Johnson G, Nguyen K N, Liu Z, Gao P, Pasqualini R, Okada R D
William K. Warren Medical Research Institute of the University of Oklahoma Health Sciences Center and Cardiology of Tulsa 74136, USA.
J Nucl Cardiol. 1997 May-Jun;4(3):217-25. doi: 10.1016/s1071-3581(97)90082-9.
(99m)Tc-labeled (bis(N-ethoxy, N-ethyl dithiocarbamato) nitrido technetium(V)) ([99m]TcN-NOET) is a new lipophilic, neutral-charge cardiac perfusion imaging agent that demonstrates apparent redistribution in animal models and humans. The purpose of this study was to determine whether the kinetics of (99m)TcN-NOET are suitable for the detection of resting ischemia.
Microspheres were injected at baseline and simultaneously with (99m)TcN-NOET after a 90% reduction in resting flow in the left circumflex coronary artery in six open-chest canine experiments. The relationship of flow and activity early after injection was determined in one experiment by termination at 10 minutes. The flow ratio (left circumflex/left anterior descending coronary artery) after stenosis fell significantly (0.87 +/- 0.04 vs 0.46 +/- 0.04; p < 0.05). The end-tissue (99m)Tc ratio (0.78 +/- 0.05) was significantly higher than the flow ratio at injection (0.46 +/- 0.04; p < 0.05), indicating substantial redistribution. In vivo imaging was conducted during 2 hours in five experiments, followed by ex vivo imaging. Myocardial clearance from 10 minutes onward was biphasic in left anterior descending and monophasic in left circumflex coronary arteries. Myocardial clearance from 10 to 60 minutes was delayed in left circumflex (35.5% +/- 8.1%) versus left anterior descending coronary arteries (49.2% +/- 8.6%; p < 0.05). No significant difference was observed from 60- to 120-minute clearance. Five of five experiments demonstrated initial defects and complete fill-in at 90 to 120 minutes by qualitative assessment. Quantitation of ex vivo images confirmed significant redistribution.
Resting ischemia caused by moderate to severe stenosis can be detected on scans with (99m)TcN-NOET. Redistribution was near complete in this model by 90 to 120 minutes. (99m)TcN-NOET is a promising new agent for the detection of coronary artery disease in viable myocardium and warrants further investigation.
锝-99m标记的（双（N-乙氧基，N-乙基二硫代氨基甲酰基）氮合锝（Ⅴ））（[99m]TcN-NOET）是一种新型亲脂性、中性电荷的心脏灌注显像剂，在动物模型和人体中显示出明显的再分布。本研究的目的是确定[99m]TcN-NOET的动力学是否适用于检测静息性心肌缺血。
在6只开胸犬实验中，于左旋冠状动脉静息血流减少90%后，在基线时及同时注射[99m]TcN-NOET时注入微球。在一项实验中，通过在10分钟时终止实验来确定注射后早期血流与活性的关系。狭窄后血流比值（左旋/左前降支冠状动脉）显著下降（0.87±0.04对0.46±0.04；p<0.05）。终末组织[99m]Tc比值（0.78±0.05）显著高于注射时的血流比值（0.46±0.04；p<0.05），表明存在大量再分布。在5项实验中于2小时内进行了体内显像，随后进行了体外显像。左前降支冠状动脉10分钟后心肌清除呈双相性，左旋冠状动脉呈单相性。左旋冠状动脉10至60分钟的心肌清除延迟（35.5%±8.1%），而左前降支冠状动脉为49.2%±8.6%（p<0.05）。60至120分钟的清除未见显著差异。5项实验中有5项通过定性评估显示初始缺损并在90至120分钟时完全填充。体外图像定量证实了显著的再分布。
中重度狭窄引起的静息性心肌缺血可通过[99m]TcN-NOET扫描检测到。在该模型中，90至120分钟时再分布接近完全。[99m]TcN-NOET是检测存活心肌中冠状动脉疾病的一种有前景的新型显像剂，值得进一步研究。
