Electrocardiographically gated multi-detector row CT for assessment of valvular morphology and calcification in aortic stenosis

PURPOSE: To evaluate the applicability and image quality of nonenhanced and contrast material-enhanced multi-detector row computed tomography (CT) combined with retrospective electrocardiographic (ECG) gating for visualization of the aortic valve, determination of aortic valve morphology and diameter of the aortic valve annulus, and assessment of the degree of valvular calcification in patients with aortic valve stenosis, as compared with results of surgery and echocardiography. MATERIALS AND METHODS: Prior to surgical valve replacement, 25 patients with aortic valve stenosis and sinus rhythm underwent nonenhanced (n = 15) and contrast-enhanced (n = 25) retrospectively ECG-gated multi-detector row CT. Two readers working in consensus evaluated image quality and assessed valvular morphology and the degree of valvular calcification. In addition, the diameter of the aortic valve annulus was measured. Results were compared with surgical and echocardiographic findings by using the paired sign test, kappa statistics, and the method of Bland and Altman. RESULTS: The aortic valve could be visualized nearly free of motion artifacts on all multi-detector row CT images. Image quality and diagnostic confidence for classification of aortic valve morphology were significantly superior on contrast-enhanced rather than nonenhanced images (P = .004 and P = .006, respectively). Nonenhanced and contrast-enhanced CT showed good agreement with surgical findings with regard to quantification of the degree of aortic valve calcification (kappa = 0.77 and kappa = 0.74, respectively). Measurement of the diameter of the aortic valve annulus was more reliable on contrast-enhanced images. CONCLUSION: Contrast-enhanced retrospectively ECG-gated multi-detector row CT allows determination of aortic valve morphology, measurement of the diameter of the aortic valve annulus, and assessment of the degree of aortic valve calcification in patients with aortic stenosis. (C) RSNA, 2002.