Redistribution of 99mTc-sestamibi and 201Tl in the presence of a severe coronary artery stenosis.
Redistribution of 99mTc-sestamibi and 201Tl in the presence of a severe coronary artery stenosis.
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存在严重冠状动脉狭窄时 99mTc-sestamibi 和 201Tl 的重新分布。
DOI：
10.1161/01.cir.89.5.2332
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发表时间：
1994
期刊：
影响因子：
37.8
通讯作者：
Beller,GA
中科院分区：
文献类型：
--
作者：
Sinusas,AJ;Bergin,JD;Edwards,NC;Watson,DD;Ruiz,M;Makuch,RW;Smith,WH;Beller,GA
背景 99mTc 标记的甲氧基异丁基异腈 (99mTc-sestamibi) 是一种心肌灌注剂，可从心肌中缓慢清除。本研究评估了存在低流量缺血时 99mTc-sestamibi 和 201Tl 的早期和晚期心肌分布，以确定 99mTc-sestamibi 是否表现出休息“重新分布”。 方法和结果 通过部分闭塞左冠状动脉前降支，在 18 只麻醉的开胸狗中产生低流量缺血。在持续低流量缺血期间，给狗静脉注射 99mTc-sestamibi、301Tl 和放射性标记微球。注射后20分钟（第1组，10只狗）或2.5小时（第2组，8只狗）切除心脏进行伽马井计数，以评估这些放射性示踪剂相对于微球流量的早期和晚期心肌分布。 99mTc-sestamibi 和 201Tl 的早期心肌分布具有可比性，并且与血流不足相关（第 1 组）。我们观察到第 1 组和第 2 组狗的心肌 201Tl (P = .005) 和 99mTc-sestamibi (P < .0001) 活动相对于流量存在显着差异，表明两种示踪剂存在一定的重新分布。死后用伽玛相机对心肌切片进行成像，并对 99mTc-sestamibi 缺陷强度进行量化。尸检图像上的早期相对 99mTc-sestamibi 缺陷强度与血流缺陷（第 1 组）之间存在极好的相关性 (r = .97)。在第 2 组狗中，相关性良好 (r = .87)，但 99mTc-sestamibi 缺陷不如血流缺陷严重，再次表明重新分布。 结论 注射后早期 99mTc-sestamibi 和 201Tl 的心肌分布具有可比性且与血流成正比。在持续低流量的条件下，通过伽马井计数和心肌切片的高分辨率死后成像验证了可检测到的 99mTc-sestamibi 的剩余“重新分布”。这种程度的 99mTc-sestamibi 剩余重新分布是否可以通过系列临床成像检测到仍不确定。然而，这些数据表明，在存在严重狭窄的情况下评估心肌活力时，应在静息注射 99mTc-sestamibi 后延迟成像。
BACKGROUND99mTc-labeled methoxyisobutyl isonitrile (99mTc-sestamibi) is a myocardial perfusion agent that clears slowly from the myocardium. This study evaluates the early and late myocardial distributions of 99mTc-sestamibi and 201Tl in the presence of low-flow ischemia to determine whether 99mTc-sestamibi demonstrates rest "redistribution."METHODS AND RESULTSLow-flow ischemia was produced in 18 anesthetized, open-chest dogs by partial occlusion of the left anterior descending coronary artery. Dogs were injected intravenously with 99mTc-sestamibi, 301Tl, and radiolabeled microspheres during sustained low-flow ischemia. The hearts were excised either 20 minutes (group 1, 10 dogs) or 2.5 hours (group 2, 8 dogs) after injection for gamma well counting to evaluate the early and late myocardial distributions of these radiotracers, relative to microsphere flow. The early myocardial distributions of 99mTc-sestamibi and 201Tl were comparable and correlated with the flow deficit (group 1). We observed a significant difference in myocardial 201Tl (P = .005) and 99mTc-sestamibi (P < .0001) activities between groups 1 and 2 dogs relative to flow, suggesting some redistribution of both tracers. Myocardial slices were imaged postmortem with a gamma camera, and 99mTc-sestamibi defect intensity was quantified. There was excellent correlation (r = .97) between the early relative 99mTc-sestamibi defect intensity on postmortem images and the flow deficit (group 1). Among group 2 dogs, the correlation was good (r = .87), but the 99mTc-sestamibi defect was less severe than the flow deficit, again suggesting redistribution.CONCLUSIONSThe myocardial distributions of 99mTc-sestamibi and 201Tl early after injection are comparable and proportional to flow. Under conditions of sustained low flow, there was detectable rest "redistribution" of 99mTc-sestamibi verified by both gamma well counting and high-resolution postmortem imaging of myocardial slices. Whether this degree of 99mTc-sestamibi rest redistribution will be detectable by serial clinical imaging remains uncertain. Nevertheless, these data suggest that imaging should be delayed after the resting injection of 99mTc-sestamibi when assessing myocardial viability in the presence of a critical stenosis.