title: Assessment of chronological effects of irreversible electroporation on hilar bile ducts in a porcine model.
abstract: OBJECTIVE
  To evaluate the chronological effects of irreversible electroporation (IRE) on large hilar bile ducts in an in vivo porcine model correlated with computed tomography (CT) cholangiography and histopathology.
  
  
  METHODS
  Twelve IRE zones were made along hilar bile ducts intraoperatively under ultrasound (US)-guidance in 11 pigs. Paired electrodes were placed either on opposing sides of the bile duct (straddle [STR]) or both on one side of the bile duct (one-sided [OSD]). The shortest electrode-to-duct distance was classified as periductal (≤ 2 mm) or nonperiductal (>2 mm). CT cholangiography and laboratory tests were performed before IRE and again at 2 days, 4 weeks, and 8 weeks after IRE. Degree of bile duct injury were graded as follows: grade 0 = no narrowing; grade 1 = ≤ 50 % duct narrowing; grade 2 = >50 % narrowing without proximal duct dilatation; grade 3 = grade 2 with proximal duct dilatation; and grade 4 = grade 3 with enzyme elevation. Pigs were selected for killing and histopathology at 2 days, 4, and 8 weeks.
  
  
  RESULTS
  Nonperiductal electrode placement produced no long-term strictures in 5 of 5 ducts. Periductal electrode placement produced mild narrowing in 6 of 7 ducts: 5 grade 1 and 1 grade 2. None showed increased enzymes. There was no significant difference between STR versus OSD electrode placement. Histopathology showed minor but relatively greater ductal mural changes in narrowed ducts.
  
  
  CONCLUSIONS
  In the larger hilar ducts, long-term patency and mural integrity appear resistant to IRE damage with the energy deposition used, especially if the electrode is not immediately periductal in position.
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, 757 Westwood Plaza, Los Angeles, CA, 957437, USA, cooljay@korea.ac.kr.
authors.forename: Jae Woong
authors.initials: JW
authors.lastname: Choi
authors.forename: David S K
authors.initials: DS
authors.lastname: Lu
authors.forename: Ferdnand
authors.initials: F
authors.lastname: Osuagwu
authors.forename: Steven
authors.initials: S
authors.lastname: Raman
authors.forename: Charles
authors.initials: C
authors.lastname: Lassman
mesh_terms: D000818:Animals; D001652:Bile Ducts / Q000473:pathology*; D002758:Cholangiography; D004195:Disease Models, Animal; D018274:Electroporation / Q000379:methods*; D013552:Swine; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D018084:Ultrasonography, Interventional