Non-invasive detection and quantification of acute myocardial infarction in rabbits using mono-[123I]iodohypericin microSPECT.
OBJECTIVE
Mono-[(123)I]iodohypericin ([(123)I]MIH) has been reported to have high avidity for necrosis. In the present study, by using rabbit models of acute myocardial infarction, we explored the suitability of [(123)I]MIH micro single photon emission computed tomography (microSPECT) for non-invasive visualization of myocardial infarcts in comparison with [(13)N]ammonia micro positron emission tomography (microPET) imaging, postmortem histomorphometry, and [(123)I]MIH autoradiography.


RESULTS
Fourteen rabbits were divided into four groups. The left circumflex coronary artery was permanently occluded in group A (n = 3), reperfused by releasing the ligature after 15 min in group B (n = 3) or 90 min in group C (n = 6), or not occluded in group D (n = 2). Animals received [(13)N]ammonia microPET perfusion imaging 18 h after infarct induction followed by microSPECT imaging at 2-3.5, 9-11, and 22-24 h post injection (p.i.) of [(123)I]MIH. The cardiac images were assembled into polar maps for assessment of tracer uptake. Animals were sacrificed and the excised heart was sliced for autoradiography, triphenyl tetrazolium chloride, and haematoxylin-eosin staining. Using [(123)I]MIH microSPECT, infarcts were well delineated at 9 h p.i. Mean microSPECT infarct size was 38.8 and 32.7% of left ventricular area for groups A and C, respectively, whereas group B showed low uptake of [(123)I]MIH. Highest mean infarct/viable tissue activity ratio of 61/1 was obtained by autoradiography in group C animals at 24 h p.i.


CONCLUSIONS
The study indicates the suitability of [(123)I]MIH for in vivo visualization of myocardial infarcts.
D000818:Animals; D000873:Anthracenes; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D006321:Heart / Q000000981:diagnostic imaging*; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology; D009336:Necrosis / Q000000981:diagnostic imaging; D010569:Perylene / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D011817:Rabbits; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D000873:Anthracenes; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D010569:Perylene; C004965:hypericin