A 18 year-old woman presented with headaches followed by lethargy and coma. On examination, she had papilledema. To a painful stimulus, she withdrew the left side better than the right.

Axial T2-weighted MRI scans. Note the abnormal high signal in both hemispheres, more prominent of the left, associated with mass effect. The distribution of the lesion is bilateral, frontal > parietal and paracentral. Although not specific, this pattern is consistent venous infarctions from thrombosis of the superior sagittal sinus.