Aortic Regurgitation: Assessment with 64-Section CT

Abstract

To prospectively evaluate diagnostic accuracy of 64-section computed tomography (CT) for evaluation of aortic regurgitation (AR), with transthoracic echocardiography (TTE) as reference. The institutional review board approved this study; written informed consent was obtained. Thirty patients (23 men, seven women; mean age, 56.6 years) with AR underwent TTE and retrospective electrocardiographically gated 64-section CT. CT data sets were reconstructed in 5% steps from 40% to 90% of R-R interval for analysis. Maximum regurgitant orifice area (ROA) in diastole was planimetrically measured with CT, and measurements were compared with semiquantitative classification with TTE (Spearman rank order correlation coefficients). Receiver operating characteristic (ROC) curves were calculated for differentiation between degrees of AR with ROA measurements. Dimensions of the aortic root and left ventricular parameters were compared (Pearson correlation analysis). A significant correlation was observed between CT planimetric size of ROA (mean, 62 mm2+/-63 [standard deviation]; range, 6-224 mm2) and TTE classification of mild, moderate, and severe AR (r=0.84, P<.001). With ROC analysis, discrimination between degrees of AR with CT was highly accurate when cutoff ROAs (25 mm2 and 75 mm2) were used. A significant correlation was observed between methods in dimensions of aortic annulus (mean, 29.0 mm+/-4.6), sinus of Valsalva (mean, 38.3 mm+/-8.6), and ascending aorta (mean, 37.2 mm+/-8.0); mean values were 27.4 mm+/-4.9 (r=0.76, P<.001), 37.7 mm+/-8.6 (r=0.94, P<.001), and 38.2 mm+/-7.9 (r=0.96, P<.001), respectively. Mean end-systolic volume (67 mL+/-38), end-diastolic volume (149 mL+/-48), and ejection fraction (57%+/-13) at CT correlated well with mean results at TTE (65 mL+/-36 [r=0.96, P<.001], 140 mL+/-48 [r=0.91, P<.001], 56%+/-13 [r=0.98, P<.001], respectively). Results of assessment of AR with 64-section CT are similar to those with TTE.