Real-time MRI monitoring of transcatheter hepatic artery contrast agent delivery in rabbits.
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.
Sato
Kent T
KT
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
Larson
Andrew C
AC
Rhee
Thomas K
TK
Salem
Riad A
RA
Nemcek
Albert A
AA
Mounajjed
Taofic
T
Paunesku
Tatjana
T
Woloschak
Gayle
G
Nikolaides
Paul
P
Omary
Reed A
RA
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
D003287:Contrast Media; D019786:Gadolinium DTPA