Spectral Photon-Counting Detector Coronary CTA With Reduced Radiation and Contrast Media Doses in Inflammation-Associated Coronary Artery Disease: A Prospective Study.

Patients with inflammation-associated coronary artery disease (CAD) may exhibit rapid progression and require regular coronary imaging. To evaluate the diagnostic performance of spectral photon-counting detector (PCD) coronary CTA with reduced radiation and contrast media doses for detecting coronary stenosis and in-stent restenosis in patients with inflammation-associated CAD. This prospective study enrolled patients with inflammation-associated CAD from January 2023 to March 2024. Participants underwent spectral PCD coronary CTA using prospectively ECG-triggered sequential acquisition and an individualized low-dose contrast media protocol. Virtual monoenergetic images (VMI) at 55 keV and polychromatic (T3D) images were reconstructed with matching parameters, including 0.4-mm slice thickness. Two readers independently assessed subjective (5-point Likert scales) and objective image quality measures; readers also assessed images for obstructive stenosis and in-stent restenosis (both ≥50%) in patients with invasive coronary angiography (ICA) available as reference. The analysis included 63 patients (mean age, 50.4±11.5 years; 45 women, 18 men). Median contrast media volume was 28.0 mL. Median DLP was 165.0 mG·cm. The 55-keV VMI, compared with T3D, showed better (p<.05) overall image quality, diagnostic confidence, SNR, and CNR in all three assessed vessels (e.g., right circumflex artery for reader 1: overall image quality of 4.5 vs 4.1, CNR of 12.1 vs 9.9). Diagnostic performance using ICA as reference was evaluated in 40 patients with 132 lesions and 75 stents. The 55-keV VMI, compared to T3D, demonstrated higher (p<.05) per-lesion accuracy for obstructive stenosis (reader 1: 96.2% vs 84.1%; reader 2: 97.0% vs 86.4%); these differences in accuracy were also observed for both readers for noncalcified and partly calcified plaques, lesions in mid and distal segments, and patients with BMI ≥24. The 55-keV VMI and T3D showed no significant difference (p>.05) in accuracy for in-stent restenosis (reader 1: 97.3% vs 96.0%; reader 2: 96.0% vs 94.7%). Spectral PCD coronary CTA, obtained using low radiation and contrast media doses and reconstructed using 55-keV VMI, demonstrated excellent diagnostic accuracy in detecting obstructive stenosis and in-stent restenosis in patients with inflammation-associated CAD. The proposed protocol could be used to guide clinical decision-making in inflammation-associated CAD.