title: Evaluation of hepatic contrast enhancement with a hepatocyte-specific magnetic resonance imaging contrast agent (gadoxetic acid) in healthy dogs.
abstract: OBJECTIVE
  To determine, by means of MRI, the time to maximal contrast enhancement in T1-weighted images following IV administration of gadoxetic acid in healthy dogs and assess the impact of gadoxetic acid on the signal intensity of T2-weighted images.
  
  
  METHODS
  7 healthy dogs.
  
  
  METHODS
  No hepatic abnormalities were detected during ultrasonographic examination. Each dog was anesthetized and positioned in dorsal recumbency for MRI. Transverse T1- and T2-weighted images of the liver were acquired prior to and following (at 5-minute intervals) IV injection of 0.1 mL of gadoxetic acid/kg. Signal intensity of the liver parenchyma was measured in 3 regions of interest in the T1- and T2-weighted images before and at various times point after contrast agent administration. Time versus signal-to-noise ratio curves were plotted to determine time to maximal contrast enhancement and contrast agent-related changes in signal intensity in T2-weighted images.
  
  
  RESULTS
  Analysis of T1-weighted images revealed that mean ± SD time to maximal enhancement after gadoxetic acid injection was 10.5 ± 3.99 minutes. Signal intensity of T2-weighted images was not significantly affected by gadoxetic acid administration. No injection-related adverse effects were observed in any dog.
  
  
  CONCLUSIONS
  Results indicated that gadoxetic acid can be used for hepatic MRI in healthy dogs and the resultant hepatic enhancement patterns are similar to those described for humans. Maximal contrast enhancement occurred between 10 and 15 minutes after contrast agent injection; thus, T2-weighted images may be obtained in the interval between injection and maximal enhancement for a more time-efficient clinical protocol.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
authors.forename: Alexandra K
authors.initials: AK
authors.lastname: Bratton
authors.forename: Stephanie G
authors.initials: SG
authors.lastname: Nykamp
authors.forename: Thomas W G
authors.initials: TW
authors.lastname: Gibson
authors.forename: Robert
authors.initials: R
authors.lastname: Cruz-Arámbulo
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Kruth
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D004285:Dogs / Q000033:anatomy & histology*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D022781:Hepatocytes / Q000473:pathology; D007275:Injections, Intravenous; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000662:veterinary*; D008297:Male
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA