---
title: "T2 relaxometry validation of myelin water fraction using TSE and GRASE in ex vivo human brains"
id: "biorxiv-19-t2-relaxometry-for-myelin-water-fraction-an-ex-vivo-brain-imaging-study"
canonical_url: "https://medichelpline.com/clinical-feed/biorxiv-19-t2-relaxometry-for-myelin-water-fraction-an-ex-vivo-brain-imaging-study"
content_type: "clinical_feed_article"
specialty: "Radiology"
source_name: "bioRxiv (Biomedical Preprints)"
source_url: "https://www.biorxiv.org/content/10.64898/2026.09.14.751605v1?rss=1"
published_at: "2026-09-21T12:00:00.000Z"
evidence_level: "Verified Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# T2 relaxometry validation of myelin water fraction using TSE and GRASE in ex vivo human brains
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/biorxiv-19-t2-relaxometry-for-myelin-water-fraction-an-ex-vivo-brain-imaging-study
- **Specialty:** [Radiology](https://medichelpline.com/clinical-feed/radiology.md)
- **Primary Source:** bioRxiv (Biomedical Preprints)
- **Source URL:** [Original Journal Publication](https://www.biorxiv.org/content/10.64898/2026.09.14.751605v1?rss=1)
- **Published At:** 2026-09-21T12:00:00.000Z
- **Evidence Rating:** Verified Feed
## Executive GIST (TL;DR)
- The study investigates **myelin water imaging** using T2 relaxometry to estimate the **myelin water fraction (MWF)** in formaldehyde-fixed postmortem human brain hemispheres. - Two MRI sequence families were compared: **turbo spin echo (TSE)** and **gradient-and-spin-echo (GRASE)**, with the goal of validating sequences suitable for postmortem MWF assessment. - Forty postmortem human brain hemispheres were scanned with both **TSE** and **GRASE** sequences, providing a dataset for direct comparison. - Data were analyzed using a non-parametric multicomponent **T2 relaxometry** reconstruction framework applied consistently across both sequence types to enable comparison of derived measures at voxel and regional levels. - For GRASE, maps from a full **32-echo** reconstruction were compared with a truncated **14-echo** reconstruction to assess effects of echo sampling on derived measures. - The study emphasizes the potential of postmortem imaging to validate MRI-derived MWF against neuropathological gold standards, though direct pathology comparison details were not reported in the provided source text. - Specifics on imaging parameters, quantitative results, statistical analyses, regional outcomes, correlations with histopathology, and final conclusions were not reported in the excerpt provided and therefore cannot be inferred.
## Clinical Analysis & Structured Key Points
T2 relaxometry for myelin water fraction: an ex vivo brain imaging study | bioRxiv Skip to main content New Results T 2 relaxometry for myelin water fraction: an ex vivo brain imaging study View ORCID Profile Liana Sanches , Narges Taghizadehsalehabad , View ORCID Profile Roqaie Moqadam , View ORCID Profile Walter Adame-Gonzalez , View ORCID Profile Zaki Alasmar , View ORCID Profile Dominique Mirault , View ORCID Profile Gian Franco Piredda , View ORCID Profile Gustavo Turecki , View ORCID Profile Josefina Maranzano , View ORCID Profile Naguib Mechawar , The CIMA-Q group , View ORCID Profile Mallar Chakravarty , View ORCID Profile Mahsa Dadar , View ORCID Profile Yashar Zeighami doi: https://doi.org/10.64898/2026.09.14.751605 Liana Sanches 1 Douglas Mental Health University Institute; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Liana Sanches For correspondence: liana.guerrasanches{at}mail.mcgill.ca Narges Taghizadehsalehabad 2 Douglas Mental Health University Institute; Integrated Program in Neuroscience, McGill University; Find this author on Google Scholar Find this author on PubMed Search for this author on this site Roqaie Moqadam 3 Douglas Mental Health University Institute; Department of Medicine, Université de Montréal; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Roqaie Moqadam Walter Adame-Gonzalez 4 Douglas Mental Health University Institute; Integrated Program in Neuroscience, McGill University.; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Walter Adame-Gonzalez Zaki Alasmar 4 Douglas Mental Health University Institute; Integrated Program in Neuroscience, McGill University.; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Zaki Alasmar Dominique Mirault 1 Douglas Mental Health University Institute; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Dominique Mirault Gian Franco Piredda 5 Swiss Innovation Hub, Siemens Healthineers International AG, Lausanne, Switzerland; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Gian Franco Piredda Gustavo Turecki 4 Douglas Mental Health University Institute; Integrated Program in Neuroscience, McGill University.; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Gustavo Turecki Josefina Maranzano 6 Department of Anatomy, University of Quebec in Trois-Rivieres; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Josefina Maranzano Naguib Mechawar 7 Douglas Mental Health University Institute; Department of Psychiatry, McGill University. Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Naguib Mechawar Mallar Chakravarty 7 Douglas Mental Health University Institute; Department of Psychiatry, McGill University. Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Mallar Chakravarty Mahsa Dadar 7 Douglas Mental Health University Institute; Department of Psychiatry, McGill University. Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Mahsa Dadar Yashar Zeighami 7 Douglas Mental Health University Institute; Department of Psychiatry, McGill University. Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Yashar Zeighami Abstract Info/History Metrics Preview PDF Abstract Abstract Introduction: Myelin water imaging provides a non-invasive approach for indirectly investigating myelin content of the brain by magnetic resonance Imaging (MRI). Myelin water fraction (MWF) reflects the fraction of water signal associated with water trapped between myelin layers. Postmortem imaging provides a unique opportunity to validate MWF metrics against gold-standard postmortem neuropathology. However, there is a need for validated sequences that would be applicable in postmortem settings. In this study, we validated and compared the applicability of turbo spin echo (TSE) and gradient-and-spin-echo (GRASE) techniques for myelin water imaging in formaldehyde fixed postmortem human brains. Methods: 40 postmortem human brain hemispheres were scanned with TSE and GRASE sequences. Acquired data were reconstructed using a non-parametric multicomponent T2 relaxometry approach using a consistent framework to support comparison between GRASE- and TSE-derived measures. Agreement between derived measures was quantified at both voxel and regional level. Maps derived from the full 32-echo GRASE reconstruction were compared against a truncated 14-echo reconstruction to examine the contribution of the longer echoes to the derived maps. Finally, a random forest regression model was trained based on TSE data to predict the GRASE-derived MWF maps. Results: Both sequences provided robust multicomponent T2 characterization across the brain, and the derived measures showed anatomical patterns consistent with expected differences across tissue types. TSE and GRASE derived maps had moderate to strong agreement at voxel (0.41 0.98, pFDR < 0.001). The nonlinear random forest regression model trained on TSE maps was able to accurately reproduce the MWF maps derived from GRASE (r = 0.91, RMSE = 8.87). Discussion: TSE and GRASE32 capture strongly related multicomponent T₂ information in fixed postmortem human brain tissue, but with systematic and tissue-dependent quantitative differences across derived measures. These differences suggest that direct interchangeability should not be assumed and that cross-sequence mapping or calibration is required when quantitative equivalence is desired. Competing Interest Statement The authors have declared no competing interest. Funder Information Declared Natural Sciences and Engineering Research Council of Canada (NSERC) , RGPIN-2023-04038 , RGPIN-2023-04218 Canadian Institutes of Health Research (CIHR) , 191303 , 198104 , 213169 , 195671 , 330750 , 379799 Fonds de Recherche du Québec - Santé, https://ror.org/02eqrsj93 , 330750 , 379799 Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license . Back to top Previous Next Posted September 21, 2026. Download PDF Email Thank you for your interest in spreading the word about bioRxiv. NOTE: Your email address is requested solely to identify you as the sender of this article. Your Email * Your Name * Send To * Enter multiple addresses on separate lines or separate them with commas. 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Share T 2 relaxometry for myelin water fraction: an ex vivo brain imaging study Liana Sanches , Narges Taghizadehsalehabad , Roqaie Moqadam , Walter Adame-Gonzalez , Zaki Alasmar , Dominique Mirault , Gian Franco Piredda , Gustavo Turecki , Josefina Maranzano , Naguib Mechawar , The CIMA-Q group , Mallar Chakravarty , Mahsa Dadar , Yashar Zeighami bioRxiv 2026.09.14.751605; doi: https://doi.org/10.64898/2026.09.14.751605 Share This Article: Copy Citation Tools T 2 relaxometry for myelin water fraction: an ex vivo brain imaging study Liana Sanches , Narges Taghizadehsalehabad , Roqaie Moqadam , Walter Adame-Gonzalez , Zaki Alasmar , Dominique Mirault , Gian Franco Piredda , Gustavo Turecki , Josefina Maranzano , Naguib Mechawar , The CIMA-Q group , Mallar Chakravarty , Mahsa Dadar , Yashar Zeighami bioRxiv 2026.09.14.751605; doi: https://doi.org/10.64898/2026.09.14.751605 Citation Manager Formats BibTeX Bookends EasyBib EndNote (tagged) EndNote 8 (xml) Medlars Mendeley Papers RefWorks Tagged Ref Manager RIS Zotero Tweet Widget Facebook Like Google Plus One Subject Areas All Articles Animal Behavior and Cognition (8015) Biochemistry (18744) Bioengineering (14890) Bioinformatics (44453) Biophysics (22610) Cancer Biology (19728) Cell Biology (26906) Clinical Trials (138) Developmental Biology (13970) Ecology (21008) Epidemiology (2067) Evolutionary Biology (25457) Genetics (16171) Genomics (23513) Immunology (18717) Microbiology (42520) Molecular Biology (18064) Neuroscience (93479) Paleontology (700) Pathology (2982) Pharmacology and Toxicology (5100) Physiology (8116) Plant Biology (16000) Scientific Communication and Education (2095) Synthetic Biology (4560) Systems Biology (10237) Zoology (2391)
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