Prognostic value of 1-day stress/rest electrocardiogram-gated single- photon emission computed tomography using Tc-99m-labeled methoxy-isobutyl isonitrile

Abstract

To evaluate the prognostic value of the simultaneous assessment of perfusion and left ventricular wall motion, exercise non-gated/rest electrocardiogram (ECG)-gated 99mTc methoxy-isobutyl isonitrile (MIBI) single-photon emission computed tomography (SPECT) was performed in 182 patients suspected of having coronary artery disease. After injection of 250 MBq of 99mTc-MIBI at peak exercise, stress perfusion images were classified into 3 groups: normal, equivocal, and abnormal. Normal subjects completed the 1-day protocol but not the resting study, whereas patients with abnormal or equivocal perfusion images underwent ECG-gated SPECT study with injection of 750 MBq of 99mTc-MIBI 3 h later. Patients with normal perfusion during this protocol had a benign prognosis. Only 4 soft events occurred in the normal group (4.8%). In contrast, patients with both myocardial infarction and abnormal wall motion at rest experienced more cardiac events (7 cardiac events including 1 cardiac death among a total of 45 patients; 15.6%, p<0.05 compared with normal subjects). In addition, ischemic patients also experienced more cardiac events (7 events including 2 cardiac deaths among a total of 25 subjects; 28.0%, p<0.01 compared with normal patients). Our data suggest that the simultaneous assessment of perfusion and wall motion by stress/rest ECG-gated 99mTc-MIBI SPECT is a reliable indicator of prognosis in patients suspected of having coronary artery disease.