目的 通过128层螺旋CT探讨心 肌桥-壁冠状动脉(MB-MCA)双期狭窄程度 及临床意义。方法 回顾性分析117例诊 断为前降支MB-MCA患者的CT冠状动脉图 像，记录MB-MCA发生位置、类型、收缩期 狭窄程度、舒张期狭窄程度，评估不同 类型间双期狭窄程度的差异、收缩期狭 窄程度与壁冠状动脉近端粥样硬化斑块 发生率的差异；评价其中58例单纯性MBMCA的舒张期狭窄程度与临床症状及运动 平板试验关系。结果 117例前降支MB-MCA 中，收缩期狭窄率≥50%的29例，舒张期 狭窄率≥50%的14例，二者比较有统计学 意义(P<0.05)。117例MB-MCA中不完全型 46例，完全型71例，两型的收缩期狭窄率 及舒张期狭窄率的差异均有统计学意义 (P<0.05)。MB-MCA舒张期狭窄率较高的患 者临床表现及平板运动试验阳性率高。随 着收缩期狭窄程度升高，MB-MCA近端动脉 粥样硬化病变发生率增加(P<0.05)。结 论 MCA在收缩期及舒张期皆有不同程度的 狭窄，此狭窄程度与MB-MCA的类型有关。 MCA的收缩期狭窄程度越高，其近端更易 发生动脉粥样硬化斑块；MCA的舒张期狭 窄会引发冠状动脉功能学改变。

Objective To study the degree of stenosis of myocardial bridge- mural coronary artery (MB-MCA) by 128-slice spiral CT in systolic and diastolic phases and its clinic. Methods 117 patients with MB-MCA were retrospectively analyzed in this study. We recorded the position, type, degree of MB-MCA in systolic and diastolic phase, evaluated the difference of stenosis between different types and relationship between systolic stenosis and the incidence of atherosclerotic plaque in the proximal wall of the coronary artery. The relationship between the extent of diastolic stenosis of 58 patients with simple MBMCA and the clinical symptoms and Treadmill exercise test was evaluated. Results Among the 117 patients with MB-MCA, 29 cases had a systolic stenosis rate of ≥ 50% and 14 cases had a stenosis in the diastolic (P<0.05). In the 117 cases of MB-MCA, there were 46 cases of incomplete type and 71 cases of complete type. The stenosis was statistically significant in systolic and diastolic (P<0.05). MB-MCA had a higher rate of diastolic stenosis in patients with clinical manifestations and Treadmill exercise test positive rate. With the increase of systolic stenosis, the incidence of proximal atherosclerosis in MB-MCA increased (P<0.05). Conclusion MB-MCA have varying degrees of stenosis, the degree of stenosis was related to the type of MB-MCA in the systolic and diastolic phases. The higher degree of systolic stenosis of MCA, the more likely to occur at the proximal atherosclerotic plaque; stenosis of MB-MCA in diastolic can lead to coronary artery function changes.