title: Hepatic tumor invasion of bile ducts: wedge-shaped sign on MR images.
abstract: OBJECTIVE
  To clarify the diagnostic importance of wedge-shaped areas of increased signal intensity that surround liver tumors on T1-weighted magnetic resonance (MR) images.
  
  
  METHODS
  In five patients with hepatic tumors, T1-weighted MR images that demonstrated wedge-shaped areas of increased signal intensity in the liver were reviewed; findings were compared with those at surgical and histologic examinations.
  
  
  RESULTS
  MR images showed localized intrahepatic bile duct dilatation lateral (three patients) and medial (two patients) to liver tumors within the wedge-shaped areas. At histopathologic examination, intraductal tumor growth was seen in local bile ducts in the same areas in five patients, and lipofuscin deposits were seen in the cytoplasm of atrophic hepatocytes in three patients.
  
  
  CONCLUSIONS
  On T1-weighted images, wedge-shaped areas of increased signal intensity associated with liver tumors indicate intraductal tumor extension in intrahepatic bile ducts. T1 shortening is possibly caused by lipofuscin deposits in atrophic hepatocytes.
authors.affiliation: Department of Diagnostic Radiology, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Muramatsu
authors.forename: K
authors.initials: K
authors.lastname: Takayasu
authors.forename: Y
authors.initials: Y
authors.lastname: Furukawa
authors.forename: K
authors.initials: K
authors.lastname: Miyakawa
authors.forename: R
authors.initials: R
authors.lastname: Iwata
authors.forename: K
authors.initials: K
authors.lastname: Ushio
authors.forename: J
authors.initials: J
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Nakanishi
mesh_terms: D000328:Adult; D000368:Aged; D001653:Bile Ducts, Intrahepatic / Q000473:pathology*; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness