Takahashi N, Reinhardt C P, Marcel R, Leppo J A
Department of Nuclear Medicine, University of Massachusetts Medical Center, Worcester 01655-0243, USA.
Circulation. 1996 Nov 15;94(10):2605-13. doi: 10.1161/01.cir.94.10.2605.
To investigate whether tetrofosmin uptake is affected by myocardial viability as has been noted for 201Tl and sestamibi, we analyzed the initial and delayed distribution patterns of tetrofosmin in a rat coronary artery occlusion-reperfusion model.
Animals were intubated and ventilated, and their arterial pressures were monitored. A left thoracotomy was performed. After 1-hour occlusion and 1-hour reperfusion of a major branch of the circumflex artery, 201Tl and either tetrofosmin or sestamibi were injected intravenously. Radiolabeled microspheres were used to document the area at risk and reperfusion. Five minutes or 1 hour after administration of the diffusible tracers, the animals were killed. Tracer distribution was determined by use of segmental tissue analysis, and tissue viability was determined by use of histochemical staining. Both the initial and delayed retention of tetrofosmin were sensitive to myocardial viability, as shown by significantly lower uptake (30 +/- 14%) and retention (24 +/- 12%) of tetrofosmin in the nonviable segments compared with the viable segments. In addition, the initial myocardial distribution of tetrofosmin was similar to that noted for 201Tl, but after 1 hour of tracer circulation, the tetrofosmin tissue distribution appeared unchanged compared with the initial regional blood flow distribution. This is in direct contrast to our present observations of significant 201Tl redistribution and some changes in sestamibi distribution as well.
The clinical implication of these observations suggests that initial and delayed imaging after tetrofosmin administration would reflect both the initial regional blood flow pattern and myocardial viability.
为了研究替曲膦摄取是否像铊 - 201和 sestamibi那样受心肌存活情况的影响，我们在大鼠冠状动脉闭塞 - 再灌注模型中分析了替曲膦的初始和延迟分布模式。
动物进行插管和通气，并监测其动脉压。实施左胸廓切开术。在左旋支动脉的一个主要分支闭塞1小时和再灌注1小时后，静脉注射铊 - 201以及替曲膦或 sestamibi。使用放射性微球记录危险区域和再灌注情况。在给予可扩散示踪剂5分钟或1小时后，处死动物。通过节段性组织分析确定示踪剂分布，通过组织化学染色确定组织存活情况。替曲膦的初始和延迟滞留均对心肌存活情况敏感，与存活节段相比，在无存活心肌的节段中替曲膦摄取（30±14%）和滞留（24±12%）显著降低。此外，替曲膦的初始心肌分布与铊 - 201相似，但在示踪剂循环1小时后，与初始区域血流分布相比，替曲膦的组织分布似乎未改变。这与我们目前观察到的铊 - 201的显著再分布以及 sestamibi分布的一些变化形成直接对比。
这些观察结果的临床意义表明，替曲膦给药后的初始和延迟成像将反映初始区域血流模式和心肌存活情况。
