This study test whether sublingual administration of nitroglycerin (NTG) could improve the capability of99mTc-MIBI to detect reversibility in exercise-induced perfusion defects and to compare it with the201TI stress-redistribution-reinjection protocol. Twenty-one patients with previous myocardial infarction were submitted to exercise,
rest and NTG rest99mTc-MIBI imaging (3-day protocol). The patients also underwent exercise, redistribution and reinjection201Tl myocardial scintigraphy. A total of 273 myocardial segments were analyzed: 76 (28%) had irreversible defects on stress-rest99mTc-MIBI, 60 (79%) appeared as fixed defects and 16 (21%) were reversible on NTG rest99mTc-MIBI. Of the 78 myocardial segments with irreversible defects on standard stress-redistribution thallium cardiac imaging,
63 (81%) did not change and 15 (19%) demonstrated enhanced uptake of thallium after reinjection. Data show that rest NTG99mTc-MIBI study improves the detection of reversible myocardium versus standard exercise/rest99mTc-MIBI and achieve similar results than201Tl reinjection protocol.