核素心肌灌注显像和CT冠状动脉造影检测冠状动脉心肌桥所致心肌血液供应异常

Detection of abnormal myocardial blood supply caused by myocardial bridge using myocardial per fusion imaging and CT coronary angiography

目的利用SPECT／CT完成同机核素MPI和CTCA，探讨冠状动脉（简称冠脉）心肌桥（MB）对心肌血液供应的影响。方法回顾性分析2008年3月至2013年3月间294例以胸闷、胸痛或心悸为主要症状、接受MPI及同机CTCA检查的患者资料，筛选出冠脉MB患者49例[男26例，女23例，年龄32～85（55．4±16．6）岁]。统计MB和缺血发生部位；将MPI和CTCA图像进行融合，对融合图像上MB．壁冠脉穿行心肌缺血区域、且CAG证实该区域供血冠脉不存在粥样斑块所致管腔狭窄者，判定心肌缺血为MB所致。利用z。检验比较不同部位MB引发心肌缺血改变的发生率差异。结果49例冠脉MB患者中，MB位于前降支近段3例，前降支中段34例，前降支远段4例，间隔支3例，回旋支远段2例，中间支I例，右冠脉近中段2例；MPI显示心肌缺血41例（缺血部位46处），其中心尖部3例，前壁心尖部5例，前壁中部17例，间隔心尖部4例，前间隔中部3例，前侧壁中部2例，下侧壁中部2例，下侧壁基底段4例，下壁近心尖部3例，下壁基底段3例；融合图像示MB引发的心肌缺血有32例，其中23例由前降支中段MB所致。MB位于好发部位组（前降支中段，34例）与非好发部位组（15例）的心肌缺血发生率分别为67．6％（23／34）和60．0％（9／15），差异无统计学意义（x2=0．27，P〉0．05）。结论左冠脉前降支中段是MB的好发部位，不同部位的MB引发心肌缺血的发生率无显著差异。MPI／CTCA融合影像可同时探测心肌缺血和冠脉MB的部位，判断MB对心肌血液供应的影响。

Objective To evaluate the cause of ischetnia related to myocardial bridge （MB） by using SPECT/CT MPI and CTCA. Methods A total of 294 patients with chest pain, tightness or palpitation un dergoing both CTCA and MPI were retrospectively enrolled in this study from March 2008 to March 2013. Among them, 49 patients （26 males, 23 females, age： 32-85（55.4＋16.6） years） had MB. Locations of MB and myocardial ischemia were recorded. Fused MPI/CTCA was analyzed. If there was no mural atherosclerotic plaque-related stenosis on CAG at the same location of coronary artery where ischemic myocardium was found, then MB was considered as the ischemic cause. Myocardial ischemia rates of different MB locations were compared by X2 test. Results Among 49 patients with MB, 3 cases had MB in proximal segment of LAD, 34 in mid LAD, 4 in distal LAD, 3 in septal branch, 2 in distal LCX, 1 in intermedius, and 2 in mid RCA. There were 41 cases with myocardial ischemia. Myocardial ischemia in 32 cases was caused byMB, including 23 caused by MB in mid LAD. The myocardial ischemia rates of the most common MB loca- tion （mid LAD, n=34） and other locations （n= 15） were not significantly different （67.6% （23/34） vs 60.0% （9/15）, X2= 0.27, P〉0.05）. Conclusions MB is commonly found in the mid LAD. The myocar dial ischemia rates caused by MB is not related the MB location. Hybrid MPI/CTCA could evaluate the sites of coronary MB and myocardial ischemia simultaneously and therefore may be useful to evaluate the relationship between MB and myocardial ischemia.