(2026) Szilveszter | UHR PCCT improves detection of low-attenuation coronary plaque

Daniel Stromer

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 collimation), sharp Qr72 reconstruction kernels, and QIR 2–4 provided the highest spatial resolution and the most accurate attenuation values, allowing visualization of 1-mm LAP components that conventional EID-CT failed to resolve.

Higher virtual monoenergetic reconstructions (130 keV) reduced iodine blooming and improved differentiation between calcium, iodine, and lipid-rich plaque components, suggesting optimized PCCT protocols may improve future coronary plaque characterization.

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Figure 2. Low-attenuation plaque visualization on standard, UHR, and reference images using PCD-CT. Compared with the standard resolution (Qr40) and ultra-high resolution (Qr72) reconstructions, the Temporal Bone (Hr84) protocol provided markedly superior delineation of fine plaque morphology in the smallest plaque inlay (LAP4mm) using PCD-CT. This phantom design simulates a true-to-scale 4 mm coronary plaque, underscoring the relevance of these findings to real coronary artery dimensions.

Source:
@Bálint Szilveszter, Kolossváry M, Kubovje A, et al. Mixed coronary plaque phantom analysis by photon-counting CT: impact of calcium and iodine on low-attenuation plaque detection. European Heart Journal – Imaging Methods and Practice. 2026;4(3):qyag119.

Protocol (PCCT)

Parameter	Standard mode	UHR mode	High-resolution reference standard
	Cardiac, sequential, half-rotation	Cardiac, sequential, half-rotation	Temporal Bone, helical, full-rotation
Tube voltage (kVp)	120	120	140
Kernel	Qr40 & Qr72	Qr40 & Qr72	Hr 84
Field of view (mm)	102	102	100
Single collimation width (mm)	0.4	0.2	0.2
Rotation time (s)	0.25	0.25	0.5
Matrix size	512 × 512	512 × 512	768 × 768
Pixel dimensions (mm × mm)	0.20 × 0.20	0.20 × 0.20	0.13 × 0.13
Computed tomography dose index volume (mGy)	13.98	14.79	55.05
Energy levels (keV)	40,70,100,130, T3D	T3D	T3D
Focal spot (mm)	0.8/1.2	0.8/1.2	0.6/0.7