Use of diffusion-weighted MR imaging in differential diagnosis between intracerebral necrotic tumors and cerebral abscesses

The differential diagnosis between intracerebral necrotic tumors and cerebr al abscesses is frequently impossible with conventional MR imaging. We repo rt two cases of cerebral abscesses that showed high signal on diffusion-wei ghted echo planar imaging and a strongly reduced apparent diffusion coeffic ient. This appearance was not present in our cases of necrotic/cystic gliom as (eight cases) and necrotic metastases (two cases). We believe that diffu sion-weighted MR imaging may be a diagnostic flue in cases of cerebral "rin g-enhancing" masses.