RT Journal Article SR Electronic T1 Diffusion-Negative Stroke: A Report of Two Cases JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 1876 OP 1880 VO 20 IS 10 A1 Paul Y-K. Wang A1 Peter B. Barker A1 Robert J. Wityk A1 Aziz M. Uluğ A1 Peter C. M. van Zijl A1 Norman J. Beauchamp, Jr YR 1999 UL http://www.ajnr.org/content/20/10/1876.abstract AB 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.