“Dazed and diffused”: making sense of diffusion abnormalities in neurologic pathologies

Abstract

To review diffusion abnormalities seen in diffusion-weighted MRI in neurological pathologies. We examine the clinical significance of the abnormalities in a broad spectrum of neurological diseases and highlight our current understanding of their causes. Diffusion abnormalities seen on diffusion-weighted MRI can play an important role in the diagnosis and follow-up of a broad spectrum of neurological diseases. A thorough understanding of the appearance and significance of these abnormalities is critical in patient management.Although the best known use of diffusion-weighted imaging (DWI) in MRI of the brain is detection of acute vaso-occlusive infarct, diffusion abnormalities occur in a wide spectrum of neurological pathologies. These diffusion abnormalities provide information that can directly affect the management of a patient, whether identifying pathology that would otherwise go unrecognised, narrowing a broad differential diagnosis, identifying conditions that require emergent intervention, evaluating response to treatment or providing prognostic information about a patient's expected clinical course. In this review, we explain the significance of diffusion abnormalities in a variety of neurological diseases and highlight our current understanding of the causes of these diffusion abnormalities.

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