Protocols

In 51 patients with 51 coronary plaques, PCCT VMI energy had a substantial effect on measured plaque attenuation and consequently on quantitative plaque composition when fixed HU thresholds were used. Mean plaque attenuation fell progressively from 723 ± 501 HU at 40 keV to 120 ± 112 HU at 180 keV, while 70-keV VMI most…

PCCT-derived virtual unenhanced (VUE) images showed no significant difference in mean attenuation compared with true unenhanced (TUE) images for adrenal adenomas (9.2 ± 8.6 HU vs 7.3 ± 8.4 HU; P = .07). Despite similar mean values, individual VUE measurements showed both over- and underestimation, resulting in 10 of 36…

In 18 patients with 44 coronary stents, ultra-high-resolution (UHR) PCCT angiography achieved high diagnostic accuracy for detecting ≥50% in-stent stenosis compared with invasive coronary angiography (ICA). Both readers identified all 5 stenotic stents, yielding 100% sensitivity. Specificity and overall accuracy were 92.3%…

In 170 patients, coronary artery calcium scores derived from PCCT PureCalcium virtual noncontrast images showed excellent correlation with true noncontrast (TNC) calcium scoring (ICC 0.98). Median Agatston scores were not significantly different: 4.8 vs 2.7, respectively (p = 0.99). High correlation did not translate into…

In 27 patients undergoing same-day PCCT and cardiac MRI, myocardial extracellular volume (ECV) measurements remained robust across a wide range of reconstruction settings, but reconstruction choices meaningfully affected agreement with MRI. The greatest improvement came from combining thin slices with low-keV VMI, rather…

Standard PCCT virtual noncontrast (VNC) calcium scoring performs well for larger and denser plaques but can miss subtle disease. Large/medium and high/medium-density plaques showed strong agreement with true noncontrast (TNC) scoring (r > 0.9; ICC ≥ 0.90), whereas low-density plaques showed poor agreement and small plaques…

In 39 patients with 45 lower-extremity run-off studies, PCCT angiography was compared directly with digital subtraction angiography (DSA) for peripheral arterial occlusive disease. The cohort was challenging, with 77.8% of studies representing Fontaine stage IV disease, making severe calcification and small crural vessels…

In this prospective same-day comparison of 29 patients, myocardial extracellular volume (ECV) measured with PCCT showed strong agreement with cardiac MRI, supporting spectral PCCT as a quantitative tool for myocardial tissue characterization. Dual-energy PCCT achieved correlations of r = 0.91 for global ECV and r = 0.82…

This prospective study compared 0.2-mm ultra-high-resolution (UHR) PCCT with 1-mm standard-resolution 40-keV VMI for abdominal CTA in 94 participants, equally divided between full-dose and low-dose protocols. Standard-resolution 40-keV VMI provided significantly higher SNR and CNR than all UHR reconstructions. UHR…

Prospective study testing whether low-dose (LD) ultra-high-resolution (UHR) photon-counting CT can preserve diagnostic image quality for visceral artery CTA. The study included 57 patients in the full-dose group and 57 in the low-dose group. Each acquisition was reconstructed two ways: 0.2 mm / Bv48 / QIR 4 and 1 mm / Bv40…

In 58 infants <10 kg, cardiac PCCT at 70 kV and 120 kV provided comparable image quality, with similar aortic CNR and median subjective image-quality scores of 5/5 in both groups. 70 kV reduced radiation dose by almost 50%, with CTDI decreasing from 0.25 mGy at 120 kV to 0.13 mGy at 70 kV (P<0.001). The key trade-off is…

This multicenter retrospective study evaluated 6,464 PCCT examinations in 4,772 pediatric patients across three French institutions and provides practical acquisition/reconstruction protocols across ten body regions. The cohort had a mean age of 7.9 ± 5.5 years (4 days–17.9 years); nearly one-third of examinations involved…

Combining UHR PCCT with low-keV virtual monoenergetic imaging (VMI) improved visualization of pancreatic ductal adenocarcinoma (PDAC), peripancreatic vessels, and fine pancreatic anatomy; the study identified 0.4-mm slices at 45 keV as the best overall reconstruction strategy for preoperative assessment. 40-keV VMI…

Virtual noncontrast (VNC) images reconstructed from contrast-enhanced PCCT provided accurate abdominal attenuation values compared with true noncontrast (TNC) imaging, supporting the potential to omit a separate TNC acquisition. Across all measurements, VNC attenuation errors were <5 HU in 76% and <10 HU in 95%; there was…

This case report has been published in Radiology. Access publication Figure 1. Axial photon-counting CT images at (A) 0.4-mm, (C) 2-mm, and (D) 4-mm section thickness demonstrate an incidental hypoattenuating pancreatic lesion (arrowhead). The lesion communicates with the main pancreatic duct via a connection (arrow)…

Retrospective single-center study of 507 patients undergoing unenhanced abdominal CT for suspected urinary calculi, comparing PCCT (n = 229) with optimized EID-CT (n = 278). PCCT achieved a 44% lower effective radiation dose than EID-CT: 0.79 mSv vs 1.39 mSv, while maintaining excellent diagnostic confidence. Despite the…

This proof-of-concept study is described as the first clinical PCCT study to characterize high-risk human carotid plaque features in living patients, using histology from subsequent carotid endarterectomy as the reference. The cohort comprised 10 symptomatic patients. Spectral PCCT could differentiate multiple plaque…

Automated Lung Texture Analysis (LTA) performed robustly on low-dose PCCT despite the algorithm having been trained on conventional EID-CT data. For detecting ILD, LTA achieved a higher AUC with PCCT than with EID-CT (0.846 vs. 0.772). PCCT showed consistently higher AUCs for individual ILD features, particularly…

PCCT-derived virtual non-contrast (VNC) images provided renal cyst attenuation measurements comparable to true non-contrast imaging, with no significant difference across true non-contrast, arterial VNC, and portal-venous VNC (p = 0.301). In contrast, dual-energy EID-CT VNC showed a significant difference from true…

PCCT-derived fat fraction (CTFF) showed excellent agreement with MRI proton density fat fraction (PDFF), supporting quantitative liver fat assessment using standardized PCCT attenuation values. A single conversion formula—MRI PDFF (%) = −0.58 × CT (HU) + 43.1—remained accurate across 90, 120, and 140 kVp and both standard-…

A streamlined PCCT myelography protocol enabled whole-spine evaluation at 0.2 × 0.1 mm resolution while limiting scanner time to approximately 15 minutes, making high-resolution CSF leak imaging feasible in a busy clinical setting. In 35 patients with previously inconclusive spine imaging, PCCT definitively identified a…

This retrospective study of 40 patients evaluated whether virtual monoenergetic images (VMI) reconstructed from portal venous PCCT could provide sufficient arterial vessel contrast and potentially serve as an alternative when a dedicated arterial phase is unavailable or suboptimal. 40-keV VMI produced the highest arterial…

PCCT virtual non-contrast (VNC) reconstructions differentiated adrenal adenomas from metastases on portal-venous contrast-enhanced imaging, with adenomas showing significantly lower attenuation on both conventional VNC (VNCConv) and calcium-preserving PureCalcium VNC (VNCPC) (p = 0.007). VNC nevertheless systematically…

PCCT virtual monoenergetic imaging (VMI) improved visualization of hypovascularized liver metastases, with the greatest lesion conspicuity and CNR achieved at the low end of the keV spectrum. At 40 keV, tumor-to-liver ratio (TLR) reached 0.37, while CNR peaked at 6.88. Compared with conventional EID-CT, PCCT showed lower…

This pilot study demonstrates that spectral information from photon-counting detector CT (PCD-CT) can help differentiate hyperdense renal cysts from vascular renal lesions when conventional portal-venous images are indeterminate. In 26 patients with 42 hyperdense renal lesions, attenuation on standard 70-keV VMI…

Cardiac PCCT integrated directly into the acute stroke CT workflow achieved 96% diagnostic accuracy, 90% sensitivity, 97% specificity, and a particularly strong 99% negative predictive value for left atrial appendage (LAA) thrombus compared with TEE. The cardiac acquisition was added immediately after stroke CTA with only…

Photon-counting detector (PCD) coronary CT showed less calcium blooming than conventional energy-integrating detector (EID) CT, resulting in systematically lower visual estimates of coronary luminal stenosis. In 25 patients scanned with both systems on the same day, median visual stenosis decreased from 31.8% to 20.6% for…

This phantom study demonstrates that ultra-high-resolution (UHR) photon-counting CT (PCCT) substantially improves visualization of low-attenuation plaque (LAP) compared with standard-resolution PCCT and a clinically used energy-integrating detector CT (EID-CT) protocol. The combination of UHR acquisition (120 × 0.2 mm…