Evaluation of myocardial viability using sequential dual-isotope single photon emission tomography imaging with rest TI-201/stress Tc-99m tetrofosmin in the prediction of wall motion recovery after revascularization.

Abstract

In patients with coronary artery disease (CAD), differentiation between severely ischemic but potentially viable myocardium and irreversibly infarcted tissue is clinically important, particularly when revascularization procedures are considered. Although thallium (TI) cardiac imaging has been shown to be a good tool for investigating myocardial viability in CAD, this tracer shows physical limitations, such as a low photon energy and long half-life. We assessed the results of a rest TI-201/stress Tc-99m tetrofosmin protocol in subjects with prior anterior myocardial infarction. All of the patients had an akinetic or dyskinetic area and more than 75% stenosis in the left anterior descending artery. All of the patients underwent revascularization after the examination. We evaluated the improvement in wall motion after revascularization using the centerline method with contrast left ventricular angiography. Fourteen patients showed reversible defects with the rest TI-201/stress Tc-99m tetrofosmin protocol or in additional TI-201 24 h redistribution images. All 14 patients showed a significant improvement in wall motion after revascularization. Dual-isotope rest TI-201/stress Tc-99m tetrofosmin single photon emission tomography data, acquired separately, may give fast and complete information about myocardial perfusion during stress and at rest, and on about myocardial viability.