Imaging of acute ischemic brain injury: the return of computed tomography

Classical and modern computed tomography imaging techniques, including conventional computed tomography, perfusion-computed tomography and computed tomography-angiography for acute stroke are reviewed.

Thrombolysis has become an approved therapy for acute stroke. However, many stroke patients do not benefit from such treatment, since the presently used criteria are very restrictive, notably with respect to the accepted time-window. Even so, a significant rate of intracranial hemorrhage still occurs. Conventional cerebral computed tomography has been proposed as a selection tool for acute stroke patients. Recently, more modern computed tomography techniques, referred to as functional computed tomography or perfusion-computed tomography, have been introduced. Such perfusion-computed tomography techniques are competing favorably with diffusion-weighted/perfusion-weighted magnetic resonance imaging in the delineation of the penumbra. They are more easy to perform, because they are readily available and accessible in emergency settings, and less time-consuming. Furthermore, perfusion-computed tomography combined with computed tomography-angiography affords a comprehensive non-invasive survey of acute stroke patients as early as at the time of their emergency admission, with accurate demonstration of the site of arterial occlusion and its hemodynamic and pathophysiological repercussions for the brain parenchyma.

A renewal of computed tomography in the field of stroke has been afforded by the introduction of functional techniques such as perfusion-computed tomography, which provides promising insights into cerebral tissue viability and can be used as a guidance tool for therapy when combined with computed tomography-angiography.