Canby R C, Silber S, Pohost G M
Department of Medicine, University of Alabama, Birmingham 35294.
Circulation. 1990 Jan;81(1):289-96. doi: 10.1161/01.cir.81.1.289.
Myocardial imaging with thallium 201 has proven to be an important clinical procedure to assess the severity of the myocardial ischemic insult. Uptake of 201Tl is related to perfusion to and extraction by intact myocardium. Recently, a newer group of agents based on 99mTc alkyl isonitriles has been developed and appears promising for myocardial imaging. Although the distribution of this new agent has been shown to be related to myocardial perfusion, its dependence on myocardial integrity has not been established. This study compared the distribution of 99mTc-2-methoxy-isobutyl-isonitrile (99mTc-MIBI) with that of 201Tl in a clinically relevant canine model of ischemic insult. Fifteen adult dogs underwent 2 hours of occlusion by left anterior descending coronary artery ligation followed by reperfusion. In one group of dogs, 201Tl and 99mTc-MIBI were administered 5 minutes before 35 minutes of reflow (group 1, n = 5). In the other animals, the agents were given 5 minutes after onset of reflow, and dogs were killed after 10 (group 2, n = 5) and 35 minutes of reperfusion (group 3, n = 5). 99mTc-MIBI activity was significantly correlated with 201Tl activity (r = 0.91, 0.77, and 0.92, for groups 1, 2, and 3, respectively). Both 201Tl and 99mTc-MIBI activities were correlated similarly with blood flow in all models. In groups 1 and 2, 201Tl and 99mTc-MIBI activities correlated directly with microsphere-determined blood flow, whereas in group 3, they correlated inversely. The present study shows that in these models of myocardial ischemic insult, 99mTc-MIBI distribution is closely related to that of 201Tl.
用铊201进行心肌显像是影已被证明是评估心肌缺血损伤严重程度的一项重要临床检查。铊201的摄取与完整心肌的灌注及摄取有关。最近，已开发出一组基于锝99m烷基异腈的新型药物，在心肌显像方面似乎很有前景。尽管已证明这种新药的分布与心肌灌注有关，但其对心肌完整性的依赖性尚未确定。本研究在一个与临床相关的犬类缺血损伤模型中，比较了锝99m - 2 - 甲氧基 - 异丁基 - 异腈（锝99m - MIBI）和铊201的分布情况。15只成年犬通过左前降支冠状动脉结扎进行2小时的闭塞，随后再灌注。在一组犬中，在再灌注35分钟前5分钟给予铊201和锝99m - MIBI（第1组，n = 5）。在其他动物中，在再灌注开始后5分钟给予这些药物，在再灌注10分钟（第2组，n = 5）和35分钟（第3组，n = 5）后处死犬。锝99m - MIBI活性与铊201活性显著相关（第1、2和3组的r分别为0.91、0.77和0.92）。在所有模型中，铊201和锝99m - MIBI活性与血流的相关性相似。在第1组和第2组中，铊201和锝99m - MIBI活性与微球测定的血流直接相关，而在第3组中，它们呈负相关。本研究表明，在这些心肌缺血损伤模型中，锝99m - MIBI的分布与铊201密切相关。
