Diagnostic Value of Calcium Score Derived From Virtual Noncontrast, Non–ECG-gated Dual-energy CT as an Indicator of Severe Aortic Stenosis

STUDY TYPE: Retrospective monocentric study. PURPOSE: To estimate the probability of severe aortic stenosis(SAS) by calculating the aortic valve calcium score (AVCS) using virtual noncontrast (VNC) reconstructions derived from non-ECG-gated dual-energy computed tomography (DECT) scans. MATERIALS AND METHODS: This study retrospectively included 59 patients who underwent DECT scans for noncardiac indications and presented with visible aortic valve calcifications. AVCS was calculated on VNC images using semiautomatic software. All patients had an echocardiogram performed within 12 months before or after the DECT scan. We then analyzed the correlation between AVCS values and the degree of aortic stenosis. RESULTS: Both male and female patients with SAS had a significantly higher mean AVCS (919.2 AU, SD=1262.4) compared with those with nonsevere aortic stenosis (NSAS) (127.9 AU, SD=278.6). AVCS demonstrated good diagnostic performance in distinguishing between severe and nonsevere AS in both female and male (AUC=0.91 and 0.95, respectively). Estimated thresholds values showed high sensitivity in both genders, with good specificity in men, and moderate in women. When analyzed irrespective of gender, AVCS demonstrated good ability to distinguish severe AS from mild and no stenosis (AUC=0.926), and moderate ability to distinguish moderate AS from mild and no stenosis (AUC=0.781). However, it lacked statistical significance in discriminating severe and moderate AS (AUC=0.714, P=0.1325). CONCLUSIONS: Aortic Valve Calcium Score obtained on VNC images from DECT examinations is a promising method for noninvasively differentiation between severe and nonsevere aortic stenosis, which could be potentially useful in patients who have undergone examinations for noncardiac indications.