Cesium-129 Myocardial Scintigraphy to Detect Myocardial Infarction

Cesium-129 is concentrated in the myocardium after intravenous administration permitting myocardial imaging. The dosage used was 2-2.5 mCi in dogs and 3-4 mCi in patients. Four or more views with 200,000 counts per view were obtained 30 to 90 minutes after administration. Control images were obtained in 30 dogs. In two dogs anatomic landmarks were obtained using technetium-99m markers. In 24 dogs, either the anterior descending or circumflex coronary artery was ligated. An area of absent uptake of 129 Cs was seen involving the anterior wall and apex or the inferior-posterior wall, respectively. At postmortem this represented a myocardial infarction (MI) averaging 4x5 cm. Smaller MI (2x3 cm) at postmortem were seen as defects of the anterior wall. Evolution of an acute MI was followed in four dogs. The defect appeared at one hour and gradually increased on serial images. Fifty patients were studied. Each of 20 patients without evidence of MI had the normal horseshoe or doughnut appearance of the left ventricle surrounding the interventricular cavity. Each of 15 patients with acute MI and 10 of the 13 patients with an old MI had a defect on the myocardial image. The three patients without defects had infarction of the inferior wall. One of two patients with coronary insufficiency had a defect. These studies show that good quality myocardial images were obtained with 129 Cs and strongly suggest its potential usefulness in quantification of an acute MI.