Curvilinear T1 hyperintense lesions representing cortical necrosis after cerebral infarction.

Curvilinear T1 hyperintense lesions in the cerebral cortex in patients with subacute infarction were investigated for: (1) the presence or absence of T2* hypointensity and (2) correlations with neuropathologic findings. Thirty-six consecutive patients with subacute to chronic embolic infarction, in whom curvilinear hyperintense lesions in the infarcted cortex were seen on T1-weighted images, underwent echo-planar gradient-echo (GRE-EPI) T2*-weighted imaging. GRE-EPI T2*-weighted imaging revealed no evidence of hemorrhage within the curvilinear T1 hyperintense lesions of the cerebral cortex in all of the patients. In 11 of the 36 patients, focal hypointense lesions were seen in the depth of infarcted gyri on GRE-EPI T2*-weighted images. In the remaining 25 patients, no T2* hypointensities were seen in the infarct zone. Pathological correlation was performed in a patient with middle cerebral artery infarction and curvilinear hyperintense lesions on postmortem T1-weighted images. In the autopsied brain, curvilinear T1 hyperintense lesions corresponded to necrosis of all the cortical layers on histological examination. These data suggest that curvilinear hyperintense lesions in the cerebral cortex on T1-weighted images during the subacute to chronic period of cerebral infarction may not represent hemorrhage.