title: Evaluation of heart time-activity curves as a predictor of hepatic extraction of 99mTc-mebrofenin in dogs.
abstract: In this study, heart time-activity curve, created following intravenous injection of 99mTc-mebrofenin were used to quantify hepatic function in normal dogs and dogs with induced hepatic parenchymal cell damage. The results were compared to a direct measurement of hepatic extraction following mesenteric venous injection of 99mTc-mebrofenin. The heart time-activity curves were normalized and the area under the curve from 0-30 minutes and 0-60 minutes were determined. In addition, the half-time clearance rate of the heart time-activity curve was analyzed using a two-compartment model. Linear regression analysis was used to describe the relationship between the area under the normalized heart time-activity curve and hepatic extraction. There was good correlation between the area under the normalized heart time-activity curve and hepatic extraction. The best correlation was obtained from the 0-30 minute data (r2 = 0.92). A formula for calculating hepatic extraction was derived using linear regression analysis: Hepatic extraction = 1.092 - (0.0000308 x AUC0-30 minutes). There was good correlation between the half-time clearance rates from the heart time-activity curve and hepatic extraction. The best correlation was between the fast phase half-time clearance and hepatic extraction (r2 = 0.88). The area under a normalized heart time-activity curve can be used as a simple alternative to deconvolutional analysis for the determination of hepatic extraction as a measure of hepatic parenchymal cell function in the dog.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071, USA.
authors.forename: G B
authors.initials: GB
authors.lastname: Daniel
authors.forename: R
authors.initials: R
authors.lastname: DeNovo
authors.forename: A
authors.initials: A
authors.lastname: Bahr
authors.forename: G T
authors.initials: GT
authors.lastname: Smith
mesh_terms: D000814:Aniline Compounds; D000818:Animals; D019540:Area Under Curve; D004283:Dog Diseases / Q000000981:diagnostic imaging*; D004285:Dogs / Q000502:physiology*; D005260:Female; D005998:Glycine; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D007098:Imino Acids / Q000493:pharmacokinetics* / Q000494:pharmacology; D008099:Liver / Q000000981:diagnostic imaging* / Q000378:metabolism; D008107:Liver Diseases / Q000000981:diagnostic imaging / Q000662:veterinary*; D008297:Male; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics* / Q000494:pharmacology; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics* / Q000494:pharmacology; D011996:Records / Q000662:veterinary; D012189:Retrospective Studies
chemical_list: D000814:Aniline Compounds; D007098:Imino Acids; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C034837:technetium Tc 99m mebrofenin; D005998:Glycine