Noninvasive evaluation of regional myocardial perfusion with positron emission computed tomography

Positron emission computed tomography (PET) offers regional measurement of physiological and biochemical processes in vivo. We have constructed a whole-body multislice PET scanner, which provides 7 tomographic images at 16 mm intervals simultaneously. The high sensitivity with good spatial resolution of this system permits dynamic studies of the heart. PET scan of the heart was performed following intravenous bolus injection of 13N labeled ammonia. Serial dynamic images in normal cases showed early accumulation of tracer in the myocardium and rapid clearance from the cardiac blood pool. Delayed clearance from the blood and prolonged retention in the dorsal part of the lungs were observed in cases with myocardial infarction. A perfusion defect was clearly visualized in myocardial infarction except for infarction of the inferior wall. Transient ischemia was also visualized with exercise loading. Thus, PET with 13N ammonia is a valuable diagnostic tool for the evaluation of regional myocardial perfusion in coronary artery disease.