TY - JOUR T1 - Diffusion-Negative Stroke: A Report of Two Cases JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1876 LP - 1880 VL - 20 IS - 10 AU - Paul Y-K. Wang AU - Peter B. Barker AU - Robert J. Wityk AU - Aziz M. Uluğ AU - Peter C. M. van Zijl AU - Norman J. Beauchamp, Jr Y1 - 1999/11/01 UR - http://www.ajnr.org/content/20/10/1876.abstract N2 - Summary: Diffusion-weighted MR imaging is generally thought to be highly sensitive for the diagnosis of acute stroke. We report two cases of hyperacute stroke with absence of changes on diffusion-weighted images within 4 hours of symptom onset. Follow-up studies, performed 4 days later, showed infarction in regions compatible with the clinical presentation and (in one case) with the initial perfusion deficit. These cases indicate that normal findings on diffusion-weighted images in patients with suspected cerebral ischemia do not rule out impending infarction. ER -