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bioRxiv · 10.64898/2026.05.31.728778

Short T1 Fraction as a Marker of Myelin Content: Evidence from Postmortem MRI and Histology

Li, C.·Leitner, D.·Liang, Z.·Yakovishina, V.·Ibrahim, M.·Faustin, A.·Wisniewski, T.·Wadghiri, Y. Z.·Ge, Y.·Zhang, J.
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Abstract

PurposeTo investigate the short-T1 fraction as a potential biomarker of white matter myelin integrity, using myelin histology as ground truth. MethodsMulti-inversion-time MRI data were acquired from four postmortem brain hemisphere specimens from donors with Alzheimers disease on a clinical 3T scanner, and from five dissected tissue blocks containing white matter hyperintensities (WMHs) on a preclinical 3T system. Short-T1 fraction maps were generated using inverse Laplace transform to isolate short-T1 components and were compared with T2-based myelin water imaging metrics through joint T1-T2 correlation analysis. Short-T1 fraction maps from the tissue blocks were further compared with myelin-stained histology. In addition, in vivo short-T1 fraction data were acquired from two elderly volunteers with WMHs to demonstrate translational feasibility. ResultsPostmortem MRI revealed reduced short-T1 fractions in WMHs. T1-T2 correlation analysis showed that the short-T1 fraction was closely associated with the short-T2 (myelin water) component. Strong correlations were observed between short-T1 fractions and optical densities from both Luxol Fast Blue- and myelin basic protein-stained histological sections, supporting the link between the short-T1 signal and myelin content. Consistent findings were also observed in vivo, where significant reductions in short-T1 fractions were detected within WMHs. ConclusionThe short-T1 fraction correlated with myelin content in postmortem brain white matter, supporting its potential as a clinically translatable biomarker of myelin integrity.

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Li, C., Leitner, D., Liang, Z., Yakovishina, V., Ibrahim, M., Faustin, A., Wisniewski, T., Wadghiri, Y. Z., Ge, Y., Zhang, J.. 2026-06-03. Short T1 Fraction as a Marker of Myelin Content: Evidence from Postmortem MRI and Histology. https://doi.org/10.64898/2026.05.31.728778

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