title: Diffusion-weighted MR imaging: diagnostic accuracy in patients imaged within 6 hours of stroke symptom onset.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of diffusion-weighted magnetic resonance (MR) imaging performed within 6 hours of the onset of stroke symptoms.
  
  
  METHODS
  The authors reviewed the patient records and images from all patients hospitalized in a 10-month period in whom diffusion-weighted imaging was performed within 6 hours of the onset of strokelike symptoms (n = 22). Analyses included comparison of the initial interpretation of the diffusion-weighted images with the final clinical diagnosis; blinded reviews of computed tomographic (CT) scans and conventional and diffusion-weighted images; and determination of lesion contrast-to-noise ratios (CNRs).
  
  
  RESULTS
  Diffusion-weighted images indicated stroke in 14 patients, all of whom had a final diagnosis of acute stroke. Diffusion-weighted images were negative in eight patients, all of whom had a final clinical diagnosis other than stroke (100% sensitivity, 100% specificity, chi 2 = 23.00, P < .0001). Blinded reviews yielded 100% sensitivity and 86% specificity for diffusion-weighted MR imaging (chi 2 = 15.43, P < .0005); 18% sensitivity and 100% specificity for conventional MR imaging (chi 2 = 2.85, P > .2); and 45% sensitivity and 100% specificity for CT (chi 2 = 4.40, P > .10). Lesion percentage CNRs were 77% for diffusion-weighted imaging, 5.5% for CT, 9.8% for T2-weighted MR imaging, and 3.1% for proton-density-weighted MR imaging (P < .002 for diffusion-weighted imaging vs others).
  
  
  CONCLUSIONS
  Diffusion-weighted MR imaging is highly accurate for diagnosing stroke within 6 hours of symptom onset and is superior to CT and conventional MR imaging.
authors.affiliation: Division of Neuroradiology, Massachusetts General Hospital and Harvard Medical School, Boston 02114-2696, USA.
authors.forename: R G
authors.initials: RG
authors.lastname: González
authors.forename: P W
authors.initials: PW
authors.lastname: Schaefer
authors.forename: F S
authors.initials: FS
authors.lastname: Buonanno
authors.forename: L H
authors.initials: LH
authors.lastname: Schwamm
authors.forename: R F
authors.initials: RF
authors.lastname: Budzik
authors.forename: G
authors.initials: G
authors.lastname: Rordorf
authors.forename: B
authors.initials: B
authors.lastname: Wang
authors.forename: A G
authors.initials: AG
authors.lastname: Sorensen
authors.forename: W J
authors.initials: WJ
authors.lastname: Koroshetz
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D002561:Cerebrovascular Disorders / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013997:Time Factors; D014057:Tomography, X-Ray Computed