title: Real-time MRI monitoring of transcatheter hepatic artery contrast agent delivery in rabbits.
abstract: OBJECTIVE
  We sought to test the hypothesis that transcatheter hepatic artery delivery of dilute gadolinium (Gd) in rabbits can be monitored in real-time using magnetic resonance imaging (MRI).
  
  
  METHODS
  Catheters (2F) were inserted via a femoral access into the hepatic arteries of six New Zealand White rabbits under radiographic guidance. After transfer to a 1.5-T MRI scanner, 26 separate hepatic artery injections of 2 mL of 4% Gd and 14 sham injections were performed. Real-time imaging of all injections was acquired using two-dimensional projection inversion recovery-gradient echo. Films of these 40 injections, as well as 10 random repeats, were independently reviewed in a randomized, blinded fashion by two Certificate of Added Qualification-certified interventional radiologists. Observers reported (i) if Gd injection occurred and (ii) if so, the location of delivery. For each observer, we compared sensitivity/specificity for real-time visualization of contrast injection and accuracy of injection localization. Interobserver and intraobserver variability was assessed using the kappa statistic. X-ray digital subtraction angiography was the gold standard for all MRI studies.
  
  
  RESULTS
  Both observers had a sensitivity of 100% and a specificity of 93%. Accuracy for intrahepatic contrast delivery was 77% for both observers. Accuracy for extrahepatic delivery was 92% and 96%, respectively. Both interobserver and intraobserver agreement was outstanding.
  
  
  CONCLUSIONS
  In rabbits, MRI allows for accurate real-time monitoring of transcatheter hepatic artery delivery of contrast agent. Localization accuracy is higher outside the liver than within the liver. These results can be used as a baseline reference for comparing the accuracy of delivery of Gd-tagged therapies in the future.
authors.affiliation: Department of Radiology, Northwestern University Medical School, Northwestern Memorial Hospital, 251 E. Huron St, 4-710 Feinberg, Chicago, IL 60611,USA. ksato@radiology.northwestern.edu
authors.forename: Kent T
authors.initials: KT
authors.lastname: Sato
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Larson
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Rhee
authors.forename: Riad A
authors.initials: RA
authors.lastname: Salem
authors.forename: Albert A
authors.initials: AA
authors.lastname: Nemcek
authors.forename: Taofic
authors.initials: T
authors.lastname: Mounajjed
authors.forename: Tatjana
authors.initials: T
authors.lastname: Paunesku
authors.forename: Gayle
authors.initials: G
authors.lastname: Woloschak
authors.forename: Paul
authors.initials: P
authors.lastname: Nikolaides
authors.forename: Reed A
authors.initials: RA
authors.lastname: Omary
mesh_terms: D000818:Animals; D002404:Catheterization / Q000379:methods; D003199:Computer Systems; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004621:Embolization, Therapeutic / Q000379:methods*; D005240:Feasibility Studies; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006499:Hepatic Artery / Q000378:metabolism*; D007269:Injections, Intra-Arterial; D008113:Liver Neoplasms / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011817:Rabbits; D016037:Single-Blind Method
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA