Discrimination of capsular stage brain abscesses from necrotic or cystic neoplasms using diffusion-weighted magnetic resonance imaging.

Object: The authors' aim was to assess the ability of apparent diffusion coefficient (ADC) ratios in distinguishing brain abscesses from cystic or necrotic neoplasms.

Methods: Fifty-three patients with rim-enhancing masses in the brain observed on T1-weighted MR images were included: 26 had abscesses (14 bacterial, six nonbacterial, and six of unknown origin), 11 had glioblastoma multiforme, and 16 had rim-enhancing metastasis. The ADC values, derived from diffusion-weighted imaging, were measured in the most homogeneous portion of the cystic component of the mass.