Abstract 13748: Feasibility Of Quantitation Coronary And Aortic Valve Calcification In Virtual Non-contrast Images From Dual-energy Delayed Ct Scans In Patients With Severe Aortic Stenosis

Abstract

Introduction: Increased extracellular volume (ECV), is a prognostically important marker of myocardial fibrosis in patients with severe aortic stenosis (AS). ECV can be assessed during transcatheter aortic valve replacement planning CT (TAVR CT) scan by adding a dual-energy CT (DECT) delayed image. TAVR CT scans routinely include a traditional non-contrast scan (TNC) for coronary artery calcium (CAC) and aortic valve calcium (AVC) scoring. Virtual non-contrast (VNC) images, derived from the DECT could replace TNC for CAC and AVC scoring, and reducing radiation and scan time. We examined the adaptability of VNC as a substitute for TNC by comparing CAC and AVC scoring based on VNC from delayed DECT scans compared to TNC in severe AS patients. Methods: We enrolled 27 severe AS patients who underwent TNC CAC scan and delayed DECT scan as part of TAVR CT using a dual-source scanner (Somatom Flash, Siemens). VNC was reconstructed with postprocessing software (Syngo Dual Energy, Siemens). CAC was categorized as 0, 1-99, 100-399, 400-999 and ≥1,000. Severe AVC was defined as >2,200 for men and >1,200 for women. Results: Both CAC and AVC scores in VNC demonstrated excellent correlation with TNC (r=0.975 and 0.982). The CAC score was significantly lower in VNC compare to TNC (745.2 ± 923.6 vs. 1006.4 ± 1116.9, p<0.001). AVC score did not significantly differ between VNC and TNC (2000.8 ± 2791.6 vs. 1911.5 ± 2186.8, p=0.567). Three patients (3/27) were categorized to a CAC category one grade lower than TNC by VNC DECT (Figure). One patient with non-severe AVC by TNC was misclassified as having severe AVC by VNC (1/27) (Figure). Conclusions: VNC DECT underestimates CAC compared to TNC, but the differences in CAC score rarely resulted in categorical discordance in severe AS patients. VNC from DECT delayed scan for ECV assessment can assign patients to the correct cardiovascular risk categories based on CAC and performs adequately for clinically meaningful AVC scoring in severe AS patients.