title: Analysis of different contrast enhancement patterns after microbubble-based contrast agent injection in liver hemangiomas with atypical appearance on baseline scan.
abstract: BACKGROUND
  We describe different possible enhancement patterns in liver hemangiomas with atypical appearance on baseline ultrasound after microbubble-based contrast agent injection.
  
  
  METHODS
  From a series of 253 consecutive lesions that were indeterminate on baseline ultrasound and then scanned after injection of air-filled microbubble contrast agent, 65 focal liver lesions were retrospectively selected on the basis of a diagnosis of liver hemangioma on multiphase contrast-enhanced computed tomography (n = 23), magnetic resonance imaging (n = 27), or histology (n = 15). Each lesion was scanned during arterial phase (30 s after microbubble injection) and late phase (5 min after injection). On-site sonologists performed retrospective assessment of contrast-enhancement patterns by consensus.
  
  
  RESULTS
  Centripetal fill-in preceded (n = 50) or not preceded (n = 3) by peripheral nodular/rim-like enhancement was the prevalently observed contrast-enhancement pattern, equivalent to the typical enhancement pattern of liver hemangiomas on contrast-enhanced computed tomography or magnetic resonance imaging. In the remaining lesions, additional enhancement patterns (diffuse contrast enhancement with rapid fill-in and a late hyper-isoechoic appearance, n = 6; peripheral nodular enhancement with a late hypoechoic appearance, n = 3; or persistent heterogeneous and hyperechoic appearance, n = 3) were observed.
  
  
  CONCLUSIONS
  Different contrast-enhancement patterns are possible in atypical liver hemangiomas after microbubble injection. Typical centripetal fill-in is the prevalent pattern and its evidence allows diagnosis.
authors.affiliation: Department of Radiology, Cattinara Hospital, University of Trieste, Strada di Fiume 447, Trieste, 34149, Italy. equaia@yahoo.com
authors.forename: E
authors.initials: E
authors.lastname: Quaia
authors.forename: T V
authors.initials: TV
authors.lastname: Bartolotta
authors.forename: M
authors.initials: M
authors.lastname: Midiri
authors.forename: S
authors.initials: S
authors.lastname: Cernic
authors.forename: M
authors.initials: M
authors.lastname: Belgrano
authors.forename: M
authors.initials: M
authors.lastname: Cova
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006391:Hemangioma / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D011134:Polysaccharides / Q000008:administration & dosage; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508