Quantification of bone microarchitecture using photon-counting CT at different radiation doses: A comparison with µCT

BACKGROUND. Photon-counting detector (PCD) CT may allow lower radiation doses than used for conventional energy-integrating detector (EID) CT, with preserved image quality. OBJECTIVE. The purpose of this study was to compare PCD CT and EID CT, reconstructed with and without a denoising tool, in terms of image quality of the osseous pelvis in a phantom, with attention to low radiation doses. METHODS. A pelvic phantom comprising human bones in acrylic material mimicking soft tissue underwent PCD CT and EID CT at various tube potentials and radiation doses ranging from 0.05 to 5.00 mGy. Additional denoised reconstructions were generated using a commercial tool. Noise was measured in the acrylic material. Two readers performed independent qualitative assessments that entailed determining the denoised EID CT reconstruction with the lowest acceptable dose and then comparing this reference reconstruction with PCD CT reconstructions without and with denoising, using subjective Likert scales. RESULTS. Noise was lower for PCD CT than for EID CT. For instance, at 0.05 mGy and 100 kV with tin filter, noise was 38.4 HU for PCD CT versus 48.8 HU for EID CT. Denoising further reduced noise; for example, for PCD CT at 100 kV with tin filter at 0.25 mGy, noise was 19.9 HU without denoising versus 9.7 HU with denoising. For both readers, lowest acceptable dose for EID CT was 0.10 mGy (total score, 11 of 15 for both readers). Both readers somewhat agreed that PCD CT without denoising at 0.10 mGy (reflecting reference reconstruction dose) was relatively better than the reference reconstruction in terms of osseous structures, artifacts, and image quality. Both readers also somewhat agreed that denoised PCD CT reconstructions at 0.10 mGy and 0.05 mGy (reflecting matched and lower doses, respectively, with respect to reference reconstruction dose) were relatively better than the reference reconstruction for the image quality measures. CONCLUSION. PCD CT showed better-quality images than EID CT when performed at the lowest acceptable radiation dose for EID CT. PCD CT with denoising yielded better-quality images at a dose lower than lowest acceptable dose for EID CT. CLINICAL IMPACT. PCD CT with denoising could facilitate lower radiation doses for pelvic imaging.

To evaluate the patient-, vessel- and segment-based diagnostic performance of photon-counting detector CT (PCD-CT) compared to energy-integrating detector CT (EID-CT) for detecting ≥ 50% or ≥ 70% stenosis using invasive coronary angiography (ICA) as a reference standard. Patients with stable chest pain and ≥ 50% stenosis detected on dual source PCD-CT who subsequently underwent ICA were prospectively enroled. Diagnostic accuracy was calculated for PCD-CT vs ICA and additionally for a patient cohort scanned with EID-CT with similar risk profiles and disease prevalence. A Monte Carlo simulation based on diagnostic accuracy parameters was performed to estimate the potential reduction in ICA referrals. A total of 143 patients (66 ± 9 years, 27.3% female) with 572 vessels and 2431 segments were evaluated with PCD-CT and ICA. Regarding EID-CT, 109 patients (65 ± 9 years, 31.0% female), 436 vessels and 1853 segments were assessed, with every patient undergoing ICA. PCD-CT demonstrated significantly higher accuracy than EID-CT in detecting ≥ 50% stenosis: 88.1% vs 77.9% (patient level), 91.6% vs 77.8% (vessel level), and 97.7% vs 92.4% (segment level) (p < 0.01 for all). For detecting ≥ 70% stenosis, PCD-CT also showed higher accuracy than EID-CT: 90.9% vs 70.6% (patient level), 94.6% vs 80.9% (vessel level), and 98.6% vs 94.1% (segment level) (p < 0.01 for all). We demonstrated a potential mean reduction of 14.8% in ICA referrals when utilising PCD-CT compared to EID-CT. PCD-CT provides improved per-patient, per-vessel and per-segment diagnostic performance in detecting obstructive CAD in symptomatic patients when compared to patients scanned on EID-CT. PCD-CT may lead to a significant decrease in ICA utilisation. Question Accurate coronary CT angiography guides treatment, but its diagnostic accuracy is limited by various factors. Findings Photon counting detector (PCD)-CT improved diagnostic performance in detecting ≥ 50% or ≥ 70% stenosis, potentially reducing unnecessary ICA referrals by 14.8%. Clinical relevance PCD-CT improves diagnostic accuracy over EID-CT and may reduce unnecessary ICA.

Flow diverters are a crucial element in the treatment of intracranial aneurysms. However, the optimal non-invasive follow-up imaging modality, particularly for the detection of in-stent stenosis, remains uncertain. This study aims to compare the performance of photon-counting detector CT (PCD-CT) in ultra-high-resolution (UHR) mode with flat-panel CT (FP-CT) for the evaluation of intracranial flow diverters. A phantom model for intracranial vessels was used to evaluate 15 flow diverters of various sizes and designs. Imaging was performed using both PCD-CT and FP-CT. Qualitative assessment of the stent lumen was conducted by three experienced neuroradiologists using a 5-point Likert scale. Quantitative analysis included measurements of lumen area, contrast to noise ratio and signal to noise ratio. FP-CT provided a significantly larger assessable stent lumen than PCD-CT at all dose levels (p < 0.05), with no significant differences between PCD-CT dose levels (p = 0.999). Increasing PCD-CT dose did not improve lumen visualization. SNR and CNR increased with PCD-CT dose (p < 0.001), peaking at CTDI 20, but showed diminishing returns beyond CTDI 10. Flow diverter diameter correlated positively with SNR and CNR (p < 0.05). Subjective image quality improved with PCD-CT dose (p < 0.001) but showed no significant difference beyond 10 mGy (p > 0.05). FRED devices had the lowest ratings, independent of imaging modality (p = 0.80). Our study demonstrated that while FP-CT provided superior visualization of the flow diverter lumen in a head phantom vessel model, subjective assessability ratings were comparable between FP-CT and PCD-CT when evaluated by experienced readers. PCD-CT at a CTDIvol of 10 mGy offered the best balance between image quality and radiation dose, making it a viable alternative for post-interventional assessment of flow diverters.

ObjectivesTo evaluate the radiation exposure, quantitative, and qualitative image quality in pediatric cardiac CT by using photon-counting detector computed tomography (PCD CT) versus energy-integrating detector CT (EID CT) in matched children.Materials and methodsThirty-seven contrast-enhanced, clinically indicated cardiac CTs performed on PCD CT were matched with 37 examinations acquired by EID CT. The patients were matched according to water-equivalent diameters. Quantitative evaluation of image quality comprised a region of interest (ROI)-based analysis, calculating image noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratio. Differences of the attenuation variation of the paraspinal and the pectoral muscles were calculated to measure beam hardening artifacts. Volume CT dose index (CTDIvol) and dose length product (DLP) were documented, and the effective radiation dose was calculated for each patient. Statistical analysis comprised t-tests and Wilcoxon signed rank tests.ResultsThe mean age of the children on PCD CT was 794 ± 1016 days, similar to the mean age of 815 ± 957 days of the children on EID CT (p = 0.76). Moreover, age, height, weight, and body mass index (BMI) were also not significantly different between the two groups (p ≥ 0.32). Radiation exposure was significantly lower on PCD CT (CTDIvol 0.20 ± 0.12 mGy and DLP 4.06 ± 3.22 mGy*cm) versus EID CT (CTDIvol 0.37 ± 0.17 mGy, p < 0.001 and DLP 7.21 ± 4.67 mGy*cm, p < 0.001). No significant differences in SNR, CNR, or beam hardening artifacts could be observed. Qualitative image quality was also comparable for PCD CT versus EID CT.ConclusionsWith a reduction in radiation exposure exceeding 40% by using PCD CT, image quality remained stable compared to EID CT. Reducing radiation with PCD CT while preserving image quality might substantially advance cardiac imaging in children.Key PointsQuestionChildren are particularly sensitive to radiation exposure, highlighting the need for dose reduction.FindingsRadiation dosage can be significantly reduced while preserving image quality when using photon-counting detector (PCD) CT in pediatric patients with congenital heart disease.Clinical relevanceSince radiation exposure can be significantly reduced by PCD CT compared to energy-integrating detector (EID) CT, while image quality was comparable, PCD CT is advisable for children with congenital heart disease.Graphical

BackgroundReducing radiation and contrast media (CM) doses in computed tomography angiography (CTA) is especially relevant for potentially vulnerable populations. Low tube voltage photon-counting detector CT (PCD-CT) offers an improved iodine contrast-to-noise ratio (CNR) as compared to conventional CT scanners. We investigated optimized radiation and CM doses of PCD-CT angiography at low tube voltage in an animal model.MethodsSix minipigs (median weight: 32.5 kg; IQR: 29.8–34.6 kg) underwent thoracoabdominal CTA using a clinical dual-source PCD-CT at 70 kVp with three scan protocols: (A) reference (100% CM and radiation dose), (B) increased radiation (233%) and reduced CM (56%) dose, and (C) reduced radiation (50%) and increased CM (141%) dose. CNR, subjective image quality, and radiation doses were assessed, with statistical analysis including Mann–Whitney U-test and Kruskal–Wallis tests.ResultsCTDIvol was 1.7 mGy (IQR: 1.5–1.8) for scan A, 4.3 mGy (IQR: 3.8–4.7) for scan B, and 0.9 mGy (IQR: 0.8–1.0) for scan C (p < 0.001). CM volumes were 16 mL (IQR: 15–17) for scan A, 10 mL (IQR: 8–10) for scan B, and 23 mL (IQR: 21–24) for scan C. No significant differences in CNR were found between scans, with medians of 26 (IQR: 24–28) for scan A, 23 (IQR: 22–26) for scan B, and 26 (IQR: 24–30) for scan C (p = 0.276). Subjective image quality was similar across scans (p = 0.342).ConclusionLow tube voltage PCD-CT angiography allows substantial reductions in radiation and CM dose while maintaining stable and improved CNR, which allows further dose flexibility for individualized CTA protocols.Relevance statementPCD-CT at low tube voltage provides a high CNR and great flexibility in dose optimization, making it particularly effective for applications where minimizing radiation and CM exposure is a priority.Key PointsLow tube voltage imaging with photon counting detector (PCD)-CT enables flexible contrast and radiation dose optimization strategies in thoracoabdominal CT angiography (CTA).The CNR for thoracoabdominal CTA remains stable with appropriate contrast and radiation dose adjustments at low tube voltage PCD-CT.Low tube voltage PCD-CT consistently yields diagnostic image quality in thoracoabdominal angiography even at reduced contrast or radiation doses.Graphical

The introduction of photon-counting detector CT (PCD-CT) marks a remarkable leap in innovation in CT imaging. The new detector technology allows X-rays to be converted directly into an electrical signal without an intermediate step via a scintillation layer and allows the energy of individual photons to be measured. Initial data show high spatial resolution, complete elimination of electronic noise, and steady availability of spectral image data sets. In particular, the new technology shows promise with respect to the imaging of osseous structures. Recently, PCD-CT was implemented in the clinical routine. The aim of this review was to summarize recent studies and to show our first experiences with photon-counting detector technology in the field of musculoskeletal radiology.We performed a literature search using Medline and included a total of 90 articles and reviews that covered recent experimental and clinical experiences with the new technology.In this review, we focus on (1) spatial resolution and delineation of fine anatomic structures, (2) reduction of radiation dose, (3) electronic noise, (4) techniques for metal artifact reduction, and (5) possibilities of spectral imaging. This article provides insight into our first experiences with photon-counting detector technology and shows results and images from experimental and clinical studies. · This review summarizes recent experimental and clinical studies in the field of photon-counting detector CT and musculoskeletal radiology.. · The potential of photon-counting detector technology in the field of musculoskeletal radiology includes improved spatial resolution, reduction in radiation dose, metal artifact reduction, and spectral imaging.. · PCD-CT enables imaging at lower radiation doses while maintaining or even enhancing spatial resolution, crucial for reducing patient exposure, especially in repeated or prolonged imaging scenarios.. · It offers promising results in reducing metal artifacts commonly encountered in orthopedic or dental implants, enhancing the interpretability of adjacent structures in postoperative and follow-up imaging.. · With its ability to routinely acquire spectral data, PCD-CT scans allow for material classification, such as detecting urate crystals in suspected gout or visualizing bone marrow edema, potentially reducing reliance on MRI in certain cases.. Bette S, Risch F, Becker J et al. Photon-counting detector CT - first experiences in the field of musculoskeletal radiology. Fortschr Röntgenstr 2024; DOI 10.1055/a-2312-6914.

ObjectivesThis study aimed to evaluate the feasibility of low-tube-potential ultra-high-resolution (UHR) coronary CT angiography (CCTA) using photon-counting detector CT (PCD-CT) in comparison to low-tube-potential CCTA using energy-integrating detector CT (EID-CT), with a specific focus on the evaluation of coronary stents.Materials and methodsThis retrospective study included 54 patients (88 stents) who underwent CCTA in UHR mode on PCD-CT at low tube potential (PCDUHR-low; 27 patients [45 stents]) or CCTA with EID-CT at low tube potential (EID-low; 27 patients [43 stents]). The EID-low cohort was selected by propensity score matching to the PCDUHR-low cohort. Image quality of in-stent lumen was assessed using a 4-point Likert scale, with a score of 4 indicating “excellent.” Quantitative assessment of stents included stent-induced blooming, edge sharpness, stent full width at half maximum (FWHM) and ΔHUin-stent which quantifies the increase in CT attenuation within the stent lumen. Radiation dose was evaluated using CT dose index volume (CTDIvol) and dose–length product (DLP).ResultsPCDUHR-low had higher image quality scores than EID-low (scores of 3 and 4, 82.2% vs. 53.5%; p = 0.02). PCDUHR-low showed reduced stent-induced blooming, superior edge sharpness, smaller stent FWHM and smaller ΔHUin-stent than EID-low (all, p < 0.01). CTDIvol and DLP in PCDUHR-low (9.3 ± 4.4 mGy and 107.1 ± 50.4 mGy・cm) were comparable to those of EID-low (10.5 ± 5.9 mGy and 118.2 ± 74.9 mGy・cm), respectively. (p = 0.26 and 0.47).ConclusionCCTA using UHR mode in PCD-CT at low tube potential achieved superior image quality for implanted stent visualization as compared to EID-CT at low tube potential, while maintaining comparable radiation doses.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11604-025-01846-x.

Background Traditional energy-integrating detector CT has limited utility in accurately quantifying liver fat due to protocol-induced CT value shifts, but this limitation can be addressed by using photon-counting detector (PCD) CT, which allows for a standardized CT value. Purpose To develop and validate a universal CT to MRI fat conversion formula to enhance fat quantification accuracy across various PCD CT protocols relative to MRI proton density fat fraction (PDFF). Materials and Methods In this prospective study, the feasibility of fat quantification was evaluated in phantoms with various nominal fat fractions. Five hundred asymptomatic participants and 157 participants with suspected metabolic dysfunction-associated steatotic liver disease (MASLD) were enrolled between September 2023 and March 2024. Participants were randomly assigned to six groups with different CT protocols regarding tube voltage (90, 120, or 140 kVp) and radiation dose (standard or low). Of the participants in the 120-kVp standard-dose asymptomatic group, 51% (53 of 104) were designated as the training cohort, with the rest of the asymptomatic group serving as the validation cohort. A CT to MRI fat quantification formula was derived from the training cohort to estimate the CT-derived fat fraction (CTFF). CTFF agreement with PDFF and its error were evaluated in the asymptomatic validation cohort and subcohorts stratified by tube voltage, radiation dose, and body mass index, and in the MASLD cohort. The factors influencing CTFF error were further evaluated. Results In the phantoms, CTFF showed excellent agreement with nominal fat fraction (intraclass correlation coefficient, 0.98; mean bias, 0.2%). A total of 412 asymptomatic participants and 122 participants with MASLD were included. A CT to MRI fat conversion formula was derived as follows: MRI PDFF (%) = -0.58 · CT (HU) + 43.1. Across all comparisons, CTFF demonstrated excellent agreement with PDFF (mean bias values < 1%). CTFF error was not influenced by tube voltage, radiation dose, body mass index, or PDFF. Agreement between CTFF and PDFF was also found in the MASLD cohort (mean bias, -0.2%). Conclusion Standardized CT value from PCD CT showed a robust and remarkable agreement with MRI PDFF across various protocols and may serve as a precise alternative for liver fat quantification. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Wildman-Tobriner in this issue.

This study aims to compare the performance of first-generation dual-source photon-counting detector computed tomography (PCD-CT) to third-generation dual-source energy-integrating detector (EID-CT) regarding stent imaging in the femoral arterial runoff. Continuous extracorporeal perfusion was established in 1 human cadaver using an inguinal and infragenicular access and peristaltic pump. Seven peripheral stents were implanted into both superior femoral arteries by means of percutaneous angioplasty. Radiation dose-equivalent CT angiographies (high-/medium-/low-dose: 10/5/3 mGy) with constant tube voltage of 120 kVp, matching iterative reconstruction algorithm levels, and convolution kernels were used both with PCD-CT and EID-CT. In-stent lumen visibility, luminal and in-stent attenuation as well as contrast-to-noise ratio (CNR) were assessed via region of interest and diameter measurements. Results were compared using analyses of variance and regression analyses. Maximum in-stent lumen visibility achieved with PCD-CT was 94.48% ± 2.62%. The PCD-CT protocol with the lowest lumen visibility (BV40: 78.93% ± 4.67%) performed equal to the EID-CT protocol with the best lumen visibility (BV59: 79.49% ± 2.64%, P > 0.999). Photon-counting detector CT yielded superior CNR compared with EID-CT regardless of kernel and dose level ( P < 0.001). Maximum CNR was 48.8 ± 17.4 in PCD-CT versus 31.28 ± 5.7 in EID-CT (both BV40, high-dose). The theoretical dose reduction potential of PCD-CT over EID-CT was established at 88% (BV40), 83% (BV48/49), and 73% (BV59/60), respectively. In-stent attenuation was not significantly different from luminal attenuation outside stents in any protocol. With superior lumen visibility and CNR, PCD-CT allowed for noticeable dose reduction over EID-CT while maintaining image quality in a continuously perfused human cadaveric model.

Advancements in computed tomography (CT) technology, particularly the emergence of dual-energy CT (DE-CT) and photon-counting detector CT (PCD-CT), can improve detection, characterization, and treatment monitoring of focal liver lesions. DE-CT, through its ability to differentiate tissues with similar densities and produce diverse datasets, has enhanced lesion visibility and diagnostic precision. PCD-CT further advances imaging with superior spatial resolution and material decomposition capabilities, offering potential for complex diagnostic scenarios. This review aimed to highlight the role of CT in hepatic imaging and its application to focal liver lesions.DE-CT improves lesion detectability using low-energy virtual monochromatic images, which enhance iodine contrast and reduce radiation and contrast agent doses. It also facilitates treatment response evaluation after locoregional therapies for hepatocellular carcinoma by quantifying biomarkers, such as the extracellular volume fraction. This review underscores the transformative impact of DE-CT and PCD-CT on liver imaging, emphasizing their complementary roles alongside magnetic resonance imaging. These innovations have paved the way for more precise diagnostics, improved treatment planning, and enhanced patient outcomes in the management of liver diseases.

To develop a simple rule-of-thumb on how to reduce the contrast medium (CM) dose in photon-counting detector CT (PCD-CT) when lowering the energy of the reconstructed virtual mono-energetic images (VMI) while maintaining the contrast-to-noise ratio (CNR) for parenchymal CT and CTA. Spectral abdominal and chest CT phantoms were scanned using a portal venous phase (PVP) abdominal and a high-pitch CTA protocol, respectively, on a first-generation dual-source PCD-CT. The phantoms contained cylindrical rods with iodine in water equivalent material (0.5/1.0/2.0/5.0/10.0/15.0mg I/mL) and ICRU muscle tissue. The phantoms were complemented with 2 fat equivalent rings to mimic different patient sizes. Iodine contrast, image noise, noise power spectra (NPS), and iodine CNR were investigated in VMIs with different energies (40 to 60keV in steps of 5keV). This was done for different iodine concentrations, phantom sizes, x-ray tube voltages (120kV and 140kV) and radiation doses. In addition, 15 abdominal and 15 CT angiographic patient scans [body mass index (BMI) range: 17 to 37kg/m2] were retrospectively analyzed to determine the CNR at different VMI energies. Contrast at a given iodine concentration and VMI energy was independent of phantom size, radiation dose, and acquisition voltage (kV). With decreasing VMI energy, the maximum of the NPS curves increased, while their shape remained similar, indicating higher noise but similar noise texture. The CNR increased with lower VMI energy for a given iodine concentration and phantom size, while CNR decreased with increasing phantom size for a given VMI energy and iodine concentration. When the VMI energy was lowered by 5keV steps in the range of 60 to 40keV, similar CNR could be maintained when reducing the iodine concentration at each step by 11.7% to 13.7% for abdominal PVP scans and 11.8% to 14.5% for CTAs. CNR analysis of the patient scans confirmed these findings: a 5keV reduction in VMI energy led to a mean±SD 11.4%±0.4% and 13.7%±1.0% increase in CNR for abdomen PVP and CTA scans, respectively. This can be translated to a corresponding reduction in CM dose when a constant CNR is aimed for. From these results, a simple, robust rule-of-thumb was derived, the 10-to-5 rule: For the evaluated PCD-CT protocols, CNR can be maintained with about 10% less CM dose for each reduction of the VMI energy by 5keV. This phantom study, which was complemented with a retrospective proof-of-principle patient study, showed that a simple, easy to implement 10-to-5 rule-of-thumb might be used in daily practice for contrast-enhanced PCD-CT. It allows for individual adaptation of the CM dose to the VMI energy applied.

Image quality of photon counting and energy integrating chest CT – Prospective head-to-head comparison on same patients

To compare the diagnostic performance of photon-counting detector CT (PCD-CT) and energy-integrating detector CT (EID-CT) for colorectal polyp detection using a phantom model with histopathologically verified polyps. A phantom containing 84 histopathologically confirmed colorectal polyps from resected specimens underwent sequential PCD-CT and EID-CT scanning. Polyps were categorized by size as ≤ 5mm, 6-9mm, or ≥ 10mm. Two blinded abdominal radiologists evaluated image quality (5-point Likert scale), quantitative metrics (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]), detection sensitivity, and diagnostic confidence (3-point scale). Wilcoxon signed-rank and paired t-tests compared image quality parameters, McNemar's test compared detection rates, and inter-reader agreement was assessed using ICC and kappa statistics. PCD-CT demonstrated significantly superior qualitative image quality compared to EID-CT, with higher scores for overall quality (5 [4, 5] vs. 3 [3, 4]), sharpness (5 [4, 5] vs. 3 [1, 4]), and lower noise levels (5 [4, 5] vs. 3 [3, 3]) (all p < 0.001).Quantitative analysis showed superior SNR and CNR across all polyp sizes (all p < 0.001), with the most pronounced improvement in ≤ 5mm polyps (SNR: 143% increase, CNR: 149% increase). PCD-CT significantly improved detection rates for ≤ 5mm (71.4% vs. 17.9%, p < 0.001) and 6-9mm polyps (92.9% vs. 71.4%, p = 0.031). Reader confidence was also significantly higher with PCD-CT for ≤ 5mm (p < 0.001) and 6-9mm (p < 0.001) polyps, with substantial inter-reader agreement (kappa = 0.858; 95% CI:0.703-0.906). PCD-CT provides significantly improved diagnostic accuracy for colorectal polyp detection compared to EID-CT, with substantial gains in small polyp sensitivity and overall image quality.

CSF-venous fistulas are a common cause of spontaneous intracranial hypotension. Lateral decubitus digital subtraction myelography and CT myelography are the diagnostic imaging standards to identify these fistulas. Photon-counting CT myelography has technological advantages that might improve CSF-venous fistula detection, though no large studies have yet assessed its diagnostic performance. We sought to determine the diagnostic yield of photon-counting detector CT myelography for detection of CSF-venous fistulas in patients with spontaneous intracranial hypotension. We retrospectively searched our database for all decubitus photon-counting detector CT myelograms performed at our institution since the introduction of the technique in our practice. Per our institutional workflow, all patients had prior contrast-enhanced brain MR imaging and spine MR imaging showing no extradural CSF. Two neuroradiologists reviewed preprocedural brain MRIs, assessing previously described findings of intracranial hypotension (Bern score). Additionally, 2 different neuroradiologists assessed each myelogram for a definitive or equivocal CSF-venous fistula. The yield of photon-counting detector CT myelography was calculated and stratified by the Bern score using low-, intermediate-, and high-probability tiers. Fifty-seven consecutive photon-counting detector CT myelograms in 57 patients were included. A single CSF-venous fistula was definitively present in 38/57 patients. After we stratified by the Bern score, a definitive fistula was seen in 56.0%, 73.3%, and 76.5% of patients with low-, intermediate-, and high-probability brain MR imaging, respectively. Decubitus photon-counting detector CT myelography has an excellent diagnostic performance for the detection of CSF-venous fistulas. The yield for patients with intermediate- and high-probability Bern scores is at least as high as previously reported yields of decubitus digital subtraction myelography and CT myelography using energy-integrating detector scanners. The yield for patients with low-probability Bern scores appears to be greater compared with other modalities. Due to the retrospective nature of this study, future prospective work will be needed to compare the sensitivity of photon-counting detector CT myelography with other modalities.

Ultra-high-resolution photon-counting detector CT for visualization of the brachial plexus