CT, CT-Angiography, and Perfusion-CT Evaluation of Stroke

A stroke is a sudden loss of neurological function due to brain parenchyma damage, caused either by the sudden loss of blood flow to a specific brain region (ischemic stroke) or by the rupture of blood vessels in the brain (hemorrhagic stroke). Patients with acute stroke usually present with a focal neurological deficit, but the clinical symptoms are not specific. Head computed tomography (CT), CT-angiography, and perfusion-CT are used in the acute setting to differentiate between the various possible etiologies for the symptoms, and help with the choice of the appropriate therapeutic approach. Noncontrast head CT is used to evaluate for the presence of a hemorrhage and/or infarcted territory. CT-angiography is used to localize the site of the occlusion and assess collateral circulation, as well as for endovascular intervention planning. Perfusion-CT can be used to characterize acute ischemic stroke and to distinguish stroke from stroke mimics, as well as has been proposed as a tool for patient selection for treatment.