title: Color-coded fluid-attenuated inversion recovery images improve inter-rater reliability of fluid-attenuated inversion recovery signal changes within acute diffusion-weighted image lesions.
abstract: OBJECTIVE
  Diffusion-weighted image fluid-attenuated inversion recovery (FLAIR) mismatch has been considered to represent ischemic lesion age. However, the inter-rater agreement of diffusion-weighted image FLAIR mismatch is low. We hypothesized that color-coded images would increase its inter-rater agreement.
  
  
  METHODS
  Patients with ischemic stroke <24 hours of a clear onset were retrospectively studied. FLAIR signal change was rated as negative, subtle, or obvious on conventional and color-coded FLAIR images based on visual inspection. Inter-rater agreement was evaluated using κ and percent agreement. The predictive value of diffusion-weighted image FLAIR mismatch for identification of patients <4.5 hours of symptom onset was evaluated.
  
  
  RESULTS
  One hundred and thirteen patients were enrolled. The inter-rater agreement of FLAIR signal change improved from 69.9% (k=0.538) with conventional images to 85.8% (k=0.754) with color-coded images (P=0.004). Discrepantly rated patients on conventional, but not on color-coded images, had a higher prevalence of cardioembolic stroke (P=0.02) and cortical infarction (P=0.04). The positive predictive value for patients <4.5 hours of onset was 85.3% and 71.9% with conventional and 95.7% and 82.1% with color-coded images, by each rater.
  
  
  CONCLUSIONS
  Color-coded FLAIR images increased the inter-rater agreement of diffusion-weighted image FLAIR recovery mismatch and may ultimately help identify unknown-onset stroke patients appropriate for thrombolysis.
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Bum Joon
authors.initials: BJ
authors.lastname: Kim
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Yong-Hwan
authors.initials: YH
authors.lastname: Kim
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Yeon-Jung
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Ahn
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Deok Hee
authors.initials: DH
authors.lastname: Lee
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Sun U
authors.initials: SU
authors.lastname: Kwon
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Jong S
authors.initials: JS
authors.lastname: Kim
authors.affiliation: From the Departments of Neurology (B.J.K., Y.-J.K., S.H.A., S.U.K., J.S.K., D.-W.K.) and Radiology (D.H.L., S.J.K.), and Vision, Image, and Learning Laboratory (Y.-H.K., D.-W.K.), Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. dwkang@amc.seoul.kr.
authors.forename: Dong-Wha
authors.initials: DW
authors.lastname: Kang
mesh_terms: D000368:Aged; D003116:Color; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D020521:Stroke / Q000175:diagnosis*; D015912:Thrombolytic Therapy
keywords: magnetic resonance imaging; stroke