Advances in neuroimaging of acute stroke.

As therapeutic options for treating acute stroke evolve, neuroimaging strategies are assuming an increasingly important role in the initial evaluation and management of patients. There is a recognized need for objective neuroimaging methods to identify the best candidates for early intervention. Both acute and long-term treatment decisions for stroke patients should optimally incorporate information provided by neuroimaging studies regarding tissue viability (eg, size, location, vascular distribution, degree of reversibility of ischemic injury, presence of hemorrhage), vessel status (site and severity of stenoses and occlusions), and cerebral perfusion (size, location, and severity of hypoperfusion). The ability to acutely identify the ischemic penumbra and to use this information to make treatment decisions may be within reach, particularly with the multimodal data provided by magnetic resonance techniques. This article will review recent developments in the field of neuroimaging of acute stroke and discuss the clinical applications of specific techniques of magnetic resonance imaging, computed tomography, positron emission tomography, single photon emission tomography, catheter angiography, and ultrasound imaging.