Imaging in acute brain infarction

Imaging in a patient suspected of having suffered an acute stroke is used primarily to clear the patient for thrombolytic therapy, by excluding intracranial hemorrhage and nonstroke causes of the patient's symptoms, within a critical 3-hour window. Noncontrast CT of the brain is the imaging test of choice for the initial evaluation of a patient with suspected acute ischemic stroke. It is rapid and readily available and has a high sensitivity for intracranial hemorrhage. Contrast-enhanced CT angiography and perfusion imaging may provide additional information with only a minimal increase in scanning time. Finally, diffusion-weighted magnetic resonance sequences have a high sensitivity for acute stroke and, with magnetic resonance perfusion imaging, may play an increasing role in the future treatment of stroke.