Background: The myocardial bridge (MB) is an intramural segment of coronary artery that is covered with myocardial tissue. The current diagnostic methods are coronary angiography, intravascular ultrasound and intracoronary Doppler, which are all invasive modalities. In this study, multidetector computed tomography (MDCT) was used to detect and evaluate the anatomical properties of the MB. Methods and Results: The 607 patients with suspected or known coronary artery disease underwent 64-slice MDCT. MB was diagnosed when an intramural segment of coronary artery was visualized on axial and multiplanar reconstruction images. The prevalence, length, myocardial thickness, and location were evaluated. Of the 607 patients, 39 (6.42%) had a MB. In 20 patients (52.6%), the MB was located in the mid left anterior descending artery. The length of tunneled artery was a mean 16.3 mm, from 6.9 mm to 30 mm, and the maximum thickness of the myocardial tissue was between 0.5 mm and 3.9 mm, with a mean of 1.8 mm. The length of the MB correlated significantly with thickness (P=0.049). Conclusions: The incidence of MB and its anatomical properties can be evaluated with MDCT, which might be a useful and noninvasive method of detecting this variant. (Circ J 2010; 74: 137 - 141)