Ultra-high resolution photon-counting detector coronary CT angiography: diagnostic accuracy in patients with high Agatston scores
Tristan T. Demmert, Konstantin Klambauer, Lukas J. Moser, Jonathan Michel, Markus Kasel, Robert Manka, Victor Mergen, Thomas Flohr, Matthias Eberhard, Hatem Alkadhi
Abstract
OBJECTIVES: Severe coronary artery calcification leads to blooming artifacts in conventional coronary CT angiography (CCTA), which may reduce diagnostic accuracy. Ultra-high resolution (UHR) photon-counting detector CT (PCD-CT) reduces calcium blooming. This study aimed to evaluate the diagnostic performance of UHR CCTA with PCD-CT for detecting coronary stenoses in patients with a high coronary calcium burden compared to invasive coronary angiography (ICA). MATERIALS AND METHODS: In this IRB-approved single-center study, patients with Agatston scores > 600 were included, who underwent ICA and coronary UHR PCD-CT angiography within 2 months. 94% of patients underwent CT prior to transcatheter aortic valve replacement. Coronary arteries were graded for diameter stenosis severity (> 50, > 70%) by two blinded, independent readers. Accuracy, sensitivity, and specificity of CCTA were calculated using ICA as the reference standard. Subgroup analyses were performed across Agatston score groups (600-999, 1000-1999, 2000-2999, and > 3000). RESULTS: 62 patients (mean age, 76 ± 9 years, 16 women) were included. The median Agatston score was 2423 (IQR: 1085-3340). Across all Agatston categories, CCTA demonstrated high diagnostic accuracy and strong agreement with ICA (Cohen's kappa 0.71-1.00). In patients with Agatston scores > 3000 (n = 18), the diagnostic performance of coronary UHR PCD-CT angiography for detecting > 50% (sensitivity 92-100%, specificity 83-100%) and > 70% diameter stenosis (sensitivity 88-100%, specificity 89-100%) remained high for both readers. There was no correlation between the Agatston score and diagnostic error (p > 0.05). CONCLUSION: UHR CCTA with PCD-CT provides high diagnostic performance even in patients with extensive coronary calcifications. KEY POINTS: Question In patients with severe coronary calcification, conventional coronary CT angiography often suffers from blooming artifacts, reducing accuracy and causing unnecessary invasive procedures. Findings Ultra-high resolution coronary angiography with photon-counting detector CT showed high sensitivity and specificity for detecting stenoses, even at Agatston scores > 3000. Clinical relevance Ultra-high resolution coronary CT angiography enables accurate noninvasive detection of stenoses in heavily calcified vessels, potentially reducing invasive coronary angiography.