MYOCARDIAL PERFUSION WITH RUBIDIUM-82 .2. EFFECTS OF METABOLIC AND PHARMACOLOGIC INTERVENTIONS

Abstract

In order to validate a new method for quantifying coronary blood flow, a bolus of 82Rb was injected i.v. into 28 open-chested dogs under a wide range of flow and physiologic conditions, using .beta. probes to monitor myocardial radioactivity. Extraction fraction and perfusion were measured using a functional model that separates the data into the free and trapped myocardial Rb. Extraction and uptake of Rb were lower during acidosis than during alkalosis and were unchanged by glucose-insulin, digoxin or propranolol. Myocardial flow, as indicated by Rb, correlated linearly with simultaneous measurements of flow by microspheres in the same sample volume over a wide range of flow (r = 0.97, n = 106, range 0.02-7.76 ml/min per g). Regional myocardial blood flow can be accurately determined using generator-produced 82Rb. Studies using current state-of-the-art, fast positron-emission tomographic cameras are required to determine the utility of this approach in man.