Non-enhanced computed tomography (NECT) has been the standard imaging technique to diagnosis ischemic stroke and exclude hemorrhage. NECT is often preferred to MRI because it is more commonly available in emergency settings, is less expensive and is simpler to perform on severely ill patients. The development of multidetector helical CT (MDCT) has increased the spatial resolution and decreased the required time for CT imaging, thereby permitting special imaging protocols. MDCT angiography (MD-CTA) directly visualizes the intra- and extracranial arteries and thus can be used to identify vascular stenosis or occlusion. Perfusion MDCT (MD-CTP) dynamically assesses the cerebral microvasculature and thus permits quantification of the extent of reversibly and irreversibly damaged brain tissue.
The combined use of all three CT modalities (NECT, MD-CTA and MD-CTP) provides a wealth of information on altered brain anatomy, large vessel status and tissue hemodynamics. Several teams of neuroradiologists have tested the safety, feasibility and diagnostic value of comprehensive, multimodal CT in acute stroke.