Apolipoprotein E Polymorphism and Acute Ischemic Stroke: A Diffusion- and Perfusion-Weighted Magnetic Resonance Imaging Study

Diffusion- and perfusion-weighted magnetic resonance imaging (MRI) was used to study the putative effects of apolipoprotein E (ApoE) polymorphism in stroke. Thirty-one patients with acute stroke, comparative for age and gender were scanned, nine of whom were ApoE allele ***ε4 carriers. Initially, less than 24 hours from the onset of stroke, the ε4 carriers had significantly smaller volumes of hypoperfusion on relative cerebral blood volume map ( P = 0.001), and smaller infarct volumes ( P = 0.008) compared with the noncarriers. By day 8, this difference in the infarct volumes had disappeared, suggesting relatively enhanced infarct growth. On average, the total infarct volume increased 145% of the initial infarct volume in the ε4 carriers, and 84% in the noncarriers. There were strong correlations between the imaging findings and clinical status initially and with the outcome 3 months after the stroke in the ε4 noncarriers, but, with a single exception at acute phase, a lack thereof in the ε4 carriers. These patterns were virtually similar in a subgroup of patients with middle cerebral artery stroke. These data support the hypothesis of increased general vulnerability of the brain in the e4 carriers. Thus, the effects of ApoE polymorphism should be accounted for when interpreting diffusion- and perfusion-weighted MRI studies, particularly if predicting lesion growth.