Acute stroke in cats: comparison of dynamic susceptibility-contrast MR imaging with T2- and diffusion-weighted MR imaging.

Abstract

To evaluate the hemodynamics of acute stroke in cats by means of dynamic susceptibility-contrast magnetic resonance (MR) imaging compared with standard T2- and diffusion-weighted MR imaging. Unilateral permanent occlusion of the middle cerebral artery was performed in 18 cats. MR imaging was performed with each method 2 hours (n = 2), 6 hours (n = 10), and 24 hours (n = 11) after occlusion. At every time point, dynamic MR images clearly showed ischemic regions of steady-state signal hyperintensity and areas of less dynamic decrease in signal intensity that corresponded closely to those seen on diffusion-weighted MR images. T2-weighted MR images did not reveal regions of high signal intensity 2 hours after occlusion. The measurements of relative blood volume obtained with the dynamic method were significantly lower in steady-state hyperintense ischemic areas of the affected side than those in the contralateral normal areas at 6 and 24 hours (P < .001). This dynamic method can advance the time of detection of early ischemia in comparison with T2-weighted MR imaging and provides functional information about hemodynamics not provided by other methods of MR imaging.