Present status of magnetic resonance imaging and spectroscopy in animal stroke models.

Magnetic resonance imaging (MRI) is based on a wide variety of physical parameters, which, in principle, can all influence the image contrast conditions. As these diverse variables are validated by independent physiological, metabolic, hemodynamic, and histological techniques, a physiological MRI evolves. This imaging modality has been successfully applied to experimental stroke studies, covering a broad range of raised questions. In the present review, we present an overview of possible physiological criteria to be studied by in vivo MRI and magnetic resonance spectroscopy, and critically analyze the present limits and future potential of the imaging technique for experimental stroke investigations. The documented applications cover the spectrum from morphological-structural details of the lesion to hemodynamic and metabolic alterations, inflammatory reaction, evaluation of thrombolytic treatment, studies on recovery of functional brain activation by functional MRI, and, finally, the most recent applications of exploring stem cells for regenerative therapy.