Imaging Myocardial Scans and Wall Motion Studies Using Tc-99m Pyrophosphate in Suspected Acute Myocardial Infarctions

Two different radionuclide procedures were performed on 53 patients to validate a clinical diagnosis of acute myocardial infarction (AMI). A bolus of Tc-99m pyrophosphate was in-jected, and on the first pass of this bolus through the heart, left ventricular wall motion studies were performed. This was fol-lowed by myocardial scintigraphy. A second wall motion study in another projection was performed after a second bolus in-jection. Data suggest that the combination of the scintigram and wall motion study was significantly valuable in determining the patients ' diagnoses. Patients with acute myocardial infarction (AMI) continue to provide a diagnostic challenge to the clinician-even with present diagnostic methods, an AMI often remains difficult to confirm (1,2). In our department, first pass wall motion studies were carried out on all patients referred for myocardial scintigraphy. Our objective was to determine the value of wall motion studies in this patient population. Materials and Methods Fifty-three patients with suspected recent AMI were brought to our nuclear medicine department under ap-propriate supervision. Their ages ranged from 46 to 78 years and they included 42 men and 11 women. The wall motion studies were performed using a Cordis-Baird computerized multicrystal camera, System Seventy-Seven ® (Cordis-Baird, Bedford, MA), with the 1-in.lead collimator. Each patient was positioned under the de-tector in a 20 ° left anterior oblique (LAO) projection and 15 mCi ofTc-99m pyrophosphate was injected as a bolus, followed by 20 ml of saline. Precordial activity was re-corded as I,000 50-msec frames. Myocardial scintigrams to an information densit