title: Pseudo-obstruction of the extrahepatic bile duct due to artifact from arterial pulsatile compression: a diagnostic pitfall of MR cholangiopancreatography.
abstract: OBJECTIVE
  To evaluate the frequency of artifact from arterial pulsatile compression as the cause of pseudo-obstruction of the extrahepatic bile duct at magnetic resonance (MR) cholangiopancreatography (MRCP) and specify the causative vessels.
  
  
  METHODS
  In 234 patients (102 men, 132 women; age range, 25-80 years), MRCP images obtained by using a single-shot turbo spin-echo sequence were reviewed to assess pseudo-obstruction of the extrahepatic bile duct caused by vascular compression. Dual-phase spiral computed tomography, contrast material-enhanced three-dimensional MR angiography, and/or digital subtraction angiography also were performed to determine the vessel that caused the pseudo-obstruction.
  
  
  RESULTS
  Thirty-six pseudo-obstructions due to vascular compression were found in 33 (14%) patients. The common hepatic duct (27 [75%] sites) was the most common pseudo-obstruction site, followed by the left hepatic duct (four [11%] sites), proximal common bile duct (three [8%] sites), and right hepatic duct (two [6%] sites). The causative vessels were identified as the right hepatic artery at 24 (67%) sites; gastroduodenal artery, two (6%) sites; cystic artery, two (6%) sites; proper hepatic artery, one (3%) site; and an unspecified branch of the common hepatic artery, seven (19%) sites.
  
  
  CONCLUSIONS
  At MRCP, pseudo-obstruction of the extrahepatic bile duct can be caused by pulsatile vascular compression of the hepatic and gastroduodenal arteries, and it should not be misdiagnosed as a bile duct tumor or biliary stone.
authors.affiliation: Department of Radiology, Kurashiki Central Hospital, Japan. yw5904@kchnet.or.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Dohke
authors.forename: T
authors.initials: T
authors.lastname: Ishimori
authors.forename: Y
authors.initials: Y
authors.lastname: Amoh
authors.forename: A
authors.initials: A
authors.lastname: Okumura
authors.forename: K
authors.initials: K
authors.lastname: Oda
authors.forename: T
authors.initials: T
authors.lastname: Hayashi
authors.forename: A
authors.initials: A
authors.lastname: Hiyama
authors.forename: Y
authors.initials: Y
authors.lastname: Dodo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D001158:Arteries / Q000473:pathology; D016477:Artifacts; D017734:Bile Ducts, Extrahepatic / Q000098:blood supply*; D001651:Cholestasis, Extrahepatic / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006499:Hepatic Artery / Q000473:pathology*; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology*