Brain infarction has different manifestations on CT scans at different stages. Generally, within 24 hours, the CT scan may not show any imaging of the cerebral infarction lesion. However, some patients, especially those with thrombosis in the middle cerebral artery, might exhibit a high density sign in the middle cerebral artery. In cases of large-scale cerebral infarction, some sulci on the side affected by the infarction may appear shallower, indicating possible brain swelling. Generally, within 24 hours, a CT scan can reveal a low-density image, which appears relatively darker. This condition is typically considered a brain infarction, and as time progresses, this dark, or low-density image, tends to become even darker. In some patients during the acute phase, although the infarction may not be apparent, a CT scan is performed to rule out bleeding, as CT is very sensitive to bleeding.