Bum Joon Kim1, Yong-Hwan Kim1, Yeon-Jung Kim1, Sung Ho Ahn1, Deok Hee Lee1, Sun U Kwon1, Sang Joon Kim1, Jong S Kim1, Dong-Wha Kang2. 1. 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. 2. 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.
Abstract
BACKGROUND AND PURPOSE: 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.
BACKGROUND AND PURPOSE: 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 strokepatients appropriate for thrombolysis.