Okada R D, Nguyen K N, Lauinger M, Allton I L, Johnson G
William K Warren Medical Research Institute of the University of Oklahoma Health Sciences Center, Tulsa, OK 74136, USA.
Am Heart J. 1996 Jul;132(1 Pt 1):108-15. doi: 10.1016/s0002-8703(96)90397-x.
Technetium 99m-Q12 is a new cationic myocardial perfusion imaging agent that produces excellent images in human beings. The purpose of this study was to examine the separate effects of hypoxia and low flow on myocardial clearance kinetics. After a 1 mCi bolus injection, myocardial 99mTc-Q12 clearance was monitored for 1 hour by using an Nal detector in 24 isolated perfused rat hearts. In 6 control hearts, flow was 12 ml/min, and oxygenation was normal. In 6 hypoxic hearts, flow was normal, but oxygenation was reduced (<5% 02). In 6 low-flow hearts, flow was 3 ml/min, and oxygenation was normal. In 6 very low flow hearts, flow was 1 ml/min, and oxygenation was normal. 99mTc-Q12 myocardial clearance was biphasic in all four groups, consisting of a rapid early phase and a second slow phase that began after 10 minutes. Myocardial retention between 1 and 10 minutes was 56.8% +/- 1.8% for control, 49.2% +/- 2.2% (p < 0.05 compared with control) for hypoxic, 56.8% +/- 2.6% (p = NS compared with control) for low flow (3 ml/min), and 63.7% +/- 2.1 % (p < 0.05 compared with control) for very low flow hearts (1 ml/min). Myocardial retention between 10 and 60 minutes was 90.5% +/- 0.2% for control, 90.2% +/- 1.6% for hypoxic, 90.0% +/- 0.8% for low-flow hearts (3 ml/min), and 87.6% +/- 0.3% (p < 0.05 compared with other groups) for very low flow hearts (1 ml/min). In conclusion, 99mTc-012 demonstrates biphasic clearance from normal, hypoxic, low-flow, and very low flow ischemic myocardium. Early-phase myocardial retention is decreased by hypoxia and increased by very low flow.
锝99m - Q12是一种新型阳离子心肌灌注显像剂，能在人体中产生优质图像。本研究的目的是研究缺氧和低灌注对心肌清除动力学的单独影响。在24个离体灌注大鼠心脏中，经静脉团注1毫居里后，使用碘化钠探测器监测心肌对99mTc - Q12的清除情况，持续1小时。6个对照心脏，灌注流量为12毫升/分钟，氧合正常。6个缺氧心脏，灌注流量正常，但氧合降低（氧含量<5%）。6个低灌注心脏，灌注流量为3毫升/分钟，氧合正常。6个极低灌注心脏，灌注流量为1毫升/分钟，氧合正常。四组中99mTc - Q12心肌清除均呈双相，包括快速的早期相和10分钟后开始的第二缓慢相。1至10分钟心肌滞留率，对照组为56.8%±1.8%，缺氧组为49.2%±2.2%（与对照组相比，p<0.05），低灌注（3毫升/分钟）组为56.8%±2.6%（与对照组相比，p =无显著差异），极低灌注（1毫升/分钟）组为63.7%±2.1%（与对照组相比，p<0.05）。10至60分钟心肌滞留率，对照组为90.5%±0.2%，缺氧组为90.2%±1.6%，低灌注（3毫升/分钟）组为90.0%±0.8%，极低灌注（1毫升/分钟）组为87.6%±0.3%（与其他组相比，p<0.05）。总之，99mTc - Q12在正常、缺氧、低灌注和极低灌注缺血心肌中的清除呈双相。缺氧会降低早期心肌滞留率，极低灌注会增加早期心肌滞留率。
