title: Nontumorous hepatic arterial-portal venous shunts: MR imaging findings.
abstract: OBJECTIVE
  To determine the magnetic resonance (MR) imaging findings of small nontumorous hepatic arterial-portal venous (arterioportal) shunts in the liver.
  
  
  METHODS
  MR images in 25 patients with 38 small nontumorous arterioportal shunts verified with surgery or follow-up imaging were included in this study. The causes of arterioportal shunts were iatrogenic causes in 11 patients and/or cirrhotic changes in the remaining patients. Nonenhanced T1- and T2-weighted images and multiphase contrast material-enhanced dynamic images were retrospectively reviewed and compared with conventional hepatic arteriograms to determine the MR characteristics related to the focal hemodynamic changes.
  
  
  RESULTS
  On arterial-dominant-phase dynamic MR images, 29 (76%) of the 38 arteriographically suggested nontumorous arterioportal shunts displayed abnormal findings distinguished against the surrounding hepatic parenchyma, including wedge-shaped (n = 14), nodular (n = 9), or irregularly outlined (n = 6) areas of focal contrast enhancement. The signal intensity on nonenhanced T1- and T2-weighted images of the corresponding areas appeared unremarkable except for three wedge-shaped high-signal-intensity areas (three [8%] of 38) on T2-weighted images accompanied by prolonged contrast enhancement. Most (24 [83%] of 29) areas of abnormal signal intensity were located at the periphery of the liver parenchyma.
  
  
  CONCLUSIONS
  A small nontumorous arterioportal shunt should be considered one of the causes of focal parenchymal hyperperfusion abnormalities on contrast-enhanced dynamic MR images of the liver in the absence of abnormal signal intensity on static MR images.
authors: Department of Diagnostic Radiology and the Research Institute of Radiological Science, Yonsei University College of Medicine, YongDong Severance Hospital, 146-92 Dokok-Dong, Kangnam-Ku, Seoul, South Korea. yjsrad97@yumc.yonsei.ac.kr
authors: J S
authors: JS
authors: Yu
authors: K W
authors: KW
authors: Kim
authors: M G
authors: MG
authors: Jeong
authors: J T
authors: JT
authors: Lee
authors: H S
authors: HS
authors: Yoo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001165:Arteriovenous Malformations / Q000175:diagnosis*; D005260:Female; D006499:Hepatic Artery / Q000002:abnormalities*; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000002:abnormalities*; D012189:Retrospective Studies