KINETICS OF IODINE-123-BMIPP IN PATIENTS WITH PRIOR MYOCARDIAL-INFARCTION - ASSESSMENT WITH DYNAMIC REST AND STRESS IMAGES COMPARED WITH STRESS TL-201 SPECT

Myocardial kinetics of I-123-labeled 15-(p-iodophenyl)3R, S-methylpent adecanoic acid (BMIPP) were evaluated with dynamic SPECT, and stress a nd rest BMIPP images were directly compared in conjunction with stress (TI)-T-201. Methods: We studied 26 patients with prior myocardial; in farction. Two minutes after injection of BMIPP, dynamic data acquisiti on with a three-headed SPECT was started and continued for 12 min. Con ventional SPECT images were obtained at 20 min and 3 hr after injectio n. On a separate day, exercise, stress (TI)-T-201 SPECT was performed at 10 min and 3 hr after injection. Exercise stress-BMIPP imaging was performed in 15 of the patients, and static SPECT images were obtained . Results: With dynamic SPECT, early clearance of BMIPP from the myoca rdium was observed in the segments with reversible (TI)-T-201 defects, suggesting enhanced contribution of backdiffusion from BMIPP. In myoc ardial segments with reversible (TI)-T-201 defects, 20-min BMIPP image s showed a higher frequency of reduced uptake when compared to 3-hr (T I)-T-201 (90/163) imaging. Conclusion: With BMIPP dynamic SPECT, an en hanced contribution of backdiffusion in the early phase from ischemic myocardium was suggested. When exercise stress BMIPP images were obtai ned, a more severe defect was observed than on rest BMIPP and stress ( TI)-T-201 imaging, possibly due to decreased coronary blood flow and i mpaired fatty acid uptake induced by ischemia during exercise.