title: Comparative study of iodine-123-labeled hypericin and (99m)Tc-labeled hexakis [2-methoxy isobutyl isonitrile] in a rabbit model of myocardial infarction.
abstract: Identification of myocardial infarction (MI) by imaging is critical for clinical management of ischemic heart disease. Iodine-123-labeled hypericin (¹²³I-Hyp) is a new potent infarct avid agent. We sought to compare target selectivity and organ distribution between ¹²³I-Hyp and the myocardial perfusion agent, technetium-99m-labeled hexakis [2-methoxy isobutyl isonitrile] ((99m)Tc-Sestamibi) in rabbits with acute MI. Hypericin was radiolabeled with I using iodogen as oxidant, and (99m)Tc-Sestamibi was prepared from a commercial kit and radioactive sodium pertechnetate. Rabbits (n = 6) with 24-hour-old MI received ¹²³I-Hyp intravenously and received (99m)Tc-Sestamibi 9 hours later. They were studied by dual-isotope simultaneous acquisition micro single photon emission computed tomography/computed tomography (DISA-μSPECT/CT), tissue gamma counting (TGC), autoradiography, and histology. After purification, ¹²³I-Hyp was obtained with radiochemical purity around 99%. DISA-μSPECT/CT images showed ¹²³I-Hyp retention in infarcted but not in normal myocardium. By TGC, accumulation values reached 1.175 ± 0.096 percentage of injected dose per gram (%ID/g) and 0.028 ± 0.007%ID/g in infarcted myocardium and normal myocardium with high tracer concentration in liver, intestines, and gallbladder. (99m)Tc-Sestamibi was prepared with radiochemical purity over 95%. DISA-μSPECT/CT showed no accumulation in MI and high initial radioactivity levels in normal myocardium that were rapidly cleared as confirmed by TGC (0.011 ± 0.003%ID/g). Liver and intestines were clearly visualized. By TGC, gallbladder and kidneys show moderate (99m)Tc-Sestamibi uptake. The selectivity of ¹²³I-Hyp for infarcted myocardium and (99m)Tc-Sestamibi for normal myocardium was confirmed. ¹²³I-Hyp distribution in rabbits is characterized by hepatobiliary excretion. (99m)Tc-Sestamibi undergoes hepatorenal elimination.
authors.affiliation: *Department of Imaging & Pathology and †Molecular Small Animal Imaging Centre/MoSAIC, Faculty of Medicine, Biomedical Sciences Group, KU Leuven, Leuven, Belgium; ‡Nuclear Medicine Section, University Hospital Group, UZ Leuven, Leuven, Belgium; and §Faculty of Pharmaceutical Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium.
authors.forename: Marlein M
authors.initials: MM
authors.lastname: Cona
authors.forename: Yuanbo
authors.initials: Y
authors.lastname: Feng
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Kathleen
authors.initials: K
authors.lastname: Vunckx
authors.forename: Lin
authors.initials: L
authors.lastname: Zhou
authors.forename: Katrien
authors.initials: K
authors.lastname: Van Slambrouck
authors.forename: Ahmadreza
authors.initials: A
authors.lastname: Rezaei
authors.forename: Olivier
authors.initials: O
authors.lastname: Gheysens
authors.forename: Johan
authors.initials: J
authors.lastname: Nuyts
authors.forename: Alfons
authors.initials: A
authors.lastname: Verbruggen
authors.forename: Raymond
authors.initials: R
authors.lastname: Oyen
authors.forename: Yicheng
authors.initials: Y
authors.lastname: Ni
mesh_terms: D000818:Animals; D000873:Anthracenes; D001345:Autoradiography; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000473:pathology; D004195:Disease Models, Animal; D015902:Gamma Cameras; D006207:Half-Life; D006321:Heart / Q000000981:diagnostic imaging*; D007457:Iodine Radioisotopes; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D009336:Necrosis; D010569:Perylene / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D011817:Rabbits; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013667:Technetium; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed
chemical_list: D000873:Anthracenes; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D010569:Perylene; D013667:Technetium; C004965:hypericin; D017256:Technetium Tc 99m Sestamibi