Detection of myocardial viability using redistribution thallium-201 imaging in a stress Tc-99(m)-tetrofosmin/rest thallium-201 dual-isotope protocol

This study investigated the utility of optional thallium-201 (Tl-201) imagi ng for detecting myocardial viability in the stress Tc-99(m)-tetrofosmin/re st Tl-201 dual-isotope protocol. Seventy-nine patients with old myocardial infarction and 25 patients with acute myocardial infarction underwent acqui sition of three consecutive Tl-201 images (early, intermediate and delayed) using the dual-isotope protocol. A polar map was created and defect scores (extent and severity) were determined by comparison with normal control da ta. Fluorodeoxyglucose positron emission tomography was also performed in 1 6 patients with old myocardial infarction. In patients with old infarction, the severity score decreased significantly from the early to the intermedi ate images, and decreased further on the delayed images. In patients with a cute infarction, the score increased from the early to the intermediate ima ges, but not on the delayed images. Regional uptake on the delayed images s howed a better correlation with the fluorodeoxyglucose images than that on the early images. Redistribution on the delayed images was exclusively obse rved in the myocardial segments with less uptake than that estimated by flu orodeoxyglucose. In conclusion, addition of delayed Tl-201 imaging to the d ual-isotope protocol could improve the sensitivity for detecting myocardial viability. ((C) 2001 Lippincott Williams & Wilkins).