Tissue magnetic susceptibility mapping as a marker of tau pathology in Alzheimer's disease

• Published in: NeuroImage (Orlando, Fla.) Vol. 159; pp. 334 - 345
• Main Authors: O'Callaghan, J., Holmes, H., Powell, N., Wells, J.A., Ismail, O., Harrison, I.F., Siow, B., Johnson, R., Ahmed, Z., Fisher, A., Meftah, S., O'Neill, M.J., Murray, T.K., Collins, E.C., Shmueli, K., Lythgoe, M.F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2017; Elsevier Limited; Academic Press
• Subjects: Alzheimer Disease - pathology; Alzheimer's disease; Animals; Brain; Brain - pathology; Brain mapping; Brain Mapping - methods; Compensation; Corpus callosum; Female; Image Processing, Computer-Assisted; Inflammation; Iron; Magnetic resonance imaging; Magnetic susceptibility; Mice; Mice, Transgenic; Myelin; Neostriatum; Neurodegenerative diseases; Neurofibrillary tangles; Neurofibrillary Tangles - pathology; Neurological diseases; NMR; Nuclear magnetic resonance; Oxidative stress; Pathology; Substantia alba; Substantia grisea; Tau protein; Tauopathies - pathology; Thalamus; United Kingdom > UK; United States > US
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2017.08.003

Alzheimer's disease is connected to a number of other neurodegenerative conditions, known collectively as ‘tauopathies’, by the presence of aggregated tau protein in the brain. Neuroinflammation and oxidative stress in AD are associated with tau pathology and both the breakdown of axonal sheaths in white matter tracts and excess iron accumulation grey matter brain regions. Despite the identification of myelin and iron concentration as major sources of contrast in quantitative susceptibility maps of the brain, the sensitivity of this technique to tau pathology has yet to be explored. In this study, we perform Quantitative Susceptibility Mapping (QSM) and T2* mapping in the rTg4510, a mouse model of tauopathy, both in vivo and ex vivo. Significant correlations were observed between histological measures of myelin content and both mean regional magnetic susceptibility and T2* values. These results suggest that magnetic susceptibility is sensitive to tissue myelin concentrations across different regions of the brain. Differences in magnetic susceptibility were detected in the corpus callosum, striatum, hippocampus and thalamus of the rTg4510 mice relative to wild type controls. The concentration of neurofibrillary tangles was found to be low to intermediate in these brain regions indicating that QSM may be a useful biomarker for early stage detection of tau pathology in neurodegenerative diseases. •The rTg4510 is a mouse model of tauopathy.•We applied QSM and T2* Mapping MRI techniques to the rTg4510 in vivo and ex vivo.•QSM demonstrated sensitivity to regions of low and intermediate tau burden.•QSM may hold potential as a non-invasive early biomarker of tau pathology.