PURPOSE: Magnetic resonance relaxation times of most tissues are expected to depend on temperature, which can impact findings in postmortem magnetic resonance imaging or when using magnetic resonance imaging for relaxation-based thermometry. The purpose of this study was to investigate the exact temperature dependency of the relaxation times T(1), T(2), T(2) *, and the magnetization transfer ratio in different structures of the human brain. METHODS: To prevent fixation and autolysis effects, this study was performed with fresh postmortem brain tissues. Following autopsy, coronal brain slices from five deceased subjects were subjected to relaxometry at 3T in a temperature range between 4°C and 37°C. Heating of the tissue was achieved by flushing the vacuum packed brain slices with water at a predefined temperature. RESULTS: T1 showed a linear dependency on temperature with the highest temperature coefficient in the cortex (17.4 ms/°C) and the lowest in the white matter (3.4 ms/°C). T(2) did not depend on temperature. T(2) * and magnetization transfer ratio scaled with temperature only in deep gray matter. CONCLUSION: The temperature coefficient for T(1) is higher than expected from previous reports and varies across brain structures. The coefficients obtained in this study can serve as reference for thermometry or for correcting quantitative postmortem magnetic resonance imaging.
PURPOSE: Magnetic resonance relaxation times of most tissues are expected to depend on temperature, which can impact findings in postmortem magnetic resonance imaging or when using magnetic resonance imaging for relaxation-based thermometry. The purpose of this study was to investigate the exact temperature dependency of the relaxation times T(1), T(2), T(2) *, and the magnetization transfer ratio in different structures of the human brain. METHODS: To prevent fixation and autolysis effects, this study was performed with fresh postmortem brain tissues. Following autopsy, coronal brain slices from five deceased subjects were subjected to relaxometry at 3T in a temperature range between 4°C and 37°C. Heating of the tissue was achieved by flushing the vacuum packed brain slices with water at a predefined temperature. RESULTS: T1 showed a linear dependency on temperature with the highest temperature coefficient in the cortex (17.4 ms/°C) and the lowest in the white matter (3.4 ms/°C). T(2) did not depend on temperature. T(2) * and magnetization transfer ratio scaled with temperature only in deep gray matter. CONCLUSION: The temperature coefficient for T(1) is higher than expected from previous reports and varies across brain structures. The coefficients obtained in this study can serve as reference for thermometry or for correcting quantitative postmortem magnetic resonance imaging.
Authors: Bridgette Webb; Martin Manninger; Marlene Leoni; Thomas Widek; Martin Dobrovnik; Daniel Scherr; Rudolf Stollberger; Thorsten Schwark Journal: Int J Legal Med Date: 2019-12-18 Impact factor: 2.686
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Authors: Matthew J Betts; Evgeniya Kirilina; Maria C G Otaduy; Dimo Ivanov; Julio Acosta-Cabronero; Martina F Callaghan; Christian Lambert; Arturo Cardenas-Blanco; Kerrin Pine; Luca Passamonti; Clare Loane; Max C Keuken; Paula Trujillo; Falk Lüsebrink; Hendrik Mattern; Kathy Y Liu; Nikos Priovoulos; Klaus Fliessbach; Martin J Dahl; Anne Maaß; Christopher F Madelung; David Meder; Alexander J Ehrenberg; Oliver Speck; Nikolaus Weiskopf; Raymond Dolan; Ben Inglis; Duygu Tosun; Markus Morawski; Fabio A Zucca; Hartwig R Siebner; Mara Mather; Kamil Uludag; Helmut Heinsen; Benedikt A Poser; Robert Howard; Luigi Zecca; James B Rowe; Lea T Grinberg; Heidi I L Jacobs; Emrah Düzel; Dorothea Hämmerer Journal: Brain Date: 2019-09-01 Impact factor: 13.501