First in-human quantitative plaque characterization with ultra-high resolution coronary photon-counting CT angiography

Abstract

PurposeTo assess the effect of ultra-high-resolution coronary CT angiography (CCTA) with photon-counting detector (PCD) CT on quantitative coronary plaque characterization.Materials and methodsIn this IRB-approved study, 22 plaques of 20 patients (7 women; mean age 77 ± 8 years, mean body mass index 26.1 ± 3.6 kg/m2) undergoing electrocardiography (ECG)-gated ultra-high-resolution CCTA with PCD-CT were included. Images were reconstructed with a smooth (Bv40) and a sharp (Bv64) vascular kernel, with quantum iterative reconstruction (strength level 4), and using a slice thickness of 0.6, 0.4, and 0.2 mm, respectively (field-of-view 200 mm × 200 mm, matrix size 512 × 512 pixels). Reconstructions with the Bv40 kernel and slice thickness of 0.6 mm served as the reference standard. After identification of a plaque in coronary arteries with a vessel diameter ≥2 mm, plaque composition was determined using a dedicated, semi-automated plaque quantification software. Total plaque, calcified, fibrotic, and lipid-rich plaque components were quantified in all datasets.ResultsMedian plaque volume was highest (23.5 mm3, interquartiles 17.9–34.3 mm3) for reconstructions with the reference standard and lowest for ultra-high-resolution reconstructions with a slice thickness of 0.2 mm and the Bv64 kernel (18.1 mm3, interquartiles 14.1–25.8 mm3, p < 0.001). Reconstructions with the reference standard showed largest calcified (85.1%, interquartiles 76.4–91.1%) and smallest lipid-rich plaque components (0.5%, interquartiles 0.0–1.5%). Smallest calcified plaque components (75.2%, interquartiles 69.9–80.8%) and largest lipid-rich components (6.7%, interquartiles 5.1–8.4%) were found for ultra-high-resolution reconstructions with a slice thickness of 0.2 mm and the Bv64 kernel. At an identical slice thickness, volume of calcified components was always lower, and volume of lipid-rich components was always higher for reconstructions with the Bv64 kernel compared with reconstructions with the Bv40 kernel (all, p < 0.001).ConclusionThis patient study indicates significant differences of ultra-high-resolution scanning with PCD-CT on quantitative coronary plaque characterization. Reduced blooming artifacts may allow improved visualization of fibrotic and lipid-rich plaque components with the ultra-high-resolution mode of PCD-CT.

Photon-counting detector CT: early clinical experience review

“…The latter study even demonstrated 40% less noise for PCD-CT UHR-based temporal bone imaging as compared to comb-filter UHR EID-CT imaging at matching radiation doses and reconstruction settings. 33 A variety of further studies have been published on HR and UHR PCD-CT imaging highlighting its value for lung assessment, 15,25,27,[34][35][36][37][38][39] cardiac imaging 20,24,[40][41][42][43][44] and musculoskeletal applications. 19,33,[45][46][47][48] UHR imaging is of particular interest for these anatomical areas because the clear depiction of fine details may effectively enhance diagnostic accuracy.…”

“…24,40 Two recent studies assessing the UHR scan mode of clinical PCD-CT in patients referred for coronary CT angiography have shown that coronary arteries can be visualized in excellent quality with improved visualization of non-calcified plaque components and with reduced blooming of calcified plaques. 43,44 For bone imaging, fine bone details and previously occult hairline fractures may become apparent. 33,46,49,50 In a clinical feasibility study including 32 patients who underwent both UHR PCD-CT imaging on a prototype CT system with optimized reconstruction settings and standard-of-care EID-CT imaging, Baffour et al reported improved visualization of osseous structures of the pelvis and shoulder for UHR PCD-CT imaging at a 31-47% lower radiation dose.…”

New Horizons in Vascular Imaging With Photon-Counting Detector CT

“…In general, diagnostic confidence will increase with PCD-CT compared with EID-CT in terms of coronary calcifications, calcification sharpness, and calcification conspicuity, but also noncalcified plaque conspicuity. 5,26 However, a systematic evaluation of the PureLumen technique against an invasive reference standard (ie, catheter angiography) is still missing and must be subject of future studies.…”

Advanced Neuroimaging With Photon-Counting Detector CT

“…Photon-counting detector CT enables higher spatial resolution in comparison with conventional EIDs. Photon-counting detector CT scanners can be manufactured with smaller detector elements that do not contain separate scintillator elements and reflecting septa, generating pixel sizes ranging from 0.225 to 0.5 mm at the detector, contrasting pixel sizes in the order of 1 mm created by EIDs 40–42 . The advances in spatial resolution may be translated to clinical applications for visualization of very fine anatomic superstructures that extend beyond the current resolution capacities of state-of-the-art EIDs.…”