Petr Dusek1,2, Vince Istvan Madai3, Till Huelnhagen4, Erik Bahn5, Radoslav Matej6,7, Jan Sobesky3,8, Thoralf Niendorf4,8, Julio Acosta-Cabronero9,10, Jens Wuerfel11,12,13. 1. Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Praha, Czech Republic. 2. Department of Radiology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Praha, Czech Republic. 3. Department of Neurology and Center for Stroke Research Berlin (CSB), Charité-Universitaetsmedizin, Berlin, Germany. 4. Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany. 5. Institute of Neuropathology, University Medicine Göttingen, Göttingen, Germany. 6. Department of Pathology and Molecular Medicine, Thomayer Hospital, Praha, Czech Republic. 7. Department of Pathology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Praha, Czech Republic. 8. Experimental and Clinical Research Center (ECRC), Charité-Universitaetsmedizin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany. 9. Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom. 10. German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany. 11. NeuroCure Clinical Research Center, Charité-Universitaetsmedizin, Berlin, Germany. 12. Medical Imaging Analysis Center AG, Basel, Switzerland. 13. Department of Biomedical Engineering, University Basel, Switzerland.
Abstract
PURPOSE: The quality and precision of post-mortem MRI microscopy may vary depending on the embedding medium used. To investigate this, our study evaluated the impact of 5 widely used media on: (1) image quality, (2) contrast of high spatial resolution gradient-echo (T1 and T2 * -weighted) MR images, (3) effective transverse relaxation rate (R2 * ), and (4) quantitative susceptibility measurements (QSM) of post-mortem brain specimens. METHODS: Five formaldehyde-fixed brain slices were scanned using 7.0T MRI in: (1) formaldehyde solution (formalin), (2) phosphate-buffered saline (PBS), (3) deuterium oxide (D2 O), (4) perfluoropolyether (Galden), and (5) agarose gel. SNR and contrast-to-noise ratii (SNR/CNR) were calculated for cortex/white matter (WM) and basal ganglia/WM regions. In addition, median R2 * and QSM values were extracted from caudate nucleus, putamen, globus pallidus, WM, and cortical regions. RESULTS: PBS, Galden, and agarose returned higher SNR/CNR compared to formalin and D2 O. Formalin fixation, and its use as embedding medium for scanning, increased tissue R2 * . Imaging with agarose, D2 O, and Galden returned lower R2 * values than PBS (and formalin). No major QSM offsets were observed, although spatial variance was increased (with respect to R2 * behaviors) for formalin and agarose. CONCLUSIONS: Embedding media affect gradient-echo image quality, R2 * , and QSM in differing ways. In this study, PBS embedding was identified as the most stable experimental setup, although by a small margin. Agarose and Galden were preferred to formalin or D2 O embedding. Formalin significantly increased R2 * causing noisier data and increased QSM variance.
PURPOSE: The quality and precision of post-mortem MRI microscopy may vary depending on the embedding medium used. To investigate this, our study evaluated the impact of 5 widely used media on: (1) image quality, (2) contrast of high spatial resolution gradient-echo (T1 and T2 * -weighted) MR images, (3) effective transverse relaxation rate (R2 * ), and (4) quantitative susceptibility measurements (QSM) of post-mortem brain specimens. METHODS: Five formaldehyde-fixed brain slices were scanned using 7.0T MRI in: (1) formaldehyde solution (formalin), (2) phosphate-buffered saline (PBS), (3) deuterium oxide (D2 O), (4) perfluoropolyether (Galden), and (5) agarose gel. SNR and contrast-to-noise ratii (SNR/CNR) were calculated for cortex/white matter (WM) and basal ganglia/WM regions. In addition, median R2 * and QSM values were extracted from caudate nucleus, putamen, globus pallidus, WM, and cortical regions. RESULTS:PBS, Galden, and agarose returned higher SNR/CNR compared to formalin and D2 O. Formalin fixation, and its use as embedding medium for scanning, increased tissue R2 * . Imaging with agarose, D2 O, and Galden returned lower R2 * values than PBS (and formalin). No major QSM offsets were observed, although spatial variance was increased (with respect to R2 * behaviors) for formalin and agarose. CONCLUSIONS: Embedding media affect gradient-echo image quality, R2 * , and QSM in differing ways. In this study, PBS embedding was identified as the most stable experimental setup, although by a small margin. Agarose and Galden were preferred to formalin or D2 O embedding. Formalin significantly increased R2 * causing noisier data and increased QSM variance.
Authors: Benjamin C Tendler; Feng Qi; Sean Foxley; Menuka Pallebage-Gamarallage; Ricarda A L Menke; Olaf Ansorge; Samuel A Hurley; Karla L Miller Journal: Hum Brain Mapp Date: 2021-09-20 Impact factor: 5.399
Authors: Ramin Jafari; Stefanie J Hectors; Anne K Koehne de González; Pascal Spincemaille; Martin R Prince; Gary M Brittenham; Yi Wang Journal: NMR Biomed Date: 2020-09-22 Impact factor: 4.044
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