Atypical pyogenic brain abscess evaluation by diffusion-weighted imaging: diagnosis with multimodality MR imaging.

Whether a brain abscess is apparent by imaging depends on the stage of the abscess at the time of imaging, as well as the etiology of the infection. Because conventional magnetic resonance imaging (MRI) is limited in its ability to distinguish brain abscesses from necrotic tumors, advanced techniques are required. The management of these two disease entities differs and can potentially affect the clinical outcome. We report a case having atypical imaging features of a pyogenic brain abscess on advanced MRI, in particular, on diffusion-weighted and perfusion imaging, in a patient with osteosarcoma undergoing chemotherapy.