title: Evaluation of 99Tcm-bicisate as a renal imaging agent.
abstract: 99Tcm-bicisate (99Tcm-ECD), often used as a brain perfusion agent, is rapidly converted following intravenous injection to the polar monoacid (99Tcm-ECM) and diacid (99Tcm-EC) metabolites. Such polar metabolites, which are eliminated principally by renal clearance, are potential renal imaging agents. In this study, 99Tcm-ECD was compared for the first time with 99Tcm-EC, 99Tcm-mercaptoacetyltriglycine (99Tcm-MAG3) and 131I-orthoiodohippurate (OIH) as renal imaging agents in rabbits. Whole-body images and renograms were obtained for all three of the 99Tcm agents, and pharmacokinetic parameters including plasma and urinary clearance were studied for all four agents. The plasma clearance of 99Tcm-EC (37 ml min-1) was slower than that of 99Tcm-ECD (51 ml min-1), which could be accounted for by the higher liver uptake of 99Tcm-ECD. The urinary clearance of 99Tcm-ECD (35 ml min-1), 99Tcm-EC (34 ml min-1) and 99Tcm-MAG3 (39 ml min-1) was similar. The renal images obtained with 99Tcm-ECD were comparable to those for 99Tcm-MAG3 and 99Tcm-EC. However, liver uptake was more prominent with 99Tcm-ECD than with the other agents. The 99Tcm-ECD renogram curves showed a prolonged decrease in renal activity compared to both 99Tcm-EC and 99Tcm-MAG3. In potential human studies, the relatively high liver uptake of 99Tcm-ECD superimposed on right renal activity may be a limitation. Therefore, we conclude that 99Tcm-ECD is less favourable when compared to existing renal agents due to its high extrarenal uptake and renal kinetics.
authors.affiliation: Division of Nuclear Medicine, Medical College of Wisconsin, Milwaukee 53226, USA.
authors.forename: K
authors.initials: K
authors.lastname: Ozker
authors.forename: L
authors.initials: L
authors.lastname: Kabasakal
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: R S
authors.initials: RS
authors.lastname: Hellman
authors.forename: A
authors.initials: A
authors.lastname: Isitman
authors.forename: A Z
authors.initials: AZ
authors.lastname: Krasnow
authors.forename: B D
authors.initials: BD
authors.lastname: Collier
mesh_terms: D000818:Animals; D001711:Biotransformation; D003545:Cysteine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D007465:Iodohippuric Acid / Q000493:pharmacokinetics; D007668:Kidney / Q000000981:diagnostic imaging* / Q000378:metabolism; D008657:Metabolic Clearance Rate; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D011817:Rabbits; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017263:Technetium Tc 99m Mertiatide / Q000493:pharmacokinetics
chemical_list: D007457:Iodine Radioisotopes; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D007465:Iodohippuric Acid; D017263:Technetium Tc 99m Mertiatide; C059659:technetium Tc 99m bicisate; D003545:Cysteine