Radioactive particle imaging of coronary blood flow distribution.

The intracoronary injection of radionuclide-labeled macroaggregated albumin particles has been shown to be safe and to provide excellent myocardial imaging. When performed in the resting state, it is more sensitive than either the ECG or ventriculogram in identifying areas of scarring and fibrosis due to previous myocardial infarction. Combined with contrast induced coronary hyperemia, intracoronary MAA particles are useful in identifying stenoses of moderate severity that do not alter resting coronary blood flow. Particle studies are likely more sensitive than the rest-exercise 210T1 myocardial scan in identifying patients with significant coronary artery disease. Resting perfusion abnormalities are more closely related to improved or unimproved left ventricular function after surgery than are the ECG or resting left ventriculogram. While the long-range clinical utility of the particle technique is uncertain, its most useful application currently is identification of significant stenoses undetected by 201T1 and of questionable significance by arteriography.