title: Development of an intrabiliary MR imaging-monitored local agent delivery technique: a feasibility study in pigs.
abstract: OBJECTIVE
  To investigate the feasibility of using magnetic resonance (MR) imaging to monitor intrabiliary delivery of motexafin gadolinium (MGd) into pig common bile duct (CBD) walls.
  
  
  METHODS
  Animal studies were approved by the Institutional Animal Care and Use Committee. Initially, human cholangiocarcinoma cells were treated with various concentrations of MGd, a compound serving as a T1-weighted MR imaging contrast agent, chemotherapy drug, and cell marker. These cells were then examined by means of confocal microscopy to confirm the intracellular uptake of MGd. In addition, an MGd/trypan blue mixture was locally infused into CBD walls of six cadaveric pigs using a microporous balloon catheter. CBDs of six pigs were infused with saline to serve as controls. Ex vivo T1-weighted MR imaging of these CBDs was performed. For in vivo technical validation, the microporous balloon catheter was placed in the CBD by means of a transcholecytic access to deliver MGd/trypan blue into CBD walls of six living pigs. T1-weighted images were obtained with both a surface coil and an intrabiliary MR imaging guidewire, and contrast-to-noise ratios of CBD walls before and after MGd/trypan blue infusions were compared in the two groups by means of paired t test, with subsequent histologic analysis to confirm the penetration and distribution of the MGd/trypan blue agent into CBD walls.
  
  
  RESULTS
  In vitro experiments confirmed uptake of MGd by human cholangiocarcinoma cells. The ex vivo experiments demonstrated the penetration of MGd/trypan blue into the CBD walls. The in vivo experiment confirmed the uptake of MGd/trypan blue, showing an increased contrast-to-noise ratio for the CBD after administration of the mixture, compared with images obtained prior to MGd/trypan blue administration (11.6 ± 4.2 [standard deviation] vs 5.7 ± 2.8; P = .04). Histologic results depicted the blue dye stains and red fluorescence of MGd in CBD walls, confirming the imaging findings.
  
  
  CONCLUSIONS
  It is feasible to use MR imaging to monitor the penetration of locally delivered MGd into pig CBD walls.
authors.affiliation: Image-guided Bio-Molecular Intervention Research and Section of Vascular and Interventional Radiology, Department of Radiology, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, 815 Mercer St, Room S470, Seattle, WA 98109, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.forename: Jiakai
authors.initials: J
authors.lastname: Li
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Meng
authors.forename: Jihong
authors.initials: J
authors.lastname: Sun
authors.forename: Stephanie S
authors.initials: SS
authors.lastname: Soriano
authors.forename: Patrick
authors.initials: P
authors.lastname: Willis
authors.forename: Huidong
authors.initials: H
authors.lastname: Gu
authors.forename: David
authors.initials: D
authors.lastname: Glickerman
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D001650:Bile Duct Neoplasms / Q000378:metabolism*; D001653:Bile Ducts, Intrahepatic / Q000378:metabolism*; D002404:Catheterization; D018281:Cholangiocarcinoma / Q000378:metabolism*; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems; D005240:Feasibility Studies; D005471:Fluoroscopy; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008665:Metalloporphyrins / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D018613:Microscopy, Confocal; D013552:Swine; D014343:Trypan Blue / Q000008:administration & dosage / Q000493:pharmacokinetics; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D003287:Contrast Media; D008665:Metalloporphyrins; C437683:motexafin gadolinium; D014343:Trypan Blue