TY - JOUR
T1 - Mapping myelin in white matter with T1-weighted/T2-weighted maps
T2 - discrepancy with histology and other myelin MRI measures
AU - Sandrone, Stefano
AU - Aiello, Marco
AU - Cavaliere, Carlo
AU - Thiebaut de Schotten, Michel
AU - Reimann, Katja
AU - Troakes, Claire
AU - Bodi, Istvan
AU - Lacerda, Luis
AU - Monti, Serena
AU - Murphy, Declan
AU - Geyer, Stefan
AU - Catani, Marco
AU - Dell’Acqua, Flavio
N1 - Funding Information:
Stefano Sandrone was funded by the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London. Marco Catani is the recipient of a Wellcome Trust Investigator Award (103759/Z/14/Z). The London Neurodegenerative Diseases Brain Bank receives funding from the MRC and as part of the Brains for Dementia Research programme, jointly funded by Alzheimer’s Research UK and Alzheimer’s Society. Michel Thiebaut de Schotten is funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 818521). Flavio Dell’Acqua is funded by the Sackler Institute for Translational Neurodevelopment. Michel Thiebaut de Schotten would like to thank the University of Bordeaux−s IdEx “Investments for the Future” program RRI “IMPACT,” which received financial support from the French government. We thank the staff of the Clinical Neuropathology Department at King’s College Hospital for diagnostic and technical assistance, and we also thank the donors and their families.
Publisher Copyright:
© 2023, The Author(s).
PY - 2023/3
Y1 - 2023/3
N2 - The ratio of T1-weighted/T2-weighted magnetic resonance images (T1w/T2w MRI) has been successfully applied at the cortical level since 2011 and is now one of the most used myelin mapping methods. However, no reports have explored the histological validity of T1w/T2w myelin mapping in white matter. Here we compare T1w/T2w with ex vivo postmortem histology and in vivo MRI methods, namely quantitative susceptibility mapping (QSM) and multi-echo T2 myelin water fraction (MWF) mapping techniques. We report a discrepancy between T1w/T2w myelin maps of the human corpus callosum and the histology and analyse the putative causes behind such discrepancy. T1w/T2w does not positively correlate with Luxol Fast Blue (LFB)-Optical Density but shows a weak to moderate, yet significant, negative correlation. On the contrary, MWF is strongly and positively correlated with LFB, whereas T1w/T2w and MWF maps are weakly negatively correlated. The discrepancy between T1w/T2w MRI maps, MWF and histological myelin maps suggests caution in using T1w/T2w as a white matter mapping method at the callosal level. While T1w/T2w imaging may correlate with myelin content at the cortical level, it is not a specific method to map myelin density in white matter.
AB - The ratio of T1-weighted/T2-weighted magnetic resonance images (T1w/T2w MRI) has been successfully applied at the cortical level since 2011 and is now one of the most used myelin mapping methods. However, no reports have explored the histological validity of T1w/T2w myelin mapping in white matter. Here we compare T1w/T2w with ex vivo postmortem histology and in vivo MRI methods, namely quantitative susceptibility mapping (QSM) and multi-echo T2 myelin water fraction (MWF) mapping techniques. We report a discrepancy between T1w/T2w myelin maps of the human corpus callosum and the histology and analyse the putative causes behind such discrepancy. T1w/T2w does not positively correlate with Luxol Fast Blue (LFB)-Optical Density but shows a weak to moderate, yet significant, negative correlation. On the contrary, MWF is strongly and positively correlated with LFB, whereas T1w/T2w and MWF maps are weakly negatively correlated. The discrepancy between T1w/T2w MRI maps, MWF and histological myelin maps suggests caution in using T1w/T2w as a white matter mapping method at the callosal level. While T1w/T2w imaging may correlate with myelin content at the cortical level, it is not a specific method to map myelin density in white matter.
KW - Corpus callosum
KW - Myelin mapping
KW - Myelin water fraction
KW - Neuroanatomy
KW - Neuroimaging
KW - Quantitative susceptibility mapping
KW - Validation
UR - http://www.scopus.com/inward/record.url?scp=85146648100&partnerID=8YFLogxK
U2 - 10.1007/s00429-022-02600-z
DO - 10.1007/s00429-022-02600-z
M3 - Article
C2 - 36692695
AN - SCOPUS:85146648100
SN - 1863-2653
VL - 228
SP - 525
EP - 535
JO - Brain Structure and Function
JF - Brain Structure and Function
IS - 2
ER -