title: MRI of hepatic epithelioid hemangioendothelioma (HEH).
abstract: OBJECTIVE
  To investigate magnetic resonance imaging (MRI) characteristics of hepatic epithelioid hemangionendothelioma (HEH).
  
  
  METHODS
  The study was exempted from formal Ethics Committee approval due to its retrospective and noninvasive nature. Eleven patients with histology-proven HEH were collected from six different institutions in a 5-year time period. In all patients a contrast-enhanced MR study was available. Two experienced reviewers in consensus retrospectively noted potential MR findings of HEH. Reviewers separately analyzed morphological findings, tumor signal intensity, HEH contrast enhancement pattern, and tumor appearance on hepatobiliary phase and diffusion-weighted imaging (DWI). The frequency of various findings was calculated.
  
  
  RESULTS
  The most frequent presentation was a peripheral distribution of the lesions (72.7%), target appearance on T2-weighted images (63.6%), low signal intensity on T1-weighted images (63.6%), ring or target-like enhancement at dynamic study (63.6%), and coalescence of nodules and capsular retraction (45.4%). Lack of hepatobiliary enhancement (5/8 patients) or "entrapment" hepatobiliary enhancement (3/8 patients) as well as target appearance at DWI (5/6 patients) was also observed in our series.
  
  
  CONCLUSIONS
  Although quite variable imaging appearances were seen, a target appearance on the T2-weighted image, ring or target enhancement at dynamic study, lack of enhancement or "entrapment" at hepatobiliary phase, and target appearance on DWI are frequent findings of HEH.
authors.affiliation: Department of Radiology, San Giovanni-Addolorata Hospital, Rome, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Paolantonio
authors.forename: Andrea
authors.initials: A
authors.lastname: Laghi
authors.forename: Angelo
authors.initials: A
authors.lastname: Vanzulli
authors.forename: Luigi
authors.initials: L
authors.lastname: Grazioli
authors.forename: Gianni
authors.initials: G
authors.lastname: Morana
authors.forename: Alfonso
authors.initials: A
authors.lastname: Ragozzino
authors.forename: Stefano
authors.initials: S
authors.lastname: Colagrande
mesh_terms: D000328:Adult; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA; D018323:Hemangioendothelioma, Epithelioid / Q000473:pathology*; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives; D008875:Middle Aged; D009942:Organometallic Compounds; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C073590:gadolinium ethoxybenzyl DTPA; C064572:gadobenic acid; D008536:Meglumine; D019786:Gadolinium DTPA
keywords: DWI; HEH; MRI; hepatic epithelioid hemangionendothelioma; liver; liver-specific contrast agent