静息态下冠状动脉狭窄对左室壁透壁心肌灌注影响的640层CT研究

Effect of Coronary Artery Stenosis on the Transmural Extent of the Rest Myocardial Perfusion of Different Segments of Left Ventricular Wall Using 640 Slices CT

目的确定静息态下透壁心肌灌注指数(TPR)的正常值,并探讨静息态下不同分支的冠状动脉狭窄与各冠状动脉分支的不同狭窄程度对左室壁不同节段TPR的影响。方法 274例患者行Toshiba 640层CT检查,包括冠状动脉CTA及左心室室壁CT灌注(CTP)检查。根据冠状动脉狭窄程度及17节段进行分组。计算正常组及不同冠状动脉狭窄程度组之间相应节段内TPR是否存在差异,以及冠状动脉狭窄程度与相应节段TPR的相关性。结果前降支及左旋支病变对于左室壁心肌灌注影响较为明显,前降支狭窄主要影响中间段前壁(r=-0.288)、心尖段前壁(r=-0.263)及中间段间隔壁(r=-0.196),左旋支主要影响基底部前侧壁(r=-0.241)、基底部后侧壁(r=-0.279)及心尖段侧壁(r=-0.201),而右冠状动脉病变影响较小,主要影响中间段后壁(r=-0.195);冠状动脉中、重度狭窄组对于左室壁心肌灌注影响程度较大(P<0.05),轻度狭窄影响较小;左室前壁心肌灌注最易受到冠状动脉狭窄影响;在静息状态下前降支供血区域组、左旋支供血区域组及右冠状动脉供血区域组正常心肌和重度狭窄心肌平均TPR值分别为1.14±0.09和1.07±0.13、1.13±0.11和1.06±0.14、1.15±0.14和1.10±0.12。结论不同冠状动脉分支狭窄分别可以影响不同节段的心肌透壁灌注;不同冠状动脉狭窄程度可以不同程度地影响心肌的TPR,二者具有相关性;静息状态下TPR正常值大于负荷状态下TPR。本研究提供了TPR静息态下的正常值。

Objective To evaluate the influence of different branches and degree of the coronary artery stenosis on the myocardial transmural perfusion ratio of different segments of left ventricular wall, and to discuss the normal myocardial transmural perfusion ratio （TPR） of each territory of left ventricular wall in the rest state. Methods CT images of 274 pa- tients who received Toshiba 640 slices CT for CTA and CTP examination were analyzed retrospectively. Patients were divid- ed into groups according to the coronary artery stenosis degree and 17 segments. The differences of the relevant section TPR between the normal group and the groups of different coronary artery stenosis degree, and the relationship of coronary artery stenosis degree and the relevant section TPR were calculated. Results Effect of left anterior descending artery （LAD） and left circumflex coronary artery （LCX） stenosis on the TPR of left ventricular wall was more obvious. The anterior de- scending artery stenosis mainly influenced middle anterior segment （ r = - 0. 288 ）, apical anterior segment （ r = - 0. 263 ） and middle anteroseptal segment（ r = -0. 196 ）. Left circumflex coronary artery mainly influenced basal anterolateral seg- ment （ r = - 0.241 ）, basal inferolateral segment （ r = - 0.279） and apical lateral segment （ r = - 0.201 ）. Effect of right cor- onary artery was little which mainly influenced middle inferior segment. Effect of moderate and severe coronary artery steno- sis groups was more obvious than that of mild group. Anterior wall of left ventricular was more sensitive to coronary artery stenosis. The rest normal value of TPR and the mean TPR of the severe group in the territories of LAD , LCX and RCA wasrespectively（1.14±0.09and 1.07±0.13）,（1.13±0.11 and 1. 06 ± 0.14 ） and （1.15 ± 0.14 and l .10 ± 0.12 ） . Con- elusion Different branches of coronary artery stenosis can influence TPR of different segments. There is a relationship be- tween different degree of coronary artery stenosis and TPR of dominated segments. Rest normal value of TPR is bigger than that of the stress, which can provide a reference for clinical study.