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The first issue raised is primarily based on a technical misunderstanding of definitions. There is a difference between “water uptake per volume of brain” (our bioimaging marker for time interval between stroke onset and admission computed tomographic [CT] imaging) and “absolute increase of fractional brain water content”; these quantities are directly related but not equivalent. For that reason, the critique by Kauppinen and Knight misinterprets data of prior studies examining lesion water changes in stroke animal models as being inconsistent with our study results in humans, although, upon careful consideration, they are perfectly in line...