Reversible delayed posthypoxic leukoencephalopathy

Abstract

Hypoxic ischemic encephalopathy may cause early deep white matter abnormalities on MR imaging that usually progress to include gray matter and basal ganglia change. Toxic leukoencephalopathy due to heroin inhalation predominantly causes cerebellar and posterior cerebral radiologic change. Both conditions rarely present clinically and radiologically in a delayed manner with subsequent recovery. We report a case of reversible delayed posthypoxic/toxic leukoencephalopathy with no clinical or radiologic evidence of gray matter insult.

Fig 1.

A, Initial axial T2-weighted MR image (obtained on day 22 postictus) through the basal ganglia shows diffuse subcortical white matter change with gray matter sparing. B, Initial axial T2-weighted MR image shows extensive bilateral symmetric supraventricular white matter change.

Fig 2.

A and B, Axial T2-weighted MR image of brain (obtained on day 24 postinsult) demonstrates extensive bilateral symmetric white matter hyperintensity extending subcortically, with sparing of the basal ganglia deep gray matter and cortical structures. C, Diffusion-weighted image (DWI) obtained 24 days after initial insult shows leukoencephalopathy, with high signal intensity on isotropic imaging. D, Apparent diffusion coefficient (ADC) mapping confirms restricted diffusion of the cerebral white matter.

Fig 3.

A and B, T2-weighted axial MR image of brain obtained 6 months after initial presentation shows improvement in white matter hyperintensities without volume loss. C, DWI obtained 6 months after initial presentation demonstrates a resolving leukoencephalopathy. D, ADC mapping confirms resolution of the previously restricted diffusion profile.