RT Journal Article
SR Electronic
T1 Free water in white matter differentiates MCI and AD from control subjects
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 537092
DO 10.1101/537092
A1 Matthieu Dumont
A1 Maggie Roy
A1 Pierre-Marc Jodoin
A1 Felix C. Morency
A1 Jean-Christophe Houde
A1 Zhiyong Xie
A1 Cici Bauer
A1 Tarek A. Samad
A1 Koene R. A. Van Dijk
A1 James A. Goodman
A1 Maxime Descoteaux
YR 2019
UL http://biorxiv.org/content/early/2019/01/31/537092.abstract
AB Recent evidence show that neuroinflammation plays a role in many neurological diseases including mild cognitive impairment (MCI) and Alzheimer’s disease (AD), and that free water (FW) modeling from clinically acquired diffusion MRI (DTI-like acquisitions) can be sensitive to this phenomenon. This FW index measures the fraction of the diffusion signal explained by isotropically unconstrained water, as estimated from a bi-tensor model. In this study, we developed a simple FW processing pipeline that uses a safe white matter (WM) mask without gray matter (GM)/CSF partial volume contamination (WMsafe) near ventricles and sulci. We investigated if FW inside the WMsafe mask, including and excluding areas of white matter damage such as white matter hyperintensities (WMHs) as shown on T2 FLAIR, computed across the whole white matter could be indicative of diagnostic grouping along the AD continuum.After careful quality control, 81 cognitively normal controls (NC), 103 subjects with MCI and 42 with AD were selected from the ADNIGO and ADNI2 databases. We show that MCI and AD have significantly higher FW measures even after removing all partial volume contamination. We also show, for the first time, that when WMHs are removed from the masks, the significant results are maintained, which demonstrates that the FW measures are not just a byproduct of WMHs. Our new and simple FW measures can be used to increase our understanding of the role of inflammation-associated edema in AD and may aid in the differentiation of healthy subjects from MCI and AD patients.