Quantitative evaluation of morphological characteristics and their correlation with atherosclerosis of the myocardial bridge-mural coronary artery by 640 multi-detector spiral CT

Objective: To evaluate the morphological characteristics of myocardial bridge and mural coronary artery(MB-MCA) and to discuss the correlation between atherosclerosis and MB-MCA. Methods: The coronary artery imaging data of 186 with suspected coronary heart disease patients undergoing 640-slice computed tomography angiograms(CTA) were included. After the MB-MCA diagnosis was confirmed, the location and distribution of MB-MCA were recorded. The diameter and thickness of MB in the middle segment of LAD(LAD2) during the diastole and systole phases were also recorded, and changes in the MB-MCAs were calculated. In addition, the correlation between atherosclerosis and MB-MCA was discussed. Results: Among the 186 patients, 70 MB-MCAs were found in 56 patients(30.1%), whereas 48 MB-MCAs(68.6%) were located in LAD2. According to the MB thickness, 70 patients had MB-MCAs. Among which, 44 patients(62.9%) have the superficial type of MB-MCA, whereas 26(37.1%) have the deep type. The change in the average diameter of MCA in LAD2 from the systole phase to the diastole phase was obvious and statistically significant differences(t = 2.84, 3.38, both P < 0.05) were observed. Notably, 28(65.1%) of the patients have MCA diameters indicative of Grade Ⅱ stenosis. Among the 70 diagnosed MB-MCA, 48 segments have atherosclerosis. Atherosclerosis occurred in approximately 42(87.5%) of the MB-MCA patients, which was higher than the occurrence of distal segments in 6 MB-MCA patients(t = 3.12, P < 0.05). Conclusion: A 640-slice coronary CTA directly displays MB-MCA and can be used for the quantitative analysis of morphological characteristics and changes in the cardiac cycle of MB-MCA patients to provide reliable imaging data for clinical settings. (authors)