DWI and NCCT - Ischemic patterns in global anoxic brain injury

This case report highlights differences between diffusion weighted imaging (DWI) and computed tomography (CT) with respect to the extent of ischemic changes detectable in brain parenchyma during global anoxic brain injury. Brain CT in a 65 year old patient post cardiac arrest showed striking diffuse loss of Gray-White matter differentiation consistent with global anoxic brain injury while magnetic resonance imaging (MRI) performed 3 days later showed diffusion restriction and hyperintensity only in select areas. DWI hyperintensity was seen in diverse structures including the hippocampi, globus pallidus, forniceal columns, medial occipital lobes as well as the left amygdala. Although generally presumed to be the most sensitive modality for detecting parenchymal ischemia, this case demonstrates that CT may sometimes better capture the extent of parenchymal damage during anoxic brain injury.