Myocardial uptake of 99mTc-tetrofosmin, sestamibi, and 201Tl in a model of acute coronary reperfusion

Background 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. Methods and Results 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%) ...