Evaluation of coronary artery disease using locally prepared myocardial perfusion agent 99mTc-MIBI

Technetium (99mTc) labelled isonitrile complexes are recently introduced agents for imaging myocardial perfusion and viability. This study presents the first clinical experience with a locally prepared agent 99mTc methoxy iso butyl isonitrile (MIBI). Sixteen randomly selected cases (M:F 14:2, mean age 48 years) were included; clinically 4 patients were asymptomatic, 6 had history of MI while remaining 6 had angina with no previous incidence of MI. Separate injections were given for rest and stress studies either on the same day (9 cases) or on separate days (7 cases). All patients were stressed according to the Modified Bruce Protocol and 99mTc MIBI was injected at peak stress. Early blood pool and delayed static images showed reasonably good localization of MIBI in the viable myocardium and image quality was also comparable to what has been reported in literature. Scans were negative for any perfusion abnormality in 6 cases, positive for single vessel disease in 6 and for two vessels disease in 4 patients. We conclude that the locally prepared 99mTc MIBI has optimal sensitivity and pharmacokinetic properties for myocardial imaging and detection of CAD. Moreover the local preparation would also entail considerable foreign exchange saving.