (e.g., hospital size, case mix, level of IT and/or automation adoption) there can be no guarantee that other customers will achieve the same results. 126–136. The products/features (mentioned herein) are not commercially available in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 21 Case report · Oncology Pancreatic insulinoma in a patient with a history of hypoglycemia Antonella Del Gaudio, MD; Daniele Marin, MD Department of Radiology, Duke University, Durham, NC, USA History Comments A 63-year-old female patient (BMI Insulinoma is a type of functional References 19.57 kg/m²), with a history of hypo- pancreatic neuroendocrine tumor [1] Marc Díez, Alexandre Teulé, Ramon thyroidism, fatigue, weakness, loss (pNET) originating from the endo- Salazar. Gastroenteropancreatic of appetite and hypoglycemia, was crine cells of the pancreas. It is neuroendocrine tumors: diagnosis and treatment. Ann Gastroenterol. referred to the Department of Radiol- often confined to the pancreatic 2013; 26(1): 29–36. ogy for evaluation. A calcium stimu- gland and characterized by hyper- lation challenge test showed diffuse secretion of insulin causing hypo- [2] Thomas Flohr, et al. Photon-counting insulin secretion throughout the glycemia. Surgery is the only poten- CT review. Physica Medica 79 (2020) pancreas. A pancreatic insulinoma tially curative therapeutic strategy 126–136. was suspected. However, a previous in localized disease, and generally, CT examination performed with small pancreatic insulinomas an Energy Integrating Detector CT have a very good prognosis. [1] (EID-CT) did not reveal any pancreatic The challenge, though, lies in the lesion. A contrast CT scan with a identification of the primary tumor dual source photon-counting detec- due to its small size. tor CT (PCD-CT), NAEOTOM Alpha®, was performed for further evaluation. PCD-CT provides energy-resolved CT data with increased spatial resolu- tion and inherent spectral informa- Diagnosis tion. [2] Tissue contrast is optimized by a combination of missing down- Virtual monoenergetic images weighting of the lower energy X-ray (VMIs), displayed at 50 KeV, revealed photons and absence of electronic a hypervascular nodular lesion in noise. In this case, an ultra-high reso- the pancreatic body in the arterial lution (UHR) mode was performed, phase, measuring 1 cm in size. The using a fine collimation of 120 x lesion was also seen in the iodine 0.2 mm, in the arterial phase. This maps and the VNC/iodine fused mode uses smaller sub-pixels, de- images. In the virtual non-contrast fined by a strong electric field with- (VNC) images, it appeared isodense, out further mechanical separation, and in the standard image recon- which are read out separately to structions, it was inevident. Subse- increase the spatial resolution. VMIs quently, the lesion was confirmed are then reconstructed at 0.4 mm The statements by customers of by a Dotatate PET/CT scan as well and displayed at 50 keV to enhance Siemens Healthineers described herein are based on results that were achieved in the customer’s as an Endoscopy Ultrasound (EUS) the contrast. The small insulinoma, unique setting. Because there is no “typical” examination. The patient underwent initially missed by EID-CT, is clearly hospital and many variables exist (e.g., hospital a distal pancreatectomy with visualized owing to the combination size, case mix, level of IT and/or automation adoption) there can be no guarantee that other splenectomy. The pathology result of increased spatial resolution and customers will achieve the same results. confirmed the diagnosis of a G1 tissue contrast. This facilitates an well-differentiated neuroendocrine appropriate surgical planning and The products/features (mentioned herein) are not commercially available in all countries. tumor with insulin hyperproduction. thereby an optimal patient outcome. Their future availability cannot be guaranteed. 22 Photon-counting CT case reports Oncology · Case report 1a 2a Examination Protocol Scanner NAEOTOM Alpha Scan area Abdomen / Abdomen-Pelvis Scan mode UHR / Quantum- plus (Arterial / venous phases) 1b 2b Scan length 249.6 / 423.2 mm Scan direction Cranio-caudal Scan time 5.2 / 4.5 s Tube voltage 140 kV Effective mAs 156 / 67 mAs IQ level 280 / 227 Dose modulation CARE Dose4D 1c 2c CTDIvol 18.2 / 7.7 mGy DLP 487 / 352 mGy*cm Rotation time 0.5 s Pitch 1.0 / 0.8 Slice collimation 120 × 0.2 / 144 × 0.4 mm Slice width 0.2, 0.4 / 0.4 mm 1 An axial VMI, acquired in the arterial 2 An iodine map (Fig. 2b) and a VNC/ Reconstruction 0.2 / 0.4 mm phase and displayed at 50 keV, show iodine fused image (Fig. 2c) show a a small hypervascular nodular lesion contrast enhanced lesion (arrows) in increment in the pancreatic body (Fig. 1c, arrow). the pancreatic body. The lesion appears isodense in the VNC image (Fig. 2a) Reconstruction Br48, Qr40 / Qr40 The lesion is neither shown in a previous EID-CT image (Fig. 1a) nor kernel evident in a standard image recon- struction (Fig. 1b). keV level 50 keV Spectral Monoenergetic 3a 3b reconstruction Plus Contrast 300 mg/mL Volume 150 mL Flow rate 4 mL/s Start delay 1, Arterial phase: bolus tracking triggered at 3 A Dotatate PET/CT image shows a small 150 HU in the lesion spotted in the pancreatic body descending aorta (Fig. 3a, arrow). The lesion is clearly + 17 s seen in a cinematic VRT image created with UHR images as well (Fig. 3b, 2, Venous phase: arrow). 45 s Photon-counting CT case reports 23 Case report · Oncology A well-differentiated, invasive ductal adenocarcinoma in the pancreatic body Prof. Jan Baxa, MD, PhD Department of imaging methods, University Hospital Pilsen and Medical Faculty of Charles University, Pilsen, Czech Republic History A 69-year-old male patient, com- was no evidence of vascular encase- a complete surgical resection. [2] plaining of abdominal pain and ment. The celiac artery (CA), the Therefore, a careful pre-operative discomfort slowly progressing over superior mesenteric artery (SMA) assessment is crucial for an upfront the past three months, came to the and the portal vein did not show patient stratification. CT is consid- hospital for a check-up. The patient CT-signs of invasion. No metastases ered the modality of choice for had a new onset of diabetes mellitus. of the liver or local lymph nodes tumor staging. Pre-operative evalua- Ultrasound examination revealed were seen, neither on CT, nor on liver tions on vascular variations and a partially solid and partially cystic MRI. A subsequent endoscopic ultra- stenoses are also important for the mass in the pancreatic body, with sound examination revealed no surgeons, allowing for a proper suspicious invasion into the gastric tumor invasion into the gastric wall. surgical planning, avoiding intra- wall. A contrast-enhanced CT exami- After completed staging, imaging operative vascular injuries and post- nation was requested and performed findings suggested a resectable operative complications. with a dual source, photon-counting pancreatic ductal adenocarcinoma detector (PCD) CT, NAEOTOM Alpha®, (PDAC), stage IIa, T3 N0 M0. PCD-CT provides energy-resolved for further local assessment of the CT data with increased spatial pancreatic mass and disease staging. The patient underwent surgical resolution and inherent spectral resection of the tumor. CT findings information. [3] VMI can be recon- Diagnosis were intra-operatively confirmed. structed and displayed at different A post-operative pathological evalua- keV levels in routine scans. The CT images showed a well-defined, tion confirmed a complete tumor tissue contrast is increased in VMI exophytic mass in the pancreatic resection with free resection margins displayed at 40 keV compared to VMI body, causing obstruction with (R0). A histological analysis revealed displayed at 70 keV (equivalent to a upstream dilatation of the main pan- a well-differentiated invasive ductal standard image acquired at 120 kV) creatic duct. The mass, measuring adenocarcinoma. The patient contin- and is further optimized by a combi- 4.5 cm x 4.6 cm in size, was hypo- ued with neoadjuvant chemotherapy nation of missing down-weighting attenuating in the virtual non-con- and has been, to-date, free from of the lower energy X-ray photons trast (VNC) images, and hypovascular recurrence. and absence of electronic noise. As in the arterial and portal-venous shown in this case, the combination contrast phases. Virtual mono- Comments of increased spatial resolution and energetic images (VMI) displayed tissue contrast is beneficial for the at 40 keV showed an increased con- PDAC is the most common pancreatic visualization of a thin rim of the trast enhancement, resulting in an malignancy, accounting for more tumor and the fatty tissue between improved visualization of a brighter than 85% of pancreatic tumors, the tumor and the gastric wall. This rim of the tumor adjacent to the with poor prognosis and rising inci- helps enhancing physician’s confi- gastric wall and the fatty tissue dence. In early stages, it is usually dence in differentiating desmoplas- between the tumor and the gastric asymptomatic. Approximately 80% tic reaction from tumor invasion, wall. This indicated the likelihood of the cases are diagnosed at an critical for assessment on tumor of a desmoplastic reaction rather advanced stage (T3 or T4). [1] The resectability, and subsequently, than an invasion of the tumor. There only potential curative treatment is patient’s outcome. 24 Photon-counting CT case reports Oncology · Case report 1a 1b 1c 1d 1 Axial images (Fig. 1a & 1b) and oblique MPR images (Fig. 1c & 1d) show a well-defined, hypovascular mass in the pancreatic body. Compared to VMI images displayed at 70 keV (Fig. 1a & 1c), the VMI images displayed at 40 keV (Fig. 1b & 1d) show an increased contrast enhancement, resulting in an improved visualization of a brighter rim of the tumor (Fig. 1a & 1b, dotted arrows) adjacent to the gastric wall and the fatty tissue between the tumor and the gastric wall (arrows), indicating the likelihood of a desmoplastic reaction, rather than an invasion of the tumor. References [1] K. Schawkat, et al. Pancreatic Ductal Adenocarcinoma and Its Variants: Pearls and Perils. RadioGraphics 2020; 40:1219–1239. https://doi.org/10.1148/ The statements by customers of rg.2020190184. Siemens Healthineers described herein are based on results that were achieved in the customer’s [2] Khaled Y. Elbanna, Hyun-Jung Jang and Tae Kyoung unique setting. Because there is no “typical” Kim. Imaging diagnosis and staging of pancreatic hospital and many variables exist (e.g., hospital ductal adenocarcinoma: a comprehensive review. size, case mix, level of IT and/or automation Insights into Imaging (2020) 11:58. adoption) there can be no guarantee that other customers will achieve the same results. https://doi.org/10.1186/s13244-020-00861-y. The products/features (mentioned herein) are [3] Thomas Flohr, et al. Photon-counting CT review. not commercially available in all countries. Physica Medica 79 (2020) 126–136. Their future availability cannot be guaranteed. Photon-counting CT case reports 25 Case report · Oncology 2a 2b 2c 2d 2 Cinematic VRT images show a three-dimensional view of the tumor (Fig. 2a–2c) and the arteries (Fig. 2d). The tumor is located in the pancreatic body (arrows), showing no evidence of gastric wall invasion. Normal branches of the CA and the SMA are shown, without variation or stenoses. Examination Protocol Scanner NAEOTOM Alpha Scan area Abdomen/Pelvis Reconstruction increment 0.2 mm Scan mode Quantumplus Reconstruction kernel Bv40, QIR 3 (arterial & portal-venous phases) keV level 70, 60, 40 keV Scan length 541 mm Spectral reconstruction VNC, VMI Scan direction Cranio-caudal Scan time 5.8 s Tube voltage 120 kV Contrast 370 mg/mL Effective mAs 152 mAs Volume 1st bolus (70 mL + 40 mL saline) IQ level 125 20 s pause – – Dose modulation CARE Dose4D 2nd bolus CTDIvol 12 mGy (30 mL + 20 mL saline) Flow rate 4 mL/s DLP 702 mGy*cm Start delay Arterial phase was triggered Rotation time 0.5 s immediately after 100 HU is Pitch 0.8 reached in descending aorta Slice collimation in the 2nd bolus; the venous 144 × 0.4 mm phase was started 25 s after Slice width 0.4 mm the end of the arterial phase. 26 Photon-counting CT case reports Pulmonology · Case report Follow-up of an acute pulmonary embolism in an obese patient with an unknown patent foramen ovale Prof. Martine Rémy-Jardin, MD1, Ph.D.; Prof. Jacques Rémy, MD2 1 Department of Thoracic Imaging, University Centre of Lille, France 2 Department of Radiology, Hospital Center of Valenciennes, France History A 38-year-old female obese patient However, in the middle third of the a systemic embolization, such as (165 cm height, 109 kg weight, acquisition, the opacification in the the cryptogenic stroke which this BMI 40) suffered from an acute pulmonary arteries (PA) was insuffi- patient had suffered. In a CT chest pulmonary embolism (PE) eighteen cient and slightly heterogeneous, examination, a reversal blood flow months ago. Her medical history raising concerns about persistent (right-to-left shunt) can also occur included severe thrombotic context clots in the left interlobar PA and when the patient takes a deep with several episodes of extensive bilateral proximal lower lobe PAs. breath and holds it while executing lower extremity phlebitis, venous When switching image display from a Valsalva maneuver. As a conse- thrombosis and cryptogenic stroke. 70 keV to 40 keV, the attenuation quence, the contrast is directed from Despite adequate anticoagulant within the pulmonary trunk (457 the right atrium to the left atrium, treatment of the acute PE episode, HU), as well as in the segmental although a “jet sign” may not be her dyspnea persisted. The patient PAs, was restored to a diagnostic present, leading to a poor opacifica- was referred for a CT pulmonary level and the absence of residual tion of pulmonary arteries and a angiography (CTPA) to clarify clots could be confirmed. good opacification of the aorta, a potential evolution towards such as in this case. This may chronic pulmonary embolism. Based on CT findings, the treating potentially limit the diagnosis of physician considered that the PE requiring repeated scans with re- Diagnosis patient was resistant to the anti- administration of contrast material. coagulant she had been receiving CTPA images displayed at 70 keV since previous thrombotic events, This case is performed on a (equivalent to a standard 120 kV and subsequently, switched her NAEOTOM Alpha®, a newly devel- acquisition) showed a poor opacifi- treatment plan to a different oped Dual Source CT scanner with cation of the pulmonary arteries anticoagulant. photon-counting detectors (Quanta- (158 HU within the pulmonary trunk) Max®), providing energy-resolved CT and a good opacification in the data without electronic noise. [3] aorta, indicating the potential Comments One of the key benefits of photon- existence of a patent foramen ovale counting CT (PCCT) is the availability PFO is a communication between (PFO) with a right-to-left shunt. the right and left atria which fails of spectral CT data in any scan, al- The upper and lower thirds of the to close postpartum. It has a high lowing for an easy switch of the im- acquisition were not affected despite incidence in the general population, age display at different monoener- this shunt – the segmental artery existing approximately in one-third getic keV settings. By displaying the of the right upper lobe (RA1), of the adults. [1] Most people with images at a lower keV setting, an previously obstructed and dilated a PFO remain asymptomatic and acquisition which missed the by the acute thrombus, presented do not require any treatment. [2] contrast bolus due to the opening severe stenosis, confirming focal However, the presence of a PFO of a PFO can be salvaged. It is also worth noting that the overall image chronic PE. A clot in the lateral may facilitate a paradoxical thrombo- segmental artery of the right lower quality in this investigation achieved embolus to transit from the venous lobe (RA9) was persistently seen. to the systemic circulation and cause an optimal level despite the patient morphotype – obesity is usually Photon-counting CT case reports 27 Case report · Pulmonology 1a 1b 1c 1 The segmental artery of the right upper lobe (RA1), previously obstructed and dilated at the time of acute PE (Fig. 1a, arrow), is poorly perfused in images displayed at 70 keV and shows severe retraction (Figs. 1b and 1c, arrows), confirming focal chronic PE. 2a 2b 2 A clot previously shown in the lateral segmental artery of the right lower lobe (RA9) (Fig. 2a, arrow) is persistently seen in an image displayed at 70 keV (Fig. 2b, arrow). 3a 3b 3 The poor opacification of 158 HU in the pulmonary trunk in the image displayed at 70 keV (Fig. 3a) is restored to a diagnostic level of 457 HU in the image displayed at 40 keV (Fig. 3b). 1031 15B HU21 H associated with image graininess As shown in this case, the availability References due to noise, hampering precise of spectral CT data provided by [1] Joel P Giblett, et al. Patent Foramen Ovale analysis of pulmonary arterial Quantum Technology plays an Closure: State of the Art. Interventional sections, especially in the distal important role in clinical routine. Cardiology Review 2020;15:e15. divisions. The reduction of image In an obese patient with an unknown [2] Ahmed R Gonnah, et al. Patent foramen noise is particularly enhanced by PFO, the use of low-energy images ovale: diagnostic evaluation and the role the absence of electronic noise enables the physicians to restore the of device closure. Clinical Medicine 2022 which is dominant at low X-ray flux diagnostic image quality and perform Vol 22, No 5: 441–8. at the detector, such as in the case a complete analysis of pulmonary of a bariatric CT scan. Additionally, a arteries, without having to repeat [3] Thomas Flohr, et al. Photon-counting CT review. Physica Medica 79 (2020) model based iterative reconstruction the scan and re-administer contrast 126–136. approach – Quantum Iterative material. CT findings allow the Reconstruction (QIR) – is also applied physician to explain the worsening in the image reconstruction process, of the patient’s situation and to contributing to further image noise consider changing the treatment reduction. plan. 28 Photon-counting CT case reports Pulmonology · Case report 4a 4b 4c 4d 4e 4f 4 Previous acute PE (Figs. 4a & 4d) are shown in bilateral interlobar PA (arrows) and bilateral basal trunks (dotted arrows). Images displayed at 70 keV (Figs. 4b and 4e) show slightly heterogenous opacification and raise the concern about persistent clots. This is ruled out in the images displayed at 40 keV (Figs. 4c and 4f). Examination Protocol Scanner NAEOTOM Alpha Contrast 400 mg/mL Scan area Thorax Volume 60 mL + 40 mL saline Scan mode QuantumPlus Flow rate 3 mL/s Scan length 280 mm Start delay Bolus tracking triggered Scan direction Caudo-cranial at 150 HU in the ascending aorta + 3 s Scan time 0.8 s Tube voltage 120 kV Effective mAs 134 mAs Dose modulation CARE Dose4D CTDIvol 10.4 mGy DLP 356 mGy*cm Rotation time 0.25 s Pitch 1.5 Slice collimation 144 x 0.4 mm The statements by customers of Siemens Healthineers described herein are Slice width 1.0 mm based on results that were achieved in the customer’s unique setting. Because there is no “typical” hospital and many variables exist (e.g., hospital size, case Reconstruction increment 1.0 mm mix, level of IT and/or automation adoption) there can be no guarantee that Reconstruction kernel Br36 / BI60 other customers will achieve the same results. Spectral reconstruction Mono + The products/features (mentioned herein) are not commercially available in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 29 Case report · Pulmonology Chronic thromboembolic pulmonary hypertension diagnosed after COVID-19 Prof. Martine Rémy-Jardin, MD1, Ph.D.; Prof. Jacques Rémy, MD2 1 Department of Thoracic Imaging, University Centre of Lille, France 2 Department of Radiology, Hospital Center of Valenciennes, France History on the chest CTA, the patient was oped CT scanner with photon-count- An 83-year-old male patient, with considered as eligible for pulmonary ing detectors, providing energy-re- a previous episode of massive acute thromboendarterectomy (PTE), solved CT data at improved spatial thromboembolic disease within the after medical treatment to decrease resolution, with inherent spectral context of COVID-19, was diagnosed the level of pulmonary vascular information and improved tissue with pre-capillary pulmonary resistance prior to surgery. contrasts, without electronic noise. hypertension (PH). He was referred [3] All of these contribute to benefits for a contrast enhanced chest CT and improvements in chest CT to evaluate the etiology of the PH. Comments imaging. As an example, the iodine The cardiologist in charge suspected PH is a hemodynamic condition contrast-to-noise ratio (CNR) is that the chronic thromboembolic defined by a mean PA pressure (PAP) improved due to the missing down- pulmonary hypertension (CTEPH) greater than 20 mm Hg and is weighting of the lower energy was pre-existent to the hospitaliza- clinically classified into five different X-ray photons and the absence of tion for COVID-19 and was searching groups, sharing similar pathophysio- electronic noise, prompting a for potential fibrotic sequelae of logic mechanisms, hemodynamic potential reduction of the radiation COVID-19 in the lungs. characteristics and therapeutic dose and the amount of contrast management. [1] CTEPH is classified agent needed. Another benefit is the availability of spectral CT data in Diagnosis in group 4 in which pulmonary artery obstructions are responsible for PH. each contrast scan, i.e., the iodine CT angiography (CTA) images maps – also known as LungPBV – showed dilation of the central The incidence of PE in the context can be created with each CTA data- pulmonary arteries (PA), tapering of COVID-19 has been reported but set, resulting in a simultaneous and pruning of the peripheral PA, there is no data on post COVID-19 assessment of the pulmonary significant enlargement of the right CTEPH. [2] An acute PE may lead to vasculature as well as analysis of atrium as well as a moderate en- CTEPH due to an abnormal persistent the parenchymal iodine distribution. largement of the right ventricle, obstruction of the PAs by residual Due to the high scan speed, spectral intravascular webs and filling defects, organized thrombi, combined with data of the entire thorax can be a dilated bronchial artery, along with a variable degree of microscopic obtained in less than 2 s. This has a a pattern of mosaic perfusion in both vasculopathy. CTEPH has a poor major impact on improving routine lungs. In the spectral image data prognosis when left untreated, workflow. In the clinical context assessment of the lung perfused leading to right heart failure as a of PH, previous studies have shown blood volume (LungPBV*), multiple result of progressive right ventricular agreement between LungPBV peripheral wedge-shaped perfusion dysfunction. An early recognition and scintigraphy for the detection defects were evident bilaterally. of CTEPH is essential since chronic of perfusion defects. [4] As shown These findings were consistent with thromboembolism is potentially in this case, chest CTA helped the CTEPH. There were no features of curable using PTE. radiologist to assess the presence any COVID-19 sequelae. Lately, the role of CT in the diagnostic of CT features of a chronic PE and approach of PH etiology has been to identify a dilation of pulmonary The patient was transferred to evolving and the growing importance arteries and right ventricular the national reference center for of modern CT techniques in the diag- dysfunction secondary to PH. therapeutic decision. Owing to the nosis of CTEPH has been reinforced. CTEPH was clearly assessed as the presence of proximal obstruction of etiology of PH, which helped the the pulmonary arterial circulation This case was performed with physician to make a proper treatment NAEOTOM Alpha®, a newly devel- plan for the patient. 30 Photon-counting CT case reports Pulmonology · Case report References 1a 2a [1] Martine Remy-Jardin, et al. Imaging of Pulmonary Hypertension in Adults: A Position Paper from the Fleischner Society. Radiology 2021; 298:531–549. [2] Sadjad Riyahi, et al. Pulmonary Embolism in Hospitalized Patients with COVID-19: A Multicenter Study. Radiology 2021; 301:E426–E433. [3] Thomas Flohr, et al. Photon-counting CT review. Physica Medica 79 (2020) 126–136. 1b 2b [4] Nakazawa T, Watanabe Y, Hori Y, et al. Lung perfused blood volume images with dual-energy computed tomography for chronic thromboembolic pulmonary hypertension: correlation to scintigraphy with single-photon emission computed tomography. J Comput Assist Tomogr 2011; 35(5):590–595. 1c 2c The statements by customers of Siemens 1 An axial image shows proximal filling 2 Axial (Fig. 2a), coronal (Fig. 2b) Healthineers described herein are based on defects in the PA of the right middle and sagittal (Fig. 2c) MPR images results that were achieved in the customer’s lobe as well as in the anterior show a pattern of mosaic perfusion unique setting. Because there is no “typical” segmental PA of the left lower lobe in both lungs. hospital and many variables exist (e.g., hospital (Fig. 1a, arrows). A coronal MPR image size, case mix, level of IT and/or automation shows a “web” sign in the segmental adoption) there can be no guarantee that PA of the right upper lobe (Fig. 1b, other customers will achieve the same results. arrow). A significant enlargement The products/features (mentioned herein) are of the right atrium and moderate not commercially available in all countries. enlargement of the right ventricle Their future availability cannot be guaranteed. are also seen (Fig. 1c). * 510k pending. Photon-counting CT case reports 31 Case report · Pulmonology 3a 4a Examination Protocol Scanner NAEOTOM Alpha Scan area Thorax Scan mode QuantumPlus Scan length 350 mm Scan direction Cranio-caudal Scan time 1 s Tube voltage 120 kV Effective mAs 56 mAs Dose modulation CARE Dose4D 3b 4b CTDIvol 4.3 mGy DLP 168 mGy*cm Rotation time 0.25 s Pitch 1.5 Slice collimation 144 x 0.4 mm Slice width 1.0 mm Reconstruction 1.0 mm increment Reconstruction Qr40, kernel QIR3 Spectral LungPBV 3c 4c reconstruction Contrast 400 mg/mL Volume 60 mL + 40 mL saline Flow rate 4 mL/s Start delay Bolus tracking triggered at 100 HU in the ascending aorta + 5 s 3 Cinematic VRT images show the 4 Sagittal (Figs. 4a & 4c) and coronal dilation of the central PA, tapering views (Fig. 4b) of the LungPBV image and pruning of the peripheral PA, show multiple peripheral wedge- as well as a dilated bronchial artery shaped perfusion defects bilaterally. (arrow, Fig. 3b). 32 Photon-counting CT case reports Pulmonology · Case report Severe emphysema treated with endobronchial valves Prof. Martine Rémy-Jardin, MD1, Ph.D.; Prof. Jacques Rémy, MD2 1 Department of Thoracic Imaging, University Centre of Lille, France 2 Department of Radiology, Hospital Center of Valenciennes, France History A 53-year-old male patient, suffering ous low-attenuation areas were seen ing detectors (QuantaMax®), provid- from progressive worsening of bilaterally in both lungs, indicating ing energy-resolved CT data at dyspnea with mild productive cough a heterogeneous emphysema improved spatial resolution, with in- within the context of tobacco distribution. herent spectral information and im- consumption (45 pack-years) over the last decade, was diagnosed EBV treatment had favorable effects proved tissue contrasts, without elec- tronic noise. [5] A low-dose UHR scan with chronic obstructive pulmonary on the patient’s outcome including a reduction of his dyspnea and mode was applied, using a special tin disease (COPD), grade GOLD 3, with severe emphysema and hyper- improved results at the six-minute filter optimizing the X-ray spectrum. walk test. The UHR mode features a slice inflation. The predominance of collimation of 120 x 0.2 mm, in emphysematous lesions in the right which the sub-pixels of the detector upper lobe (RUL) led to the consider- Comments with a size of 0.15 x 0.18 mm2 ation of an endobronchial treatment (at the isocenter) are read out of emphysema by endobronchial Emphysema is a major subtype of individually. There are no physical valve (EBV) deposition – an inter- COPD, a progressive lung disease septa between the pixels, each ventional procedure aiming to reduce characterized by long-term breathing group of 4 x 6 sub-pixels is confined the lung volume in order to improve problems and poor airflow. It cannot by collimator grids. ipsilateral diaphragmatic motion be cured; however, different treat- and subsequently, the patient’s ments are available to help manage This increases the spatial resolution respiratory condition. The EBV the symptoms, e.g., EBV deposition. without degrading the geometric treatment was targeted at the RUL. This treatment has shown favorable dose efficiency of the detector, An ultra-high resolution (UHR) chest effects on patients' outcomes, resulting in an improved anatomic CT was indicated for post-procedural including effective improvements conspicuity in CT imaging at low evaluation. in lung function, exercise tolerance radiation dose. Furthermore, and quality of life. [1] [2] [3] The electronic noise is eliminated by eligibility of EBV treatment requires a setting up a predefined digital Diagnosis thorough analysis of the emphysema threshold for counting X-ray photons The chest CT prior to the EBV deposi- distribution as well as the absence far above the electronic noise floor, which leads to less image noise tion revealed the completeness of of collateral ventilation that could hamper atelectasis of the treated and potentially a reduction of the the right major and minor fissures, radiation dose. As the electronic providing key information to ensure lobe. [4] All these pieces of infor- the absence of collateral ventilation. mation are provided by the chest CT noise is particularly dominant at low X-ray flux, its absence has a CT images, obtained 3 months after examination prior to the procedure. The post-procedural chest CT particular impact on the low-dose EBV deposition, showed three valves deposited in the right apical, posterior validates the correct position of chest CT scanning with improved image quality. Another important and anterior segmental bronchi the deposited valves and provides improvement in chest CT is the enabling obstructions of the corre- analysis of the lobar atelectasis sponding bronchi. An upward and induced by the valves. higher contrast-to-noise ratio (CNR) due to the missing down-weighting anterior displacement of the right This case was performed with of lower energy X-ray photons. In major fissure with complete atelecta- NAEOTOM Alpha®, a newly devel- the image reconstruction process, sis of the RUL was visualized. Numer- oped CT scanner with photon-count- a model based iterative reconstruc- Photon-counting CT case reports 33 Case report · Pulmonology 1a 1b 1c 1 A coronal MPR image of pre-EBV deposition (Fig. 1a) shows low-attenuation areas in both lungs, with a predominant distribution in the RUL, indicating severe emphysema. The RUL is seen completely collapsed in the post EBV deposition image (Fig. 1b). A VRT image (Fig. 1c) shows the interrupted bronchus of the RUL (arrow). tion approach – Quantum Iterative Reconstruction (QIR) – is applied for further image noise reduction. Owing to the reduced image 2a 2b noise, even low-dose UHR images (0.2 mm) can be used for three- dimensional reconstructions, such as cinematic volume rendering technique (cVRT), demonstrating a photo-realistic visualization of anatomical details. As shown in this case, chest CT imaging plays an important role in patient selection prior to an EBV treatment and follow-up evaluation after the treatment. High-resolution (HR) images are traditionally associ- ated with higher dose necessary for image noise reduction in thinner slices, but now, UHR images can be 2 A sagittal MPR image of the pre-EBV deposition (Fig. 2a) shows the completeness of acquired with low dose providing the right major and minor fissures. The same view of the post EBV deposition (Fig. 2b) shows the upward and anterior displacement of the right major fissure with complete the level of image details needed. atelectasis of the RUL (arrowheads). 34 Photon-counting CT case reports Pulmonology · Case report 3a 3b 3c 3d 3e 3f 3 cVRT images (Figs. 3a–3c) and oblique MPR images (Figs. 3d–3f) show three valves deposited in the right apical, posterior and anterior segmental bronchi and a completely collapsed RUL. Both cVRT and MPR views are reconstructed using 0.2 mm low-dose UHR images. References [1] M D. J. Slebos, et al. Endobronchial Valves Examination Protocol for Endoscopic Lung Volume Reduction: Best Practice Recommendations from Expert Panel on Endoscopic Lung Volume Scanner NAEOTOM Alpha Reduction. Respiration 2017; Scan area Thorax 93:138–150. DOI: 10.1159/000453588. Scan mode Quantum HD + Sn [2] K. Klooster, et al. One-Year Follow-Up Scan length 355 mm after Endobronchial Valve Treatment in Patients with Emphysema without Scan direction Cranio-caudal Collateral Ventilation Treated in the STELVIO Trial. Respiration 2017; Scan time 3.7 s 93:112–121. DOI: 10.1159/000453529. Tube voltage Sn140 kV [3] M Patel, et al. Meta-analysis and Effective mAs 55 mAs Systematic Review of Bronchoscopic Lung Volume Reduction Through Dose modulation CARE Dose4D Endobronchial Valves in Severe Emphy- sema. J Bronchology Interv Pulmonol. CTDIvol 1.98 mGy 2022 Jul 1; 29(3):224-237. DLP 73.1 mGy*cm doi: 10.1097/LBR.0000000000000872. Epub 2022 May 27. Rotation time 0.25 s Pitch 1.0 The statements by customers of Siemens [4] Global Initiative for Chronic Obstructive Healthineers described herein are based on Lung Disease. Global strategy for the Slice collimation 120 x 0.2 mm results that were achieved in the customer’s diagnosis, management, and prevention unique setting. Because there is no “typical” of chronic obstructive pulmonary Slice width 0.2 mm hospital and many variables exist (e.g., hospital disease (2022 report). size, case mix, level of IT and/or automation Reconstruction 0.2 mm https://goldcopd.org/2022-gold-reports-2. adoption) there can be no guarantee that increment other customers will achieve the same results. [5] Thomas Flohr, et al. Photon-counting Reconstruction BI60, QIR4 The products/features (mentioned herein) are CT review. Physica Medica 79 (2020) kernel not commercially available in all countries. 126–136. Their future availability cannot be guaranteed. Photon-counting CT case reports 35 Case report · Neurology Cerebrospinal fluid-venous fistula detected in a patient with a long history of headaches Fides Regina Schwartz, MD; Timothy Amrhein, MD Department of Radiology, Duke University Health System, North Carolina, USA History A 58-year-old female patient with a CVF arising from the right T5 level, nerve root sleeve, with the fistulous 10-year history of migraine, tinnitus evidenced by contrast in an adjacent connection frequently originating and orthostatic headache, was paraspinal vein (Fig. 1b). Additional from the nerve root sleeve itself, as referred to the department of neuro- clarity was gained from the iodine seen in this case. While some case se- radiology for evaluation. Symptoms map (Fig. 1c) as well as the 3D ries have suggested a possible lateral- were typical for spontaneous intra- images created by cinematic volume ity preference, the evidence for such cranial hypotension (SIH) and a rendering technique (cVRT, Fig. 1d). a predilection is not strong, and CVFs brain MRI with i.v. contrast material Identification and localization of can occur on either side of the spine. confirmed the diagnosis, demonstrat- this CVF allowed the patient to be ing dural enhancement, venous referred to neurosurgery for definitive Unlike dural tears, which were the distension, and brain sagging. A treatment with surgical ligation. first described cause of intracranial prior attempt at finding the causative Surgery was successful resulting in hypotension, most CVFs do not lead spinal cerebrospinal fluid-venous resolution of her symptoms and to the pooling of CSF in the epidural fistula (CVF) three years earlier was normalization of brain MRI findings space. This lack of epidural fluid unsuccessful. CT myelography (CTM) of SIH. accumulation makes it challenging was performed on a dual source to detect CVFs through conventional photon-counting CT (PCCT), anatomical imaging. Instead, the NAEOTOM Alpha®, using an ultra- Comments use of a myelographic contrast agent high resolution (UHR) scan mode CVFs represent abnormal connections specific to CSF is necessary for their (Quantum HD) to identify and between the spinal subarachnoid visualization. Consequently, standard localize the CVF prior to a definitive space and adjacent paraspinal veins. spine MRI, commonly employed for treatment. These anomalous connections allow detecting epidural CSF leaks, is not for uncontrolled outflow of cerebro- effective for identifying CVFs and Diagnosis spinal fluid (CSF) into the venous CTM has emerged as a better imaging system, ultimately leading to intra- modality. The traditional challenge Previous CTM images, acquired at cranial hypotension. Although CVFs with EID CT scanners is to improve 0.625 mm slice thickness on an have been recognized only recently, the spatial resolution without energy-integrating-detector (EID) CT, they have rapidly emerged as a increasing radiation dose or accept- had revealed prominent spinal nerve common underlying cause of spinal ing excessive image noise. This root sleeves at multiple levels, how- CSF leaks in patients with SIH, has become possible with the intro- ever, was unable to identify the CVF particularly in cases where initial duction of PCCT. It is feasible to (Fig. 1a). For this new exam, UHR spinal imaging fails to reveal any acquire UHR images at full dose CTM images were acquired at 0.2 mm obvious leaks. efficiency without the application slice thickness on PCCT in left lateral of additional hardware like combs or and right lateral decubitus, and prone CVFs are most frequently found in grids to reduce the detector aperture position at rest, end-inspiration breath the thoracic spine, particularly in the at the cost of reduced dose efficiency hold, and during Valsalva maneuver, lower levels from T7 to T12. However, as this would be the case with EID CT. after the injection of 10 mL of they can also occur in upper thoracic As shown in this case, the CVF was iopamidol (300 mg/mL) into the sub- levels, as presented in this case. not visible on the previous scan arachnoid space via lumbar puncture. Fistulas in the upper lumbar or lower conducted on an EID CT with the The UHR images in end-inspiration cervical levels are less common. CVFs traditional thin-slice approach; but revealed the causative sub-millimeter are anatomically associated with a it was successfully identified now on 36 Photon-counting CT case reports Neurology · Case report 2a1 1b 1c 1d * * * * 1 An axial image, acquired at 0.625 mm on an EID CT at the level of T5 (Fig, 1a), shows a prominent nerve root sleeve visible to the right of the spinal canal (asterisk). A CVF is not apparent. A UHR image, acquired at 0.2 mm on PCCT (Fig. 1b) shows a prominent nerve root sleeve (asterisk) and a visible CVF at the same level (arrow). An iodine map (Fig. 1c, 0.4 mm) and a thin slab cVRT image (Fig. 1d) show the CVF (arrows) at the same location. the PCCT with its inherent UHR mode for PCCT, providing UHR morphologi- The patient was relieved from a long at 79% of radiation dose reduction cal images and the spectral images history of headaches. (8.6 mGy with PCCT vs. 41.3 mGy with chemical composition infor- with EID CT). A model-based iterative mation (iodine map) from the same The statements by customers of Siemens reconstruction approach – Quantum data. In this case, the iodine maps Healthineers described herein are based on results that were achieved in the customer’s Iterative Reconstruction (QIR) – is generated from the spectral informa- unique setting. Because there is no “typical” applied in the image reconstruction tion gave additional confidence in hospital and many variables exist (e.g., hospital process for further image noise visualizing the CVF identified in the size, case mix, level of IT and/or automation adoption) there can be no guarantee that reduction. It is worth noting that the UHR images. The improved visuali- other customers will achieve the same results. combination of UHR images and zation helps the physicians make a spectral information (albeit at some- confident diagnosis and facilitates an The products/features (mentioned herein) are not commercially available in all countries. what reduced resolution) is unique appropriate treatment planning. Their future availability cannot be guaranteed. Examination Protocol Scanner NAEOTOM Alpha Scan area Spine DLP 341 mGy cm Scan mode UHR (Quantum HD) Rotation time 0.5 s Scan length 354 mm Pitch 0.85 Scan direction Caudo-Cranial Slice collimation 120 x 0.2 mm Patient position FFDR (Feet First Slice width 0.2 mm Decubitus Right) Reconstruction increment 0.2 mm Scan time 7.6 s Reconstruction kernel Br48u, QIR 4 Tube voltage 140 kV Contrast iopamidol Tube current 74 mAs (300 mg/mL) Dose modulation CARE Dose4D Volume 10 mL CTDIvol 8.58 mGy Flow rate Manual injection Photon-counting CT case reports 37 Case report · Otology Stapes prosthesis dislocation Hunor Sükösd, MD; Éva Juhász, RT Medical Imaging Centre, Semmelweis University, Budapest, Hungary History 1a 1b A 74-year-old female patient, with a history of bilateral stapedectomy and stapes prosthesis insertion 10 years ago, came to the hospital complaining of a progressive, worsening conductive hearing loss on the left side for over the past 2 years. A CT examination using a ultra-high resolution (UHR) scan 1c 1d mode was performed for evaluation. Diagnosis CT images showed a piston wire prosthesis (PWP) on each side. The right PWP was normally positioned, with one end hooked onto the long process of the incus and the other attached to the oval window. A second PWP was also seen inside the 1 Oblique MPR images show a 3 mm long PWP on each side (Figs. 1a & 1b). The right right middle ear below the auditory PWP (Fig. 1a, arrow) is in a normal position, and the left PWP (Fig. 1b, dotted arrow) is dislocated. Otosclerosis is visualized bilaterally with subtle lucency in the bones ossicles. The left PWP was dislocated, near the cochlea (Figs. 1c & 1d, arrows). with its loop slipped out of the long process of the incus and detached, from the other end, from the oval can affect the movement of the 120 x 0.2 mm is applied in which window. Otosclerosis was visualized stapes causing conductive hearing the sub-pixels of the detector, with bilaterally. loss. This may be corrected by a size of 0.15 x 0.18 mm2 (at the stapedectomy, a surgical replace- isocenter), are read out individually. Subsequently, the patient was ment of the stapes with a prosthesis. There are no physical septa between scheduled for revision surgery on High resolution CT scans of the the pixels, each group of 4 x 6 sub- the left. The second PWP on the temporal bones have been routinely pixels is confined by collimator grids. right was considered a failed insertion performed for both pre-surgery attempt (10 years ago) that was diagnosis as well as for post-surgery Therefore, the full radiation dose accidentally left there, and a revision follow-up. The prosthetic position efficiency of the detector is pre- in the middle ear can be determined served in UHR mode. Furthermore, tympanoplasty for retrieval was not planned as the patient had no with high resolution CT. However, electronic noise is eliminated by set- complaint at all on that side. the thin metallic wires are difficult to ting up a predefined digital threshold detect due to volume averaging. [1] for counting X-ray photons far above the electronic noise floor. A refined Comments This case is performed on NAEOTOM iterative reconstruction technique Alpha®, a newly developed Dual (Quantum Iterative Reconstruction QIR) The stapes is the innermost bone Source CT scanner with photon- is used to efficiently reduce image of the auditory ossicles in the middle counting detectors (QuantaMax®), noise at ultra-high resolution without ear. It has a footplate which seals the providing energy-resolved CT data negatively affecting image sharpness oval window and conducts vibrations at improved spatial resolution, with- or image noise texture. This combi- to the cochlea. Otosclerosis is an out electronic noise. [2] A UHR mode nation – image noise reduction and abnormal bone remodeling which featuring a slice collimation of ultra-thin image slices at full dose 38 Photon-counting CT case reports Otology · Case report 2a 2b 2 cVRT images show the PWP, the auditory ossicles and the cochlea on both sides. The right PWP (Figs. 2a, 2c, 2e & 2g, arrows) is in a normal position, with one end hooked onto the long process of the incus and the other attached to the oval window. A second right PWP (arrowheads) is also seen inside the middle ear below the auditory ossicles. The left PWP (Figs. 2b, 2d, 2f & 2h, dotted arrows) is dislocated, with its loop slipped out of the long 2c 2d process of the incus and detached, from the other end, from the oval window. Note that the axial images used for cVRT creation are slices reconstructed at 0.2 mm with a very sharp kernel of Hr84. 2e 2f Examination Protocol Scanner NAEOTOM Alpha 2g 2h Scan area Temporal Bone Scan mode Quantum HD Scan length 60 mm Scan direction Caudo-cranial Scan time 1.5 s Tube voltage 120 kV Effective mAs 91 mAs efficiency – allows not only for References improved anatomic conspicuity, [1] D. Pickuth et al. Vertigo after stapes Dose modulation CARE Dose4D due to increased spatial resolution, surgery: the role of high resolution CT. but also for a photo-realistic three- The British Journal of Radiology, 73 CTDIvol 15.5 mGy (2000), 1021–1023. dimensional visualization of ana- DLP 120 mGy*cm tomical details using cinematic [2] Thomas Flohr, et al. Photon-counting volume rendering technique (cVRT). CT review. Physica Medica 79 (2020) Rotation time 0.5 s As shown in this case, even images 126–136. Pitch 0.85 reconstructed at 0.2 mm with a very The statements by customers of Siemens sharp kernel of Hr84, can be used Healthineers described herein are based on Slice collimation 120 x 0.2 mm results that were achieved in the customer’s to render incredible details of the unique setting. Because there is no “typical” Slice width 0.2 mm only 3 mm long PWP. CT findings hospital and many variables exist (e.g., hospital clearly show the prosthesis disloca- size, case mix, level of IT and/or automation adoption) there can be no guarantee that Reconstruction 0.1 mm tion, explaining the progressive other customers will achieve the same results. increment hearing loss, and assist the otologist in making an appropriate surgical The products/features (mentioned herein) are Reconstruction Hr84 not commercially available in all countries. revision plan for the patient. kernel Their future availability cannot be guaranteed. Photon-counting CT case reports 39 Case report · Otology Congenital cholesteatoma Hunor Sükösd, MD; Éva Juhász, RT Medical Imaging Centre, Semmelweis University, Budapest, Hungary History A 7-year-old girl suffering from bi- CT diagnosis. A diagnostic tympano- improve spatial resolution at full lateral progressive conductive hearing plasty was considered on the other dose-efficiency. [3] By using an loss, worse on the left side, was side later on, if the symptoms optimized 70 kV protocol, a very low presented to the hospital. Physical persisted post-operatively. dose-length product (DLP) of only examination was unremarkable 92.3 mGy*cm could be achieved, on both eardrums. There were no signs of a middle ear infection Comments substantially lower than the typical DLPs of 200-400 mGy*cm for this present. A CT examination was Congenital cholesteatomas are type of examination. Photon- indicated for further assessment of inclusion cysts of the ectoderm counting CT enables UHR scanning the middle ear structures. An ultra- and are comprised of keratin debris at low radiation dose without high resolution (UHR) scan mode and cholesterol. They are one of the substantial increase in image noise, (Quantum HD) was performed on more common causes of pediatric since UHR scan data are acquired a dual source photon-counting CT conductive hearing loss besides otitis at full dose efficiency without (NAEOTOM Alpha®). media with effusion. [1] If undiag- additional combs or grids to reduce nosed, cholesteatomas can lead to the detector aperture. Image noise Diagnosis the vast destruction of the middle is further reduced by using a refined ear structures and permanent model based iterative reconstruction UHR CT images showed a soft tissue damage to the hearing apparatus. approach (Quantum Iterative mass in the left middle ear, extending Early diagnosis is essential to prevent Reconstruction, QIR). The UHR into the mastoid antrum. Erosion of extensive surgery and preserve images can even be used as input the long process of the incus and the hearing. [2] However, most children for creating a photo-realistic three- stapes were seen. The eardrum and are asymptomatic and frequently dimensional demonstration of the the scutum were intact and the resist attempts to conduct a thorough anatomical details, using cinematic Prussak’s space was free. No effusion examination. A pre-operative CT scan volume rendering technique (cVRT), or developmental anomalies were is essential in defining the extent of assisting the otologist in setting present. CT findings were consistent existing pathology, assessing the up an appropriate surgical plan with congenital cholesteatoma, bony labyrinth and hearing ossicles, for the patient. Potsic stage IV. There were no as well as planning potential surgery. pathological findings visualized on This especially requires high spatial the right side. An MRI examination resolution for evaluating the detailed References was performed to confirm the structures and low dose for pediatric [1] David Walker; Michael J. Shinners. diagnosis which showed increased patients. Congenital Cholesteatoma. diffusion restriction of the mass, This case is performed on a dual Pediatr Ann. 2016;45(5):e167-e170. characterizing a cholesteatoma. source photon-counting CT No abnormalities were visualized (NAEOTOM Alpha) using an UHR [2] M.A. El-Bitar et al. Congenital middle on the right side in the MRI. mode, acquiring scan data at ear cholesteatoma: need for early recognition – role of computed 120 x 0.2 mm collimation and tomography scan. International Journal As the symptoms were worse on the reconstructing images at 0.2 mm of Pediatric Otorhinolaryngology (2003) left side, and there were no patho- slice width with a very sharp bone 67, 231-235. logical findings on the right side, the kernel (Hr84). In this mode, each patient was primarily treated for the sub-pixel of the photon-counting [3] Thomas Flohr, et al. Photon-counting CT review. Physica Medica 79 (2020) left side. Surgical findings confirmed detector is read-out individually to 126–136. 40 Photon-counting CT case reports Otology · Case report 1a 1b 1 Axial images (Figs. 1a & 1b) and coronal MPR images (Figs. 1c & 1d) show a soft tissue mass in the left middle ear, eroding the long process of the incus and the stapes. The Prussak’s space (Fig. 1d, arrow) is free and the scutum was intact. No remarkable findings 1d on the right side. 1c cVRT images (Figs. 1e & 1f) show a 3D view of bilateral ossicles – normal on the right and eroded on the left. Note that the input images for cVRT creation are the UHR images reconstructed at 0.2 mm with a very sharp 1e 1f kernel of Hr84. Examination Protocol Scanner NAEOTOM Alpha Scan area Temporal bone DLP 92.3 mGy*cm Scan mode Quantum HD Rotation time 0.5 s The statements by customers of Siemens Healthineers described Scan length 53.8 mm Pitch 0.85 herein are based on results that were Scan direction Caudo-cranial achieved in the customer’s unique Slice collimation setting. Because there is no “typical” 120 x 0.2 mm Scan time 1.3 s hospital and many variables exist (e.g., hospital size, case mix, level Tube voltage 70 kV Slice width 0.2 mm of IT and/or automation adoption) there can be no guarantee that Effective mAs 340 mAs Reconstruction 0.2 mm other customers will achieve the same results. Dose modulation increment CARE Dose4D The products/features (mentioned CTDIvol 13 mGy Reconstruction Hr84, QIR3 herein) are not commercially (16 cm phantom) kernel available in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 41 Case report · Gastroenterology Small bowel infarction secondary to an acquired diaphragmatic hernia Nicholas H. Shaheen, MD1; Maxwell Stroebel, MD1; Cynthia Welsh, MD2; Barry Gibney, DO3; Andrew D. Hardie, MD1 1 Department of Radiology and Radiological Sciences, The Medical University of South Carolina, Charleston, SC, USA 2 Department of Pathology, The Medical University of South Carolina, Charleston, SC, USA 3 Department of Surgery, The Medical University of South Carolina, Charleston, SC, USA History A 75-year-old male patient, with a bowel infarction was made, and the interpreted as normal mucosal history of esophagectomy 10 years patient was taken rapidly to surgery enhancement in viable bowel. ago, presented to the emergency for small bowel resection. Pathologi- However, its presence in the VNC department with an acute onset of cal evaluation on the resected bowel images and absence in the iodine epigastric pain radiating to the left confirmed complete bowel necrosis maps characterize an infarction. upper quadrant, chest pain, obsti- with hemorrhagic blood products The added spectral information pation and numerous episodes of throughout all bowel layers and improves reader confidence, and vomiting. On physical examination, sloughing of the mucosa. The patient then, taking into account the clinical the patient was diaphoretic and tachy- recovered with good outcome. and laboratory findings, a rapid cardic, showing guarding in the upper diagnosis can be made which is abdomen. Laboratory results revealed Comments essential for the patient to receive a lactate level of 3.0 mmol/L, an prompt treatment. The CT scan was estimated GFR of > 60 and a WBC of Bowel infarction refers to vascular performed with NAEOTOM Alpha®, 11. A CT examination of the abdomen compromise of portions of the bowel. a newly developed CT scanner with and pelvis with contrast was immedi- It can occur secondarily to an photon-counting detectors. It pro- ately performed for evaluation. acquired diaphragmatic hernia in vides energy-resolved CT data with patients with prior surgery due to a high spatial resolution, without Diagnosis altered anatomy, such as this case. electronic noise. [1] The initial clinical presentations in- CT images revealed multiple dilated cluding physical exam and laboratory loops of small bowel herniating into abnormalities are usually nonspecific. 1 the thoracic cavity through a defect However, the progress from an initial in the left hemidiaphragm. A thin rim necrosis of the bowel wall to a final of hyperdensity within the wall of sepsis and multiorgan failure can the herniated bowel loops was seen go rapidly. Treatment is often in the images reconstructed conven- surgical and imaging is relied upon tionally, indeterminate of mucosal for rapid diagnosis. In recent years, enhancement (suggesting no isch- CT has largely replaced conventional emia) or hemorrhage within the sub- angiography due to rapid access and mucosa (suggestive of infarction). accuracy. On CT imaging, ischemic In the assessment of spectral imaging segments of bowel are often found data, a complete lack of enhance- to have a different density and ment within the herniated loops of enhancement compared to non- bowel was shown in the iodine maps, ischemic segments. However, the compatible with infarction. The hy- subtlety of positive image findings perdensity in the bowel wall was pres- may go underappreciated and can ent in the virtual non-contrast (VNC) lead to unnecessary delay or even images, suggestive of hemorrhage in misdiagnosis. In this case, the thin 1 the submucosa. With this added spec- A coronal view of a VRT image shows rim of hyperdensity demonstrated herniated loops of small bowel tral information, a diagnosis of small in the bowel wall could have been (arrow) into the left thoracic cavity. 42 Photon-counting CT case reports Gastroenterology · Case report 2a 2b 2c 2 A contrast enhanced axial image (Fig. 2a) shows a thin rim of hyperdensity within the wall of the herniated bowel loops (arrows), which are also seen in the VNC image (Fig. 2b), but not seen in the iodine map (Fig. 2c), suggesting submucosal hemorrhage, compatible with infarction. The availability of spectral imaging may overcome the traditional short- Reference data in routine scans is one of the comings of conventional CT in detect- [1] Thomas Flohr, Martin Petersilka, major improvements in workflow. ing bowel infarction by adding io- Andre Henning, Stefan Ulzheimer, Conventional CT image reading can dine-sensitive information, enabling Jiří Ferda, Bernhard Schmidt. Photon-counting CT review. be freely switched to spectral image the differentiation of hemorrhage Physica Medica 79 (2020) 126–136. reading with just one mouse click, from true contrast-material uptake, making the assessment of diagnostic i.e., blood perfusion, with distinctive information more efficient and fast. image findings. As presented in this case, spectral CT Examination Protocol Scanner NAEOTOM Alpha Contrast 350 mg/mL Scan area Abdomen/Pelvis Volume 94 mL + 39 mL saline Scan mode QuantumPlus Flow rate 3 mL/s Scan length 426 mm Start delay Bolus tracking triggered Scan direction Cranio-caudal at 100 HU in the abdominal aorta + 5 s Scan time 7 s Tube voltage 120 kV Effective mAs 161 mAs Dose modulation CARE Dose4D CTDIvol 12.6 mGy DLP 584 mGy*cm Rotation time 0.5 s Pitch 0.8 Slice collimation 144 x 0.4 mm The statements by customers of Siemens Healthineers described herein are Slice width 3 mm based on results that were achieved in the customer’s unique setting. Because Reconstruction increment 3 mm there is no “typical” hospital and many variables exist (e.g., hospital size, case mix, level of IT and/or automation adoption) there can be no guarantee that Reconstruction kernel Br36f other customers will achieve the same results. Spectral reconstruction VNC, iodine map The products/features (mentioned herein) are not commercially available in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 43 Case report · Orthopedics Scaphoid fracture only seen in CT Jan Baxa, MD, Ph.D. Department of Imaging Methods, University Hospital Pilsen and Medical Faculty of Charles University, Pilsen, Czech Republic History Comments A 14-year-old girl presented herself Scaphoid fractures are the most data acquisition is feasible at full to the emergency department due common amongst the carpal bones. dose efficiency without additional to a fall onto her outstretched right Missed or inconclusive diagnoses combs or grids to reduce the detector hand. A radiograph was performed on wrist radiographs may cause a aperture at the cost of reduced dose with unremarkable findings. As, delay of initial treatment. This can efficiency and increased radiation two weeks later, the pain and the lead to nonunion, and ultimately, dose as in previous equipment. movement limitations in the right loss of wrist motion and eventual A model-based iterative reconstruc- wrist persisted, another radiograph arthritis. CT imaging plays an tion approach – Quantum Iterative was performed but this only revealed important role for improved accuracy Reconstruction (QIR) – is applied an equivocal result. A CT scan was in the diagnosis, as well as in the in the image reconstruction process requested for further evaluation, follow-ups of a scaphoid fracture. for further image noise reduction, using an ultra-high resolution (UHR) It provides detailed information resulting in a sharp visualization mode on a photon-counting CT using multiplanar reformation (MPR) of trabecular bone structures with (PCCT) scanner NAEOTOM Alpha®. as well as 3D reconstructions such low image noise. PCCT with UHR as cinematic volume rendering scan data acquisition can be very Diagnosis technique (cVRT). The traditional beneficial in minor injuries of challenge with conventional CT peripheral bones, particularly when UHR CT images showed an oblique scanners is to improve the spatial the radiograph is inconclusive, and fracture line in the scaphoid. Neither resolution without increasing the clinical symptoms are atypical. dislocation nor distraction were radiation dose or accepting excessive As shown in this case, the fracture seen. There were evident signs of image noise. This has become line that is missed on the radiograph increased density, or even sclerosis, possible with the introduction of is clearly depicted on the UHR CT in the fissure, suggesting partial PCCT, especially when using the images. Because of their low image healing. Based upon the CT findings, UHR mode. Images are acquired noise, these images are also used the patient was treated with an on a dual source PCCT (NAEOTOM as input to create cVRT images for external splint fixation. Three weeks Alpha) at 0.2 mm slice width and a lifelike 3D visualization of the later, a follow-up radiograph was reconstructed with a very sharp scaphoid, helping the physicians performed with evidence of advanced kernel of Br84, using a large image to make an optimal treatment healing without complication. matrix of 1024 x 1024. UHR scan decision. Examination Protocol Tube voltage 120 kV Slice collimation 120 x 0.2 mm Scanner NAEOTOM Alpha Effective mAs 40 mAs Slice width 0.2 mm Scan area Wrist Dose modulation CARE Dose4D Reconstruction 0.1 mm Scan mode Quantum HD CTDIvol 3.2 mGy increment Scan length 96.2 mm DLP 56.1 mGy*cm Reconstruction Br84, QIR 3 kernel Scan direction Cranio-caudal Rotation time 0.5 s Reconstruction 1024 x 1024 Scan time 2.4 s Pitch 0.85 matrix 44 Photon-counting CT case reports Orthopedics · Case report 1a 1b 1 UHR CT images (Figs. 1a & 1b) and cVRT images (Figs. 1c & 1d) show an oblique fracture line (arrows) in the scaphoid without dislocation or distraction. Note that the input images for cVRT creation are reconstructed at 0.2 mm, with a very sharp kernel of Br84 and an image matrix of 1024 x 1024. 1c 1d 2a 2b 2 cVRT images (Figs. 2a & 2c) and UHR CT images (Figs. 2b & 2c) show the fracture line in the scaphoid. Increased density is seen in the fissure (arrow) suggesting partial healing. Note that the input images for cVRT creation are reconstructed at 0.2 mm, with a very sharp kernel of Br84 and an image matrix of 1024 x 1024. 2c 2d The statements by customers of Siemens Healthineers described herein are based on results that were achieved in the customer’s unique setting. Because there is no “typical” hospital and many variables exist (e.g., hospital size, case mix, level of IT and/or automation adoption) there can be no guarantee that other customers will achieve the same results. The products/features (mentioned herein) are not commercially available in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 45 Case report · Orthopedics Osteochondritis dissecans of the capitellum Ronald Booij, Ph.D.; Prof. Edwin Oei, MD, Ph.D. Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands History A 13-year-old female patient, a adolescent athletes. [1] In the elbow, combs or grids to reduce the detector gymnast, with left elbow complaints it typically affects the humeral aperture, and image noise is further for the past 18 months, presented capitellum. Early recognition and reduced by a refined model based herself to our hospital. A radiograph appropriate intervention may protect iterative reconstruction approach of the elbow showed a suspicious adolescents from fragmentation of (Quantum Iterative Reconstruction, osteochondritis dissecans (OCD) of the OCD lesion and the development QIR). The low image noise even the capitellum. To further evaluate of irreversible cartilage damage. It is enables the use of the UHR images the dimension of the lesion and important to differentiate between for cinematic volume rendering the possible existence of loose frag- stable and unstable OCD lesions, technique (cVRT), providing an ments, an ultra-high resolution (UHR) hereby is a CT considered more excellent photo-realistic 3D visuali- scan mode (Quantum HD) on a sensitive than a radiograph, to deter- zation and facilitating surgery photon-counting CT (PCCT) scanner mine the best treatment option. [2] planning. Potentially, image noise (NAEOTOM Alpha®) was requested. An unstable lesion would require a reduction also leads to a reduction surgical approach, and prior to that, of the radiation dose, which is Diagnosis it would be essential to acquire important especially for young detailed diagnostic information, such patients. As shown in this case, The UHR CT images showed a cortical as the lesion size, the stability and the combination of improved defect at the capitulum of the left viability of the lesion fragment and spatial resolution with reduced humerus, with an approximate size the number of present loose bodies, image noise, provided by UHR of 9.2 mm (coronal) x 9.8 mm for surgical planning. imaging with PCCT, greatly benefits (sagittal) x 4.1 mm (depth) on the This case is performed on a the musculoskeletal imaging. medial side. There were two loose fragments – one was about 5.1 mm NAEOTOM Alpha, a newly developed in size, next to the capitulum, and dual source PCCT scanner, providing the other was about 6.2 mm in size, energy-resolved CT data at improved References seen dorsally on the lateral side of spatial resolution, without electronic [1] an Bergen CJ, van den Ende KI, the olecranon. There were no signs noise. [3] UHR images are acquired Ten Brinke B, Eygendaal D. of any focal osseous abnormalities at 0.2 mm slice width and recon- Osteochondritis dissecans of the elsewhere, nor evidence of focal structed using a very sharp kernel capitellum in adolescents. World J (Br89) with a 2% value of the Orthop. 2016 Feb 18;7(2):102-8. muscle abnormalities. The trabecula- doi: 10.5312/wjo.v7.i2.102. PMID: tion of the radial head was normal. modulation transfer function of 31 lp/cm. This provides improved 26925381; PMCID: PMC4757654. CT findings suggested an OCD focus visualization of the cortical and [2] van den Ende KIM, Keijsers R, van den at the capitellum of the left humerus trabecular bone microarchitecture, Bekerom MPJ, Eygendaal D. Imaging and with two loose bone fragments, enhancing the diagnostic confidence classification of osteochondritis dissecans demonstrating an unstable lesion. of the radiologists. Traditionally, of the capitellum: X-ray, magnetic Subsequently, the patient was with conventional CT, UHR images resonance imaging or computed scheduled for arthroscopic surgery. tomography? Shoulder Elbow. 2019 are associated with higher image Apr;11(2):129-136. noise and require higher radiation doi: 10.1177/1758573218756866. Comments dose. However, PCCT enables UHR Epub 2018 Feb 13. PMID: 30941202; scanning without substantial PMCID: PMC6415488. OCD is a disorder of the articular increase in image noise, because cartilage and subchondral bone [3] Thomas Flohr, et al. Photon-counting UHR scan data are acquired at full CT review. Physica Medica 79 (2020) which most commonly occurs in dose efficiency without additional 126–136. 46 Photon-counting CT case reports Orthopedics · Case report 1a 1b 1c 1 MPR images (Figs. 1a, 1d & 1g) and cVRT images (Figs. 1b, 1c, 1e, 1f, 1h & 1i), reconstructed in 3D views, show a cortical defect at the capitulum of the left humerus with two loose fragments – one next to the capitulum (arrows), and the other seen dorsally on the lateral side of the olecranon (dotted arrows). The trabeculation of the radial head shows normal structures. Note that the input images for cVRT 1d 1e 1f creation are reconstructed with 0.2mm slice thickness and a very sharp kernel of Br89. 1g 1h 1i Examination Protocol Scanner NAEOTOM Alpha Scan area Left elbow CTDIvol 4.5 mGy The statements by customers of DLP 50.8 mGy*cm Siemens Healthineers described Scan mode Quantum HD herein are based on results that were Scan length 103 mm Rotation time 0.5 s achieved in the customer’s unique setting. Because there is no “typical” Pitch 0.55 hospital and many variables exist Scan direction Caudo-cranial (e.g., hospital size, case mix, level Scan time 3.8 s Slice collimation 120 x 0.2 mm of IT and/or automation adoption) there can be no guarantee that Slice width 0.2 mm other customers will achieve the Tube voltage 120 kV same results. Reconstruction 0.1 mm Effective mAs 56 mAs increment The products/features (mentioned herein) are not commercially Dose modulation CARE Dose4D Reconstruction kernel Br89, QIR3 available in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 47 Case report · Orthopedics FOOSH injury with screw fixation of the scaphoid Ronald Booij, Ph.D.; Prof. Edwin Oei, MD, Ph.D. Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands History A 20-year-old male patient had under- to lunatum-triquetrum distance. CT data at improved spatial resolution, gone surgery with a screw fixation In summary, CT findings suggested without electronic noise. [4] The of the scaphoid after a FOOSH (fall central, discrete bony bridging, with- spatial resolution is improved by on outstretched hand) injury, 5 years out clear consolidation, and screw using an ultra-thin slice collimation ago. A revision surgery of the screw loosening. Subsequently, the patient of 120 x 0.2 mm. Although it is had had to be performed 4 years later, was scheduled for a surgical revision. traditionally known that thin-slice due to non-union of the fracture. images are associated with higher A follow-up CT showed unclear bone Comments image noise and not suitable for structure around the screw with the 3D image rendering, it is shown in presence of metal artifacts. Further Scaphoid fractures due to a FOOSH this case that with PCCT even images evaluation was needed and performed injury are quite common. Non-union acquired at 0.2 mm with low dose using an ultra-high resolution (UHR) of the fracture may remain if the and reconstructed with a very sharp scan mode (Quantum HD) on a newly healing process is compromised kernel of Br89 (with a 2% value of installed photon-counting CT (PCCT) which may then impact the wrist the modulation transfer function scanner (NAEOTOM Alpha®) in our function. There are various techniques of 31 lp/cm) have low image noise. hospital. that can be applied for fracture This is facilitated by UHR scan data fixation, one such is a screw fixation. acquisition at full dose efficiency Diagnosis CT follow-ups are often performed without additional combs or grids to confirm the bony union or non- to reduce the detector aperture, The UHR CT images showed a union, to assess the screw position and further image noise reduction scaphoid fracture with the fixation and to help surgical planning. [1-3] by a refined model based iterative screw in situ. The fracture in the The opportunities of CT imaging reconstruction (Quantum Iterative scaphoid was still largely visible, with are four-fold: high spatial resolution Reconstruction, QIR). Therefore, a sclerotically bordered fracture line. is required to visualize the trabecular UHR images are optimal for a Minimal central bridging was shown; bridging differentiating bony union photo-realistic 3D visualization using however, there was no obvious from non-union; metal artifacts must cinematic volume rendering consolidation. Lucency at the tip of be minimized to allow assessment technique (cVRT). Anatomical details the screw, as well as in various parts of the bone structure around metal such as the trabecular bone structure around the screw, was visualized, implants, confirming or ruling out surrounding the fracture of the signifying screw loosening. The loosening; low radiation dose is scaphoid can be appreciated. Metal screw protruded proximally into the needed to reduce the exposure in artifacts reduction surrounding radiocarpal joint with an impression repeated scans and last but not least, the screw helps the radiologist to of slight usuration of the head of high quality three-dimensional dem- clearly visualize the lucency and the screw into the radius. There were onstrations are helpful to determine confirm the screw loosening with no signs of osteolysis or evidence the intra-scaphoid angle and elements enhanced diagnostic confidence. of migration of the screw. Early of scaphoid collapse for surgical osteoarthritic changes of the radio- planning, as well as for an illustrative Furthermore, the electronic noise carpal and the scaphotrapezio- communication towards clinicians, of a PCCT is eliminated by setting trapezoid (STT) joint were present. but also especially to the patients. up a predefined digital threshold for A slight dorsal tilting of the lunate counting well above the noise floor. was seen with a subtle increase in This case is performed on NAEOTOM As the electronic noise is dominant scapho-lunar distance compared Alpha, a newly developed PCCT at low X-ray flux, its absence has a scanner, providing energy-resolved particular impact on low-dose CT, 48 Photon-counting CT case reports Orthopedics · Case report 1 MPR images (Fig. 1a & 1c) and cVRT 1a 1b images (Fig. 1b & 1d), reconstructed parallel to the screw, show lucency on the tip of the screw and in various parts around the screw, confirming screw loosening. Metal artifact reduction surrounding the screw is remarkable, and the trabecular bone structure surrounding the fracture can be appreciated. The fracture in the scaphoid is still largely visible, with a sclerotically bordered fracture line. such as scanning with an integrated special tin filter. This case was 1c 1d acquired at the initial phase of our learning curve on PCCT, when we were still quite conservative about dose reduction. It didn’t take us long to realize the potential of the scanner we have further reduced the dose – by half (3.5–4 mGy), in our routine scan protocol for wrist imaging, and the image quality remains optimal. Examination Protocol Scanner NAEOTOM Alpha References Scan area Wrist Slice 120 x 0.2 mm [1] Bartuseck M. Injuries to the upper collimation extremity due to falls on outstretched Scan mode Quantum HD hands (FOOSH). J Urgent Care Med. Slice width 0.2 mm February 2018. Available at: Scan length 48.3 mm www.jucm.com/injuries-upper-extremity- Reconstruction 0.1 mm due-falls-outstretched-hands-foosh Scan direction Caudo-cranial increment [2] Nguyen Q, Chaudhry S, Sloan R, Bhoora I, Scan time 3.5 s Reconstruction Br89, QIR3 Willard C. The clinical scaphoid fracture: early computed tomography as a Tube voltage Sn140 kV kernel practical approach. Ann R Coll Surg Engl. 2008 Sep;90(6):488-91. Effective mAs 216 mAs doi: 10.1308/003588408X300948. Epub 2008 Jul 2. PMID: 18598597; Dose CARE Dose4D The statements by customers of Siemens PMCID: PMC2647242. modulation Healthineers described herein are based on [3] Fowler JR, Hughes TB. Scaphoid fractures. CTDIvol 7.8 mGy results that were achieved in the customer’s unique setting. Because there is no “typical” Clin Sports Med. 2015 Jan;34(1):37-50. hospital and many variables exist (e.g., hospital doi: 10.1016/j.csm.2014.09.011. Epub DLP 65.3 mGy*cm size, case mix, level of IT and/or automation 2014 Nov 25. PMID: 25455395. Rotation 0.5 s adoption) there can be no guarantee that other customers will achieve the same results. [4] Thomas Flohr, et al. Photon-counting time The products/features (mentioned herein) are CT review. Physica Medica 79 (2020) Pitch 0.4 not commercially available in all countries. 126–136. Their future availability cannot be guaranteed. Photon-counting CT case reports 49 Case report · Orthopedics Non-osseous subtalar coalition Adrian A. Marth, MD1,2; Daniel Nanz, PhD1; Reto Sutter, MD2 1 Swiss Center for Musculoskeletal Imaging, Balgrist Campus AG, Zurich, Switzerland 2 Balgrist University Hospital, University of Zurich, Zurich, Switzerland History Comments A 22-year-old female patient, Tarsal coalition is an abnormal, con- images play an essential role in complaining of persistent pain in genital bridging of two or more tarsal surgical planning. Despite the low the right foot for the past 3 months, bones. The bridging can be osseous radiation dose (1.3 mGy) applied presented herself to our orthopedic (bony bridging), or non-osseous to this young patient, high spatial clinic. The pain was localized at (fibrous / cartilaginous bridging). resolution and low image noise the medial side of the ankle and Treatment options range from con- are achieved. This is because UHR exacerbated during prolonged servative to surgical. A CT evaluation mode applies a fine collimation of standing. Clinical examination on the size, location, presence of 120 × 0.2 mm, without additional revealed a hindfoot valgus and degenerative changes, additional combs or grids to reduce the detector limited subtalar motion. Conventional coalitions and the degree of joint aperture, which improves the spatial radiographs showed a typical talar involvement is important for treat- resolution at full dose efficiency. beak sign, suggestive of tarsal ment planning. Additionally, electronic noise is elimi- coalition. The patient underwent a The first-line treatment is conserva- nated and a refined model based conservation treatment phase with iterative reconstruction (Quantum anti-inflammatory pain medications tive consisting of foot arch support, and responded well. She was then cast immobilization and non-steroidal Iterative Reconstruction, QIR) is anti-inflammatory medications. In applied in PCCT contributing to scheduled for surgery. CT was per- refractory cases, surgical treatment further image noise reduction. As formed to evaluate the size, location and extent of the coalition for pre- is performed, unless significant a result, the UHR images can even operative workup. An ultra-high degeneration in the adjacent joints be used in generating cinematic resolution (UHR) scan mode was contraindicates. Arthroscopic or open rendering 3D images which facilitate performed on a photon-counting CT resection can be performed with or communications between the (PCCT), NAEOTOM Alpha®. without the use of additional interpo- physicians and with the patient. sition materials, however, in multiple The combination of improved spatial coalitions, individual resections resolution with reduced image noise Diagnosis should not be pursued, as they is highly beneficial for musculoskele- are unlikely to establish a normal tal imaging in clinical routine. UHR CT images showed an irregular and narrowed subtalar joint, involving functional outcome. Arthrodesis both the middle and posterior sub- is preferred if more than 50% of the talar facet, with more than 50% of joint surface area are involved and the surface area. There was no a higher degree of hindfoot valgus evidence of adjacent osteoarthritis. is present. Triple arthrodesis, instead An osseous outgrowth at the mid of subtalar arthrodesis, is indicated The statements by customers of Siemens portion of the superior margin of when the midfoot joints show signs Healthineers described herein are based on results that were achieved in the customer’s the talus ("talar beak") was seen as of osteoarthritis in subtalar coalitions. unique setting. Because there is no “typical” a typical secondary sign of tarsal In this case, since more than 50% of hospital and many variables exist (e.g., hospital coalition. No osseous bridging of the surface area of the subtalar joint size, case mix, level of IT and/or automation adoption) there can be no guarantee that the subtalar joint was present. A is involved, and there is no evidence other customers will achieve the same results. diagnosis of non-osseous coalition of adjacent osteoarthritis, a subtalar was confirmed. The patient was arthrodesis is indicated. CT findings The products/features (mentioned herein) are not commercially available in all countries. scheduled for a subtalar arthrodesis. that are clearly depicted in UHR Their future availability cannot be guaranteed. 50 Photon-counting CT case reports Orthopedics · Case report 1a 1b 1c 1 MPR images (Fig. 1a–1c) and cVRT images (Fig. 1d–1e) of PCCT examination of the right foot show an irregular and narrowed subtalar joint involving both middle and posterior subtalar facet, which are deformed (arrows). There are no signs of bony bridging, confirming the diagnosis of a non-osseous talocalcaneal coalition. Additionally, a talar beak can be seen at the superior aspect of the talus head (arrowhead). Note that the input images for cVRT creation are reconstructed at 0.2 mm, with a very sharp kernel of Br84 and an image matrix of 1024 × 1024. Examination Protocol 1d Scanner NAEOTOM Alpha Scan area Right ankle Scan mode UHR mode (Quantum HD) Scan length 118.3 mm Scan direction Cranio-caudal Scan time 2.9 s Tube voltage 120 kV Effective mAs 16 mAs Dose modulation CARE Dose4D 1e CTDIvol 1.3 mGy DLP 17.6 mGy*cm Rotation time 0.5 s Pitch 0.85 Slice collimation 120 x 0.2 mm Slice width 0.2 mm Reconstruction increment 0.1 mm Reconstruction kernel Br84 Reconstruction matrix 1024 x 1024 Photon-counting CT case reports 51 Case report · Orthopedics Pseudarthrosis revision of a comminuted tibia fracture – consolidated? Adrian A. Marth, MD1,2; Daniel Nanz, PhD1; Reto Sutter, MD2 1 Swiss Center for Musculoskeletal Imaging, Balgrist Campus AG, Zurich, Switzerland 2 Balgrist University Hospital, Zurich, Switzerland History healing process. This information References is pivotal for surgeons to decide [1] Adrian A. Marth, et al. Photon-Counting A 46-year-old male patient, present- about patient mobility, or whether Detector CT – Clinical Utility of Virtual ing with a comminuted tibia fracture, revision surgery is necessary in case Monoenergetic Imaging Combined With underwent pseudarthrosis revision of complications such as delayed Tin Prefiltration to Reduce Metal Artifacts with plate osteosynthesis and locking union or non-union. Metal artifacts in the Postoperative Ankle. Invest Radiol. 2024 Jan 10. DOI:10.1097/ screws. Six weeks later, a follow- caused by implants, due to photon RLI.0000000000001058 up CT examination was scheduled starvation and beam hardening, can to evaluate the status of osseous significantly compromise image inter- healing. A scan in ultra-high reso- pretability. It has been shown that a lution (UHR) mode with spectral Examination Protocol combined approach, using spectral shaping (tin filtration) was per- shaping (tin filtration) and virtual Scanner formed on a photon-counting CT monoenergetic image (VMI) recon- NAEOTOM Alpha (PCCT), NAEOTOM Alpha®. structions, is effective in reducing Scan area Left lower metal artifacts at improved dose extremity Diagnosis efficiency compared to standard scans [1]. While spectral shaping Scan mode UHR mode (Quantum HD) In the standard polychromatic UHR excludes low-energy photons that images, metal artifacts caused by the contribute little to high contrast Scan length 428.5 mm implants were present and partially structures (i.e., bone, metal), VMIs obscured the visualization of the further shift the mean photon energy Scan direction Caudo-cranial fracture clefts. Virtual monoenergetic to higher levels, thereby reducing Scan time 3.5 s images (VMI), reconstructed at beam hardening artifacts. VMIs Tube voltage Sn140 kV 120 keV, 150 keV and 190 keV, can be easily reconstructed and showed substantial suppression implemented in routine imaging as Effective mAs 97 mAs of metal artifacts and improved spectral information is inherently available in PCCT. Furthermore, PCCT Dose modulation CARE Dose4D visibility of the fracture clefts. No sign of osseous consolidation can acquire UHR images without was evident. Spotty osteopenia was using additional combs or grids to CTDIvol 3.5 mGy present in the tibia and the foot. reduce the detector aperture, result- DLP 150 mGy*cm ing in an increased spatial resolution Following the CT scan, the patient at full dose efficiency. Rotation time 0.5 s was instructed to walk using forearm In this particular case, metal arti- Pitch 0.86 crutches and applying only 30% of his own body weight onto his feet. facts are better suppressed in VMIs Slice collimation 120 × 0.2 mm The patient was scheduled to return reconstructed at higher keV levels (150 and 190 keV). However, a trade- Slice width 0.2 / 0.4 mm 6 weeks later for the next follow-up examination. off with reduced image contrast has Reconstruction 0.1 / 0.4 mm to be recognized. Clear visualization increment of the fracture clefts is observed Comments in VMIs reconstructed at 120 keV, Reconstruction Br84 / Br76 while image contrast is still satis- kernel QIR 3 CT assessment following surgery factory. The improved visibility can is important to identify whether a increase diagnostic confidence for Spectral VMI (Mono- fracture consolidates during the providing better patient care. reconstruction energetic Plus) 52 Photon-counting CT case reports Orthopedics · Case report 1a 1b 1 Sagittal MPR images show a fracture cleft (arrows) that is partially obscured by metal artifacts on the polychromatic image (Fig. 1a), and is however clearly visible on VMI images reconstructed at 120 keV (Fig, 1b), 150 keV (Fig. 1c) and 190 keV (Fig. 1d). No sign of osseous consolidation is evident. 1c 1d 2a 2b 2c 2d 2 Cinematic volume rendered images (a–d) show a 3D overview of the plate osteosynthesis and locking screws in relation to the fractured tibia and fibula. The statements by customers of Siemens Healthineers described herein are based on results that were achieved in the customer’s unique setting. Because there is no “typical” hospital and many variables exist (e.g., hospital size, case mix, level of IT and/or automation adoption) there can be no guarantee that other customers will achieve the same results. The products/features (mentioned herein) are not commercially available in all countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 53 Case report · Pediatrics Pediatric ureterocele complicated by urolithiasis Jan Baxa, MD, Ph.D. Department of Imaging Methods, University Hospital Pilsen and Medical Faculty of Charles University, Pilsen, Czech Republic History A 9-year-old boy, suffering from weddellite and whewellite. A follow- a CTDI value as low as 0.77 mGy is frequent urination, weak stream up session of cystourethroscopy was achieved for the entire abdominal and enuresis, was presented to scheduled to extract the residual and pelvic scan. Less image the hospital for a check-up. Ultra- stones in the kidney. noise also contributes to a three- sonography and cystoradiography dimensional demonstration of revealed hydronephrosis and anatomical details. Slices, as thin hydroureter on the right side, Comments as 0.4 mm, can be used to create accompanied by multiple stones An ureterocele is a congenital lifelike images using cinematic in the distal ureter. An abdominal abnormal dilation of the distal-most volume rendering technique (cVRT), contrast CT examination was portion of the ureter, protruding into assisting the surgeons in planning an requested for further evaluation, prior to the cystourethroscopy the bladder. It can be asymptomatic appropriate procedure. Note that the and is often diagnosed later in life contrast agent is administered using procedure. due to urolithiasis or is incidentally a two-bolus protocol – 30 mL in the found through diagnostic imaging first bolus and 25 mL in the second, Diagnosis performed for other reasons than a both with a 25 mL saline chaser. suspicious ureterocele. Ureteroceles After the first contrast bolus, there CT images showed a markedly dilated complicated by urolithiasis are not is a waiting period of 1.5 hours to right renal pelvis and calyces as well secure a well-filled dilated excretory as the right ureter, indicating hydro- uncommon. Ultrasonography is system. A start delay of 40 seconds nephrosis and hydroureter. Multiple primarily used for imaging diagnosis in pediatric patients. CT or MRI is applied after the second bolus for smooth round stones, measuring are valuable to further define the better vascular and parenchymal 4 – 5 mm in diameter, were seen in ureterocele anatomy in complex enhancement. Using this approach, the distal segment of a single dilated only one scan, instead of two, is right ureter, which protruded into cases to guide surgical procedures. necessary, further reducing the the bladder lumen. The right ureteral This case is performed on a dual radiation exposure to the pediatric orifice was not visible. A single stone, source photon-counting CT (PCCT), patient. As shown in this case, located inferiorly in the dilated renal NAEOTOM Alpha®. It provides with the advanced PCCT Quantum calyx and posteriorly in the protruded energy-resolved CT data without technology, optimal image quality ureterocele, was also seen. The left electronic noise, which is eliminated with reduced radiation dose can renal system was unremarkable. by setting up a predefined digital be achieved for pediatric scans in CT findings suggested an ureterocele threshold for counting X-ray photons clinical routine. with urolithiasis. far above the electronic noise floor. Subsequently, the patient underwent [2] In the image reconstruction References a successful ureterocele resection, process, a model based iterative stones extraction and stent imple- reconstruction approach – Quantum [1] Xie et al. Ureterocele: Review of Presentations, Types and Coexisting mentation between the renal pelvis Iterative Reconstruction (QIR) – Diseases. Int Arch Urol Complic 2017, is applied for further image noise 3:024. DOI: 10.23937/ and the bladder via cystoscopy. reduction. These improvements 2469-5742/1510024. 25 stone pieces were extracted and the laboratory analysis revealed contribute to the reduction of image noise as well as radiation dose. By [2] Thomas Flohr, et al. Photon-counting calcium-oxalate stones with 50/50 CT review. Physica Medica 79 (2020) using an optimized 70 kV protocol, 126–136. 54 Photon-counting CT case reports Pediatrics · Case report Examination Protocol 1a HPR 1b Scanner NAEOTOM Alpha Scan area Abdomen/Pelvis Scan mode Quantum Scan length 271.4 mm Scan direction Cranio-caudal Scan time 1.6 s Tube voltage 70 kV * Effective mAs 67 mAs Dose CARE Dose4D modulation 2a 2b CTDIvol 0.77 mGy DLP 24.9 mGy*cm Rotation time 0.5 s Pitch 1.5 Slice 144 x 0.4 mm collimation 3a H 3b Slice width 0.4 mm Reconstruction 0.2 mm increment Reconstruction Br36, QIR 3 kernel Spectral Monoenergetic Plus reconstruction Contrast 350 mg/mL Volume 1st bolus (30 mL + 25 mL saline) 1.5 hrs pause – – 2nd bolus (25 mL + 20 mL saline) Flow rate 1.5 mL/s Start delay 40 s The statements by customers of Siemens 1 A thin MIP image (Fig. 1a) shows a markedly dilated right renal pelvis and calyces Healthineers described herein are based on as well as the right ureter. The distal-most portion of the ureter, protruding into the results that were achieved in the customer’s bladder lumen, is also seen (asterisk). A cVRT image (Fig. 1b) shows the locations unique setting. Because there is no “typical” hospital and many variables exist (e.g., hospital of multiple stones (arrows). size, case mix, level of IT and/or automation adoption) there can be no guarantee that 2 An axial image (Fig. 2a) and a cVRT 3 A sagittal MPR image (Fig. 3a) and other customers will achieve the same results. image (Fig. 2b) show the ureterocele a cVRT image (Fig. 3b) show the The products/features (mentioned herein) are protruding into the bladder (arrows) ureterocele protruding into the not commercially available in all countries. and multiple stones in the dilated bladder (arrows) and multiple stones Their future availability cannot be guaranteed. distal ureter (dotted arrow). in the dilated distal ureter. Photon-counting CT case reports 55 Case report · Vascular Macromastia with severe ptosis Chao Zhang, RT1; Daming Zhang, MD1; Man Wang, RT1; Jin Chen, RN1; Xi Zhao, MD2; Yun Wang, RT1 1 Department of Radiology, Peking Union Medical College, Beijing, P. R. China 2 Siemens Healthineers, China History A 32-year-old female patient, suffer- The patient underwent a successful individualized design of the reduc- ing from bilateral symptomatic breast reduction mammaplasty and pedi- tion mammaplasty. hypertrophy with severe ptosis cled nipple-areola reconstruction (grade 3) after breastfeeding within with a satisfactory outcome. This case was performed with a dual- the past eight years, was scheduled source PCD-CT, NAEOTOM Alpha, for a reduction mammoplasty. Prior which provides energy-resolved CT to surgery, a CT angiography (CTA) Comments data at improved spatial resolution was performed, using an ultra-high with inherent spectral information, resolution (UHR) scan mode with a Macromastia, aka breast hypertro- without electronic noise. [4] These dual-source photon-counting detec- phy, is a medical condition character- advanced techniques contribute to tor (PCD) CT, NAEOTOM Alpha®, to ized by an excessive growth of breast the improvement of imaging the assess the dominant blood supply size, imposing physical and psycho- details of the small terminal arteries of the nipple-areola complex (NAC) logical challenges to the patients. to the NAC. The individual detector and its vascular sources. There is no lasting non-operative pixels of the PCD are defined by a treatment for symptomatic breast strong electric field, instead of physi- hypertrophy and its precise etiology cal separation applied with the con- Diagnosis remains elusive. [1] Surgical treat- ventional energy-integrating detector ment by reduction mammaplasty has (EID) CT, resulting in small subpixels CTA images revealed a symmetrical been recognized in the guidelines without loss of radiation dose pattern of a single source artery on as the best approach to symptomatic efficiency. The UHR mode therefore both sides. The dominant arteries relief and constitutes the most com- features a fine collimation of 120 x branched off the internal thoracic mon therapy. [2] However, postoper- 0.2 mm and very high in-plane arteries at the first intercostal space ative functional loss or even necrosis resolution. In addition, spectral infor- on the right and at the second inter- of the NAC, resulting from injuries mation is available at a slice width costal space on the left, supplying of the arteries during the operation, of 0.4 mm, to display VMIs at a lower blood to the NAC region. Virtual may occur due to the complexity of keV level (50 keV in this case), thus monoenergetic images (VMI) dis- the blood supply. An incidence rate improving contrast enhancement. played at 50 keV showed increased of up to 13% has been reported. [3] The absence of the electronic noise contrast enhancement and improved Studies have shown that the blood prompts a potential dose reduction visualization of the terminal arteries supply pattern of the NAC is highly (4.5 mGy in this case) while retaining for the NAC. These images were used variable among individuals and even optimal image quality. to create three dimensional (3D) im- between the right and left breast of ages with cinematic volume render- the same person. The source artery As shown in this case, pre-operative ing technique (cVRT). Different pre- can be single or multiple, with a CTA imaging facilitates a comprehen- sets were applied to demonstrate the symmetrical or asymmetrical pattern. sive understanding of the primary anatomical relationship between the In some cases, the dominant artery blood supply in the NAC region, and arteries and the bones, as well as may not be visualized, when the is thus a useful tool in the assistance the muscles and the fatty tissues, detectable diameter threshold is of surgical planning for reduction matching the surgical position of the set to beyond 1.0 mm. [3] It is mammaplasty. The UHR images patient. The rendering results were therefore important to have CTA acquired with PCD-CT demonstrate projected for holographic localization images with a high resolution for the potential of improving the and the arteries were pre-operatively a better understanding of the NAC vascular details at a reduced radia- marked on the patient’s body. blood supply to achieve a successful, tion dose. 56 Photon-counting CT case reports Vascular · Case report 1a 1 cVRT images show a symmetrical pattern of a single source artery on both sides. The dominant arteries branch off the internal thoracic arteries at the first intercostal space on the right and at the second intercostal space on the left, supplying blood to the NAC region. The anatomical relation- ship between the arteries and the bones (Fig. 1a), the muscles (Fig. 1b), and the fatty tissues (Fig.1c), is demonstrated using different presets, and matching surgical position of the patient. Examination Protocol 1b Scanner NAEOTOM Alpha Scan area Thorax Scan mode UHR mode (Quantum HD) Scan length 264.8 mm Scan direction Cranio-caudal Scan time 3.9 s Tube voltage 120 kV 1c Effective mAs 56 mAs IQ level 102 Dose modulation CARE Dose4D CTDIvol 4.5 mGy DLP 123 mGy*cm Rotation time 0.25 s Pitch 0.7 Slice collimation 120 x 0.2 mm Slice width 0.2 / 0.4 mm Reconstruction increment 0.2 / 0.2 mm Reconstruction kernel Bv60 References Spectral reconstruction Monoenergetic Plus [1] X. Li, et al. Preoperative visualization of mammary artery for breast reduction surgery based on Contrast computed tomography angiography. Egypt J Radiol 370 mg/mL Nucl Med (2024) 55:1. https://doi.org/10.1186/ Volume 50 mL + 40 mL (80%) + 20 mL saline s43055-023-01170-2. Flow rate 5 mL/s + 4.5 mL/s + 4 mL/s [2] American Society of Plastic Surgeons. Evidence-based Clinical Practice Guideline: Reduction Mammaplasty. Start delay 40 s www.plasticsurgery.org. [3] H. Zheng, et al. Computed Tomographic Angiography- Based Characterization of Source Blood Vessels for The statements by customers of Siemens Healthineers described herein are based Nipple–Areola Complex Perfusion in Hypertrophic on results that were achieved in the customer’s unique setting. Because there is no Breasts. Aesth Plast Surg (2017) 41:524–530. DOI “typical” hospital and many variables exist (e.g., hospital size, case mix, level of IT and/or automation adoption) there can be no guarantee that other customers will 10.1007/s00266-017-0791-5. achieve the same results. [4] Thomas Flohr, et al. Photon-counting CT review. The products/features (mentioned herein) are not commercially available in all Physica Medica 79 (2020) 126–136. countries. Their future availability cannot be guaranteed. Photon-counting CT case reports 57 Explore the power of photon-counting CT CT data provided by Erasmus MC, Rotterdam, The Netherlands The picture is an artistic rendering of images acquired on photon-counting CT, and cannot be directly rendered by the CT scanner or its software. 58 59 Siemens Healthineers Headquarters Siemens Healthineers AG Siemensstr. 3 91301 Forchheim, Germany Phone: +49 9191 18-0 siemens-healthineers.com Published by Siemens Healthineers AG · Order No. CT-00112-11C1-7600 · Printed in Germany · 15639 1024 · ©Siemens Healthineers AG, 2024