Using Indium-111-labeled Autologous Platelets

The feasibility of imaging the inflammatory response to acute transmural myocardial infarction in man using biologically active indium-111 ("'ln)-labeled autologous leukocytes was assessed in 36 patients. Indium-111 leukocytes (approximately 500 ,tCi) were injected i.v. 18-112 hours after the onset of chest pain. Cardiac imaging was performed 24 hours later with a mobile gamma camera. Twenty-one patients had positive images and 15 had negative images. The percent of positive images increased as the interval between infarction and "'In-leukocyte injection shortened; all patients injected within 24 hours of infarction had positive images. Patients with positive images were injected with "'In leukocytes earlier after infarction (mean ± SEM, 43 ± 4 vs 63 ± 7 hours; p < 0.05) and were younger (53 ± 2 vs 65 ± 3 years; p < 0.05) than those with negative images. Several other parameters that could possibly have affected the imaging results were examined and were not significantly different in patients with positive and negative images. These included peak serum creatine kinase, location of infarction, incidence of pericarditis, use of antiinflammatory drugs (aspirin and indomethacin) or membrane-active antiarrhythmic drugs (lidocaine and procainamide), peripheral leukocyte count and cell labeling efficiency. The function of the labeled cells was similar in patients with positive and negative images. Six patients with acute infarction serving as controls and given free "`In oxine and six patients with stable coronary artery disease given "`In leukocytes all had negative cardiac images.