COMPARISON OF TC-99(M)-PYROPHOSPHATE, TL-201 PERFUSION, I-123 LABELEDMETHYL-BRANCHED FATTY-ACID AND SYMPATHETIC IMAGING IN ACUTE CORONARY SYNDROME

Among a group of patients (n=15) with acute coronary syndrome, the res ults of using two new myocardial radiopharmaceuticals - I-123-labelled 15-(p-iodo-phenyl)-3,R,S-methylpentadecanoic acid (BMIPP) and I-123-m eta-iodobenzyl guanidine (MIBG) - were compared with dual Tl-201/Tc-99 (m)-pyrophosphate (Tl-PYP) imaging using single photon emission tomogr aphy (SPET). Defect scores were evaluated on a segment-by-segment basi s for a total of 270 segments. For the Tl-201, BMIPP, and early and de layed MIBG studies, the mean (+/- S.D.) sums of defect scores were 9 /- 8, 18 +/- 9, 22 +/- 12 and 29 +/- 9, respectively, revealing signif icantly higher scores for BMIPP and MIBG than Tl-201 (P<0.005). This w as the case irrespective of various functional conditions, such as suc cessful recanalization, failure of coronary angioplasty or restenosis. The culprit coronary artery was best identified using BMIPP, while MI BG SPET showed the most extensive defects. Normal perfusion with decre ased BMIPP and MIBG uptake was frequently observed and associated with hypokinesis. I-123-BMIPP and MIBG are more sensitive for the detectio n of damaged myocardium, and the difference between perfusion and meta bolism seems to reflect myocardial stunning.