PURPOSE: The aim of our study was to compare the calcium content measured by non-enhanced multidetector-row-computed tomography (MDCT) between patients with significant stenosis of bicuspid (BAV) and tricuspid aortic valve (TAV). Another aim of our study was to assess the accuracy of the non-enhanced MDCT to distinguish BAV and TAV based on the calcified plaque morphology, and to compare the results with the transesophageal echocardiography. SUBJECTS AND METHODS: A retrospective analysis of prospectively collected data was performed. Consecutive patients with symptomatic aortic stenosis (AS) admitted to hospital for evaluation before valve surgery underwent clinical evaluation, transthoracic and transesophageal echocardiography, and non-enhanced examination with the 64-detector-row CT using prospective ECG triggering with data acquisition in diastolic phase. The data acquisition started at 55% of the R-R interval. The patients were examined in the supine position in mild inspiration. Data were evaluated using dedicated software for calcium scoring, the volume of calcifications and calcium content were obtained. RESULTS: Thirty-seven patients (20 males, age 48-83 years) were enrolled. BAV was present in 13 patients, TAV in 24 patients. The calcium score in patients with severe AS (mean gradient >50 mmHg) was higher than in those with moderate AS (1123+/-616 mg versus 634+/-475, P=0.011). Significant correlation between the calcium scores and transaortic gradients was found (r=0.53, P=0.002). The patients with BAV did not differ significantly from those with TAV in the AS severity (58+/-13 versus 53+/-20 mmHg), nor in the valve calcium score (1168+/-717 versus 795+/-530 mg, P=0.093). The overall sensitivity to detect BAV in patients with calcified severe AS was 0.923 (12/13) and specificity 0.958 (23/24). The overall accuracy was 0.945 (35/37). CONCLUSION: We observed higher calcium score in patients with severe AS than with moderate AS. However, no difference in aortic valve calcium score between BAV and TAV was found. Thus, in our sample, the aortic valve calcium score correlated with AS severity, not with aortic valve morphology. Based on the calcified plaque space relationship, the aortic BAV and TAV could be distinguished in most cases.