Improved quantification of coronary stenosis in patients with high calcium scores using spectral reconstructions in coronary CT angiography

Abstract Background Coronary CT angiography has demonstrated reduced accuracy in patients with high calcium scores due to blooming artifacts, often resulting in overestimated stenosis. Purpose This study aimed to assess the impact of spectral reconstructions on coronary stenosis quantification in patients with high calcium scores (>500), utilizing invasive coronary angiography as the gold standard. Methods Twenty consecutive patients referred for coronary artery disease assessment underwent both coronary CT angiography and invasivecoronary angiography. Conventional 120 kV images, 100 keV virtual monoenergetic images, and iodine-no-water images were reconstructed. Two blinded operators independently reviewed the images. Lesions were qualitatively classified in both CCTA and invasive angiography as stenosis of 1-24%, 25-49%, 50-70%, and >70%. Results A total of 87 plaques were evaluated. Mean age was 72 years (SD=7.7) and 79% were male. Pre-test probability were low, medium and high in 15.8, 26.3% and 57.9% of patients respectively. Mean calcium score was 1662, with an average dose of 7.5 mSv (67.9% retrospective studies). Nitrates were administered in 89.5% of patients, and 47.4% received intravenous beta-blockers. Sensitivity, specificity, positive predictive value, and negative predictive value to detect lesions > 50% improved from 94%, 57%, 38%, 97% with conventional images to 94%, 82%, 59%, 98% with 100 keV virtual monoenergetic images. Conclusion Spectral reconstructions significantly enhance diagnostic accuracy in coronary CT angiography of severely calcified coronary arteries.