Diagnostic Value of Cardiac CT in the Evaluation of Bicuspid Aortic Stenosis: Comparison With Echocardiography and Operative Findings

OBJECTIVE. This study was conducted to assess the diagnostic value of cardiac CT for the evaluation of patients with bicuspid aortic valve disease. MATERIALS AND METHODS. Fifty consecutive patients with aortic stenosis who underwent surgical valve repair between September 2005 and November 2006 were examined by ECG-gated CT and echocardiography. A 64-MDCT scanner was used. The image findings regarding the number of leaflets (bicuspid or tricuspid) were compared against the intraoperative findings and were statistically analyzed by one-way univariate analysis of variance. The aortic valve area (AVA) was also measured by CT and echocardiography, and the measured values were statistically compared by use of the paired Student's t test. RESULTS. Seventeen patients had a bicuspid aortic valve, and 33 had a tricuspid aortic valve. In 10 of the 50 patients, echocardiography was unable to depict the type of aortic valve because of extensive calcification. The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of a bicuspid aortic valve were 76.5%, 60.6%, 68.4%, and 95.2%, respectively, for echocardiography and 94.1%, 100%, 100%, and 97.1%, respectively, for CT. The CT findings were not significantly different from the intraoperative findings (p = 0.99), but the echocardiographic findings were (p < 0.05). The AVA measurements obtained by CT and echocardiography were 0.940 +/- 0.44 cm(2) and 0.659 +/- 0.234 cm(2), respectively, showing a significant difference (p < 0.05). CONCLUSION. ECG-gated cardiac CT is useful for the accurate morphologic assessment of bicuspid aortic stenosis, especially in patients with severe valve calcification.