Detection of coronary artery disease with rapid serial rescanning with potassium-43 at rest

To improve the sensitivity and accuracy of the detection of coronary artery disease with potassium-43 imaging at rest, a rapid serial scanning technique was developed to detect appearance time and sequence of myocardial isotope accumulation. The group of 85 patients included normal subjects and patients with angina pectoris, myocardial infarction and miscellaneous nonischemic heart diseases. Each patient also underwent coronary angiography and left ventriculography and the results were compared with the results of scanning. An angiographically demonstrable obstruction of 50 percent or greater luminal diameter in a coronary artery was found in 95 percent of the patients whose first serial myocardial scan at rest, accomplished 4.5 minutes after isotope administration, showed delayed regional appearance or abnormal sequence of accumulation of radioactivity by the end of the second scan. Eighty-five percent of individual lesions in a major coronary artery identified by scanning were found at the same site on angiography. Ventricular aneurysms were demonstrated as positive images during the first serial scan, although later scans showed no myocardial activity. Collateral circulation was demonstrable on serial scanning and, when angiographic evidence of such circulation was available, the recipient arterial bed was always correctly identified. In 32 patients who underwent myocardial imaging at rest and after graded exercise testing, the images at rest correlated better with the angiographic data. In conclusion, rapid serial scanning at rest detected coronary arterial lesions of 50 percent or greater, collateral circulation and, often, ventricular aneurysms as positive images.