Background Recently, it has been reported that coronary computed tomographic angiography(CCTA) is sensitive diagnostic tool for detecting myocardial bridge. However, it is unknown whether CCTA is feasibile for evaluating severity of myocardial bridge. So we examined the feasibility of CCTA for predicting extent of myocardial bridge in patients with typical angina and normal coronary artery. Method We collected patients who had typical angina and normal coronary artery but myocardial bridge of left anterior descending artery(LAD) detected in invasive coronary angiography. These patients also had a 64 slice multidetector CCTA. Myocardial bridge parameters of intramuscular segment thickness, length and location were evaluated in CCTA and correlated with that measured in QCA. Significant coronary artery compression by myocardial bridge was defined as more than 50% systolic reduction of luminal diameter which was measured by quantitative coronary angiography(QCA). Result Total of 41 patients were included in this study. The patients��� age was 60짹9 years old and male patients was 21(51%). Thirty(73%) patients had more than 50% systolic reduction of luminal diameter by myocardial bridge. The location of myocardial bridge was mid LAD 17(42%), mid to distal LAD 10(24%) and distal LAD 14(34%). Intramuscular segment length of myocardial bridge measured by CCTA ranged from 7 to 33 mm (17.8짹6.3mm) and showed good positive correlation with QCA measurement(r=0.601, p<0.001). Intramuscular segment thickness ranged from 0.3 to 3.9 mm(2.1짹1.0mm) and correlated very well with percent reduction of luminal diameter in systolic period measured by QCA(r=0.504, p=0.01). Intramuscular segment thickness more than 2.0mm measured by CTCA was optimal cut off value(sensitivity:70%, specificity:73%) to predict significant coronary artery compression by myocardial bridge, yielding an area under the curve of 0.75(95% CI 0.52-0.97). Conclusion The thickness of myocardial bridge measured by CCTA correlated well with systolic reduction of luminal diameter measured by QCA. CCTA may predict severity of myocardial bridge in patients with typical angina and normal coronary artery.