Assessment of regional myocardial perfusion by positron emission tomography after intracoronary administration of Gallium-68 labeled albumin microspheres.

Positron emission computed tomography (ECT) of the normal and ischemic canine heart was undertaken in eight anesthetized dogs after the intracoronary administration of 68gallium labeled human serum albumin microspheres (SAM). Bolus doses of 200 muCi of 68Ga-SAM were injected into the left anterior descending (LAD) and left circumflex coronary arteries of four normal dogs and four dogs undergoing LAD ligation. Positron imaging of 68Ga-SAM distribution was performed with a multicrystal positron camera and computer reconstruction. In normal dogs, five to six axial transverse section images of the heart demonstrated the transmural distribution of 68Ga-SAM in an annular pattern around the left ventricular cavity. In dogs with LAD ligation, perfusion defects in the anterolateral wall and septum were observed in tomographic cuts through ischemic areas. In conclusion, these studies demonstrate the feasibility of positron ECT imaging of the heart after intracoronary administration of 68Ga-SAM.