Peripheral restricted diffusion: A common appearance of hepatic abscesses

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. Interreader 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.