99m　Tc－M　IBI心肌灌注断层显像对实验性心肌梗塞的评价

Assessment of Experimental Myocardial Infarction with 99mTc-MIBI SPECT

目的：评价９９ｍ锝一甲氧基异丁基异腈（９９ｍＴｃ－ＭＩＢＩ）ＳＰＥＣＴ显像对心肌梗塞范围的估测及硝酸甘油介入后对存活心肌检测的价值。材料和方法：７条杂种犬通过结扎冠状动脉造成心肌梗塞模型，分别在实验第一天及实验第七天行９９ｍＴｃ－ＭＩＢＩＳＰＥＣＴ静息显像及硝酸甘油介入９９ｍＴｃ－ＭＩＢＩ心肌显像。用圆周剖面法定量分析短轴６个断面心肌缺损面积大小。结果：末次显像缺损面积与病理梗塞面积有良好相关性（ｒ＝０．８６和ｒ＝０．８７分别为硝酸甘油介入前后心肌缺损面积与病理梗塞面积的相关系数），末次显像与首次显像相比缺损面积明显缩小（Ｐ＜０．０５），硝酸甘油介入后心肌显像的平均缺损面积在首次和末次显像均明显减小（Ｐ＜０．０１），且缺损区的平均计数在硝酸甘油介入后均明显增高（Ｐ＜０．０５）。结论：９９ｍＴｃ－ＭＩＢＩ心肌断层显像是了解急性心肌梗塞范围的较好手段及硝酸甘油介入９９ｍＴｃ－ＭＩＢＩＳＰＥＣＴ显像可以提高检测低灌注区残存的存活心肌。

Purpose: To test the feasibility of isonitrile tomography indemonstrating the size of myocardial damage and the approach for detecting viable myocardium with 99mTc-MIBI SPECT by nitroglycerin (NTG) administration before the tracer injection. Materiais and Methods: 7 mongrel dogs with acute myocardial infarctions by ligating coronary arteries underwent resting SPECT imaging and post-NTG imaging on the first and seventh day. The sizes of tracer uptake defect were quantified from circumferential profiles in 6 short-axis slices. Results: The final scintigraphic perfusion defect sizes correlated well with the pathologic sizes(r=0. 86 and r=0. 87by resting and post-NTG resting imaging, respectively). From initial to final imaging, the mean defect areas were significantly decreased(P<0. 05 ). After NTG, the mean defect sizes were significantly decreased(P<0. 01) and the mean counts of the defect region were significantly increased(P<0.05 ) in both the initial and final imagings. Conclusion: 99mTc-MIBI SPECT is auseful method to demonstrate the size of myocardial damage and the administration of NTG before resting MIBI injection may improve the detection of residual viability in hypoperfused regions.