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心肌桥(myocardial bridge,MB)是指覆盖在心外膜冠状动脉上的心肌纤维束,被心肌纤维束覆盖的冠状动脉称为壁冠状动脉(muralcoronary artery,MCA),而这一复合体统称为MB-MCA。MB-MCA被认为是一种良性的冠状动脉先天性解剖变异,可导致部分患者心肌缺血,甚至猝死[1],因此,早期准确地诊断及评价MB-MCA,有助于预防严重并发症。多层螺旋CT的空间、时间分辨力高,具有无创性,评价冠状动脉病变准确、快速,且能直观显示MB-MCA形态学特征,包括MCA的部位、心肌覆盖范围、血管狭窄程度以及MB的厚度,并同时可发现桥近、远段及MCA本身有无粥样硬化病变,因此,其在诊断MB-MCA相关冠状动脉病变上具有重要的临床应用价值。本研究拟利用640层螺旋CT冠状动脉成像对MB-MCA的形态学及相关功能改变进行量化分析,并探讨MB-MCA与冠状动脉粥样硬化的相关性。
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186例患者中共发现56例(70段)存在MB-MCA,约占30.1%,其中45例(80.4%)为单一MCA,8例(14.3%)为2段受累,3例(5.3%)为3段受累。70段MB-MCA的位置如表 1所示。
部位 数量 平均厚度(x±s)/mm 平均长度(x±s)/mm 浅表型 深厚型 LAD2 48(68.6%) 2.68±0.68 21.42±6.42 31 17 LAD1-3 9(12.9%) 2.33±0.64 19.86±5.98 5 4 LCX 3(4.3%) 2.35±0.48 20.04±6.26 2 1 D1-2 5(7.1%) 2.14±0.38 17.23±5.23 3 2 OM 3(4.3%) 2.46±0.58 16.48±5.32 2 1 RCA 2(2.8%) 2.13±0.42 16.58±4.96 1 1 合计 70(100%) 2.32±0.51 18.48±5.24 44 26 注:表中,LAD2:左前降支2段;LAD1-3:左前降支近、中、远段;LCX:左回旋支;D1-2:第l、2对角支;OM:钝缘支;CA:右冠状动脉。 表 1 56例患者70段心肌桥-壁冠状动脉的分布及测量结果
Table 1. Distribution and measured results of 70 segments of myocardial bridge-mural coronary artery in 56 patients
CPR图像示MCA走行较平直,在心肌内行走一段距离后又浅露于心肌表面,即“上下台阶”征(图 1中A)。70段MB-MCA平均MB厚度为(2.32±0.51)mm,MCA平均长度为(18.48±5.24)mm。根据MB的厚度,70段MB-MCA中浅表型44段(占62.9%),深厚型26段(占37.1%)(图 1中B、C);MB-MCA具体分布和测量结果见表 1。
图 1 不同冠心病患者的多层螺旋CT图 A:患者女性,58岁,左前降支见多发节段性心肌桥,呈上下台阶样改变;B~C:患者均为男性,69岁和56岁,分别表现为左前降支2段浅表型和深厚型心肌桥,心肌桥厚分别为1 mm和2.5 mm,壁冠状动脉近侧见少许粥样斑块。D~E:患者男性,62岁,D和E分别为多平面重组和容积再现图,表现为左前降支2段浅表型心肌桥,收缩期壁冠状动脉管腔Ⅱ级狭窄;F:患者男性,74岁,左前降支2段浅表型心肌桥,壁冠状动脉近侧见混合型粥样斑块。
Figure 1. Multi-detector spiral CT imagings of different coronary disease patients
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48段位于LAD2的MB-MCA剔除5段横断面血管边缘模糊的病例,最终对43段进行定量分析,详见表 2。MB的△厚度范围为1.02~1.86 mm,平均为(1.64±0.56)mm,△直径范围为0.80~2.02 mm,平均为(1.21±0.36)mm。△厚度和△直径在心脏收缩期和舒张期差异具有统计学意义(t=2.84、3.38,P均<0.05),且两者变化呈反比趋势。43段MB-MCA中,10段(23.3%)为Ⅰ级狭窄,28段(65.1%)为Ⅱ级狭窄,5段(11.6%)为Ⅲ级狭窄(图 1中D、E)。
量化指标 Dd/mm Ds/mm 差值/mm 变化率/% MB厚度 2.56±0.52 4.24±0.92 1.64±0.56 68.6 MCA直径 2.36±0.46 1.46±0.24 1.21±0.36 57.8 注:表中,MB:心肌桥;MCA:壁冠状动脉;Dd:舒张末期内径,Ds:收缩末期内径。 表 2 左前降支2段的心肌桥-壁冠状动脉定量分析结果(x±s)
Table 2. Quantitative analysis of myocardial bridge-mural coronary artery of left anterior descending(x±s)
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70段MB-MCA中共发现48段存在粥样斑块,占68.6%;其粥样斑块发生在MB-MCA近侧者42段(87.5%),远侧者6段(12.5%),两者之间的差异具有统计学意义(t=3.12,P<0.05),MCA本身未发现存在粥样斑块(图 1中B、C、F)。
640层螺旋CT冠脉成像对心肌桥-壁冠状动脉的形态学量化评价及粥样硬化相关性分析
Quantitative evaluation of morphological characteristics and their correlation with atherosclerosis of the myocardial bridge-mural coronary artery by 640 multi-detector spiral CT
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摘要:
目的 利用640层螺旋CT冠状动脉成像对心肌桥-壁冠状动脉(MB-MCA)的形态学特征行定量分析,并探讨其与粥样硬化的关系。 方法 收集行冠状动脉成像的186例疑似冠心病患者的影像资料进行分析,若MB-MCA的诊断成立,描述MB-MCA的分布和分型,并在心脏收缩期和舒张期分别记录位于左前降支2段(LAD2)的MB-MCA的厚度以及血管直径,计算其在收缩期及舒张期的变化情况;同时分析MB-MCA粥样斑块情况。 结果 186例患者中56例(70段)存在MB-MCA,其中48段(68.6%)位于LAD2;70段MB-MCA中浅表型有44段(62.9%),深厚型有26段(37.1%)。位于LAD2的MB-MCA厚度和直径在心脏收缩期和舒张期差异均有明显变化,差异具有统计学意义(t=2.84、3.38,P均 < 0.05);43段位于LAD2的纳入分析的MB-MCA中有28段(65.1%)为Ⅱ级狭窄。70段MB-MCA中共48段(68.6%)存在粥样斑块,其中近侧者42段(87.5%),明显高于远侧者6段(12.5%),两者之间的差异有统计学意义(t=3.12,P < 0.05)。 结论 640层螺旋CT不仅能直接显示MB-MCA的存在,同时能对其形态特点、伴随心动周期动态变化情况行量化分析,具有较高的临床价值。 -
关键词:
- 体层摄影术, 螺旋计算机 /
- 冠状血管造影术 /
- 冠状血管畸形 /
- 心肌桥-壁冠状动脉
Abstract: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. -
图 1 不同冠心病患者的多层螺旋CT图 A:患者女性,58岁,左前降支见多发节段性心肌桥,呈上下台阶样改变;B~C:患者均为男性,69岁和56岁,分别表现为左前降支2段浅表型和深厚型心肌桥,心肌桥厚分别为1 mm和2.5 mm,壁冠状动脉近侧见少许粥样斑块。D~E:患者男性,62岁,D和E分别为多平面重组和容积再现图,表现为左前降支2段浅表型心肌桥,收缩期壁冠状动脉管腔Ⅱ级狭窄;F:患者男性,74岁,左前降支2段浅表型心肌桥,壁冠状动脉近侧见混合型粥样斑块。
Figure 1. Multi-detector spiral CT imagings of different coronary disease patients
表 1 56例患者70段心肌桥-壁冠状动脉的分布及测量结果
Table 1. Distribution and measured results of 70 segments of myocardial bridge-mural coronary artery in 56 patients
部位 数量 平均厚度(x±s)/mm 平均长度(x±s)/mm 浅表型 深厚型 LAD2 48(68.6%) 2.68±0.68 21.42±6.42 31 17 LAD1-3 9(12.9%) 2.33±0.64 19.86±5.98 5 4 LCX 3(4.3%) 2.35±0.48 20.04±6.26 2 1 D1-2 5(7.1%) 2.14±0.38 17.23±5.23 3 2 OM 3(4.3%) 2.46±0.58 16.48±5.32 2 1 RCA 2(2.8%) 2.13±0.42 16.58±4.96 1 1 合计 70(100%) 2.32±0.51 18.48±5.24 44 26 注:表中,LAD2:左前降支2段;LAD1-3:左前降支近、中、远段;LCX:左回旋支;D1-2:第l、2对角支;OM:钝缘支;CA:右冠状动脉。 表 2 左前降支2段的心肌桥-壁冠状动脉定量分析结果(x±s)
Table 2. Quantitative analysis of myocardial bridge-mural coronary artery of left anterior descending(x±s)
量化指标 Dd/mm Ds/mm 差值/mm 变化率/% MB厚度 2.56±0.52 4.24±0.92 1.64±0.56 68.6 MCA直径 2.36±0.46 1.46±0.24 1.21±0.36 57.8 注:表中,MB:心肌桥;MCA:壁冠状动脉;Dd:舒张末期内径,Ds:收缩末期内径。 -
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