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July 30, 2012
Not All That Restricts Diffusion Is Ischemic
Diffusion–weighted imaging (DWI) has advanced our ability to recognize ischemic stroke early and accurately. As the Brownian motion of water is impaired in acute stroke, theoretically secondary to ion–homeostasis disruption, a shift of water from the extracellular to intracellular space leads to cytotoxic edema. Afflicted areas appear "bright" on DWI and demonstrate a low apparent diffusion coefficient. However, there are many entities that can demonstrate this pattern besides ischemia including acute demyelination, cortical spreading depression, seizures, abscess, lymphoma, severe hypoglycemia, Canavan disease, and trauma.
1. Huisman TA. Diffusion–weighted imaging: basic concepts and application in cerebral stroke and head trauma. European Radiology 2003; 13: 2283–2297.
2. Huisman TA. Diffusion–weighted and diffusion tensor imaging of the brain, made easy. Cancer Imaging 2010; 4: S163–171.
Submitted by: Shaheen E Lakhan, MD, PhD, MS, MEd
Disclosures: Dr. Lakhan serves as a member of the American Academy of Neurology's Distance Learning Subcommittee and an Associate Editor for Journal of Medical Case Reports, Journal of Medical & Biological Sciences, and BMC Research.
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