title: Peripheral Restricted Diffusion: A Common Appearance of Hepatic Abscesses.
abstract: OBJECTIVE
  Evaluate the frequency of the classic, central diffusion restriction pattern within hepatic abscesses versus other patterns.
  
  
  METHODS
  Retrospective review of 42 hepatic abscesses from our institution. Three independent reviewers assessed the pattern of diffusion restriction: central or noncentral. Clinical information including chronicity of symptoms, organism, and leukocyte values were recorded.
  
  
  RESULTS
  Patterns of diffusion restriction were variable in our population with only a minority (26%) of lesions showing a central pattern. Among other patterns, peripheral restriction was present in 42% of the cases. Central diffusion restriction was associated with smaller abscesses. Duration of symptoms was not associated with restriction pattern. Inter-reader agreement for pattern description was moderate (κ = 0.52).
  
  
  CONCLUSIONS
  Liver abscesses have a much more variable appearance than previously described, with both central and peripheral diffusion restriction patterns observed frequently. Given this variability, caution should be exercised in differentiating abscess from neoplasm because the appearance may overlap.
authors.affiliation: From the Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO.
authors.forename: Mark M
authors.initials: MM
authors.lastname: Hammer
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Mellnick
authors.forename: Constantine A
authors.initials: CA
authors.lastname: Raptis
authors.forename: Ryan
authors.initials: R
authors.lastname: Schmidt
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Fowler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology*; D008100:Liver Abscess / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult