Brain abscess and necrotic or cystic brain tumor: discrimination with signal intensity on diffusion-weighted MR imaging.

Abstract
OBJECTIVE: The purpose of this study was to determine the differences in signal intensity between brain abscesses and necrotic or cystic tumors on diffusion-weighted MR imaging. CONCLUSION: Five consecutive patients with proven brain abscesses and four patients with proven cystic or necrotic brain tumors were prospectively evaluated with diffusion-weighted imaging. On diffusion-weighted imaging, brain abscesses showed markedly hyperintense signal in all five patients, whereas necrotic or cystic brain tumors revealed hypointense signal in all four patients. Diffusion-weighted imaging may allow the differentiation of brain abscess from necrotic or cystic brain tumor.