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Abstract #0758

MRI as Witness for Acute Stroke Patients with Unknown Onsets

Ona Wu1, Lawrence L. Latour2, Shlee S. Song3, Karen L. Furie4, Steven Warach2, Lee H. Schwamm4

1Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; 2National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States; 3Department of Neurology, Cedar Sinai Medical Center, Los Angeles, CA, United States; 4Department of Neurology, Massachusetts General Hospital, Boston, MA, United States

MR WITNESS is a multi-center clinical trial of thrombolysis in acute stroke patients with unwitnessed onset. Enrolled subjects must exhibit MRI patterns consistent with early stage stroke: FLAIR negative or exhibit FLAIR signal intensity increase less than 15% compared to normal tissue. We investigated the inter-rater and inter-site reproducibility of this algorithm among 15 readers from two sites. We compared the performance to a simpler qualitative assessment of FLAIR positive or negative. We found that combining FLAIR+signal intensity had Fleiss κ=0.89 compared to κ=0.74 using simple FLAIR assessments. MR WITNESS algorithm is a robust, and reproducible approach.

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Keywords

acute agreement among apparent approved assessment basis biomedical blue cedar classification classified classifying clinical coefficient coefficients coincident combined combines combining confidence conjunction consistent consoles correctly correlation corresponds develop diameter diffusion dimension diseases early easily either eligible evaluate evident example excellent exception excluded exists findings flair formal general giving gold good greatest hence hospital hours identify identifying improve improvement individually infarct institute institutes instructed intensity inter interval intraclass intravenous investigate involving kappa kappas known label late least lesion lesions limit limiting maintaining maps measured median medical national negative negativity neurological neurology onset onsets open opposite patient patients patterns performance placement positive potentially qualitative qualitatively quantitative rater reader readers readings reads recent regarding reported reproducibility reproducible robust rules select sensitivity setting several side significantly simple site sites slice software song sought special specificity stage stages stroke strokes studies subjects suggest suggested therapy training treatment trial typically unclear unwitnessed variation visible whether witness witnessed