Myocardial reversibility detection. Rest NTG Tc-99m-MIBI versus Tl-201 reinjection. Preliminary results

This study test whether sublingual administration of nitroglycerin (NTG) co uld improve the capability of Tc-99m-MIBI to detect reversibility in exerci se-induced perfusion defects and to compare it with the Tl-201 stress-redis tribution-reinjection protocol. Twenty-one patients with previous myocardia l infarction were submitted to exercise, rest and NTG rest Tc-99m-MIBI imag ing (3-day protocol). The patients also underwent exercise, redistribution and reinjection Tl-201 myocardial scintigraphy. A total of 273 myocardial s egments were analyzed: 76 (28%) had irreversible defects on stress-rest (TC )-T-99m-MIBI, 60 (79%) appeared as fixed defects and 16 (21%) were reversib le on NTG rest Tc-99m-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 aft er reinjection. Data show that rest NTG Tc-99m-MIBI study improves the dete ction of reversible myocardium versus standard exercise/rest Tc-99m-MIBI an d achieve similar results than Tl-201 reinjection protocol.