title: Diffusion-weighted MR imaging of acute stroke: correlation with T2-weighted and magnetic susceptibility-enhanced MR imaging in cats.
abstract: We evaluated the temporal and anatomic relationships between changes in diffusion-weighted MR image signal intensity, induced by unilateral occlusion of the middle cerebral artery in cats, and tissue perfusion deficits observed in the same animals on T2-weighted MR images after administration of a nonionic intravascular T2 shortening agent. Diffusion-weighted images obtained with strong diffusion-sensitizing gradient strengths (5.6 gauss/cm, corresponding to gradient attenuation factor, b, values of 1413 sec/mm2) displayed increased signal intensity in the ischemic middle cerebral artery territory less than 1 hr after occlusion, whereas T2-weighted images without contrast usually failed to detect injury for 2-3 hr after stroke. After contrast administration (0.5-1.0 mmol/kg by Dy-DTPA-BMA, IV), however, T2-weighted images revealed perfusion deficits (relative hyperintensity) within 1 hr after middle cerebral artery occlusion that corresponded closely to the anatomic regions of ischemic injury shown on diffusion-weighted MR images. Close correlations were also found between early increases in diffusion-weighted MR image signal intensity and disrupted phosphorus-31 and proton metabolite levels evaluated with surface coil MR spectroscopy, as well as with postmortem histopathology. These data indicate that diffusion-weighted MR images more accurately reflect early-onset pathophysiologic changes induced by acute cerebral ischemia than do T2-weighted spin-echo images.
authors.affiliation: Department of Radiology, University of California, San Francisco 94143.
authors.forename: M E
authors.initials: ME
authors.lastname: Moseley
authors.forename: J
authors.initials: J
authors.lastname: Kucharczyk
authors.forename: J
authors.initials: J
authors.lastname: Mintorovitch
authors.forename: Y
authors.initials: Y
authors.lastname: Cohen
authors.forename: J
authors.initials: J
authors.lastname: Kurhanewicz
authors.forename: N
authors.initials: N
authors.lastname: Derugin
authors.forename: H
authors.initials: H
authors.lastname: Asgari
authors.forename: D
authors.initials: D
authors.lastname: Norman
mesh_terms: D000208:Acute Disease; D000818:Animals; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D002415:Cats; D002560:Cerebrovascular Circulation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009942:Organometallic Compounds / Q000008:administration & dosage; D004369:Pentetic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives; D010758:Phosphorus / Q000378:metabolism; D011522:Protons
chemical_list: D009942:Organometallic Compounds; D011522:Protons; C061756:sprodiamide; D010758:Phosphorus; D004369:Pentetic Acid