Objective:To evaluate the clinical significance of myocardial bridge at coronary CT angiography(CTA)comparing with conventional coronary angiography(CCA).Methods:135 patients who underwent coronary CT angiography were included in this study

while 50 of these patients underwent conventional coronary angiography within a time interval of two weeks.The depiction rate

precise location

length

depth

systolic stenosis and the situation of the nearby arteries were evaluated in CTA.The depiction rate

precise location

length and the degree of systolic stenosis were evaluated in CCA.Pearson correlation analysis was used to analyze the relation of the degrees of systolic stenosis between two methods and the relation between length

depth and the degree of systolic stenosis as assessed with CT.The paired t-test was used to compare the degrees of systolic stenosis between two methods.Results:With CT

MB was detected in 91(67.4%)of 135 patients

in which the mid left anterior descending artery(LAD)was the most common coronary artery involved (60.2%).In 50 patients who underwent both CT and CCA

the depiction rate of MB was 24%with CCA and 68%with CT.With CT

the significant correlations were both found between the degree of systolic stenosis and length(r= 0.282)

depth(r=0.561)of the tunneled segment

while a significant correlation was found between the degrees of systolic stenosis with CTA and CCA(r=0.785).The difference between the two motheds were not significant statistically.Conclusion:64-section CT coronary angiography enables the depiction of the morphologic feathers of MB and the tunneled segment.Length and depth of the tunneled segment correlated with the degree of systolic stenosis of MB.Comparing with CCA

the depiction rate of MB can be obviously improved by CTA

but the vecacity of the degree of systolic stenosis with CTA can not reach CCA.