The early CT findings of cerebral infarction include an obscuration of the lentiform nucleus, slight decrease in tissue attenuation, and effacement of the cortical sulci. Dense middle cerebral artery (MCA) sign is an early marker of thromboembolic occlusion of MCA. A novel adaptive partial median filter can improve detection of slightly hypoattenuated areas. Z-score mapping based on a voxel-by-voxel analysis can also help evaluate hypoattenuation areas. Perfusion CT can provide information about brain perfusion, which permits differentiation between ischemic penumbra and irreversibly damaged brain tissue. CT angiography can help detect occlusive or severely stenosed vessels, with collateral pathway via leptomeningeal anastomosis. Potential usefulness of 320-row detector CT in evaluating ischemic cerebrovascular disease is also described.