IMPAIRED FATTY-ACID UPTAKE IN ISCHEMIC BUT VIABLE MYOCARDIUM IDENTIFIED BY TL-201 REINJECTION

Iodine 123-labeled 15-iodophenyl-3-methyl-pentadecanoic acid (BMIPP) h as been proposed as a potential myocardial fatty acid probe. We studie d BMIPP uptake in ischemic myocardium identified by thallium reinjecti on. Fifty-five patients with coronary artery disease who had persisten t defects on standard exercise-redistribution thallium imaging were in vestigated. Patients underwent exercise-redistribution-reinjection tha llium and resting BMIPP imaging. BMIPP uptake less than that seen with thallium on reinjection imaging was observed in 105 (82%) of 128 myoc ardial segments with new fill-in after thallium reinjection and 87 (37 %) of 238 segments with reversible thallium defects. In contrast, only 32 (19%) of 166 segments with no fill-in showed discordantly decrease d BMIPP uptake. Quantitative analysis showed reduction in BMIPP activi ty compared with differential uptake of thallium, an index of resting myocardial perfusion, especially in the area of fill-in (53.5% +/- 15. 0% vs 76.0% +/- 12.1% of peak; p < 0.01). These observations are consi stent with impaired fatty acid uptake in ischemic myocardium, particul arly in the area of fill-in after thallium reinjection.