Application of 256 layer CT coronary angiography in the study of relationship between myocardial bridge and myocardial ischemia

Abstract

Objective To investigate the relationship between myocardial bridge (MB) and myocardial ischemia by 256-slice CT coronary angiography (CTCA). Methods The images of 120 cases of simple MB diagnosed by 256-slice CTCA were retrospectively analyzed . They were divided into superficial type and deep type. The length of MB in different phase was measured, and the stenosis degree of MCA in systole was calcuated, and the differences of MB type in different Noble grade were compared. Results The length of superficial and deep type MB in diastole were respectively (19.48±8.20)mm and (22.25±8.21)mm, there was no significant difference between the two groups(t=1.81, P>0.05); the length in systole were respectively (19.56±7.37)mm and (22.63±9.82)mm, there was no significant difference between the two groups(t=1.96, P>0.05); the stenosis degree of MCA in systole were respectively (32.06±11.89)% and (44.11±12.15)%, there was significant difference between the two groups(t=5.38, P<0.01). The deep type of MB in grade 2 and 3 (17/23, 1/1) was significantly higher than that in grade 1 (29/96). The difference between grade 1 and 2(χ2=14.946, P<0.01), grade 1 and grade 2 + grade 3 was significant (χ2=16.167, P<0.01). Conclusions MB preferentially occurs in the middle segment of anterior descending branch. The thickness and type of MB, the stenosis degree of MCA in systolic are closely correlated with myocardial ischemia, the grade 2 and 3 of MCA in systolic were more likely to occur myocardial ischemia, but the length of MB has no significant correlation with myocardial ischemia. Key words: Myocardial bridge; Mural coronary artery; Myocardial ischemia; Coronary artery imaging