Scan-rescan repeatability of axonal imaging metrics using high-gradient diffusion MRI and statistical implications for study design
Year: 2021
Type: article
Abstract: Axon diameter mapping using diffusion MRI in the living human brain has attracted growing interests with the increasing availability of high gradient strength MRI systems. A systematic assessment of the consistency of axon diameter estimates within and between individuals is needed to gain a comprehensive understanding of how such methods extend to quantifying differences in axon diameter index between groups and facilitate the design of neurobiological studies using such measures. We examined the scan-rescan repeatability of axon diameter index estimation based on the spherical mean technique (SMT) approach using diffusion MRI data acquired with gradient strengths up to 300 mT/m on a 3T Connectom system in 7 healthy volunteers. We performed statistical power analyses using data acquired with the same protocol in a larger cohort consisting of 15 healthy adults to investigate the implications for study design. Results revealed a high degree of repeatability in voxel-wise restricted volume fraction estimates and tract-wise estimates of axon diameter index derived from high-gradient diffusion MRI data. On the region of interest (ROI) level, across white matter tracts in the whole brain, the Pearson's correlation coefficient of the axon diameter index estimated between scan and rescan experiments was r = 0.72 with an absolute deviation of 0.18 μm. For an anticipated 10% effect size in studies of axon diameter index, most white matter regions required a sample size of less than 15 people to observe a measurable difference between groups using an ROI-based approach. To facilitate the use of high-gradient strength diffusion MRI data for neuroscientific studies of axonal microstructure, the comprehensive multi-gradient strength, multi-diffusion time data used in this work will be made publicly available, in support of open science and increasing the accessibility of such data to the greater scientific community.
Source: NeuroImage
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,300
Funders: National Multiple Sclerosis Society, Conrad N. Hilton Foundation, American Heart Association, Massachusetts General Hospital, Multiple Sclerosis Society, National Institutes of Health, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, National Institute of Biomedical Imaging and Bioengineering, National Center for Research Resources
Awards: G17320278, Characterizing axonal damage in multiple sclerosis using TractCaliber MRI, G2227408383, G2483948867, Parallel Excitation Methods for High Field MRI, Modeling TMS-induced Cortical Network Activity, Connectome 2.0: Developing the next generation human MRI scanner for bridging studies of the micro-, meso- and macro-connectome, G393103480, The Human Connectome Project (HCP), TractCaliber MRI for Characterizing Axonal Damage in Ischemic Stroke, G5557224331, Computeserver Structural &Functional Image Analysis, G7066352928, Center for Functional Imaging Technologies, Disconnection as a model for cognitive dysfunction in multiple sclerosis, A Storage Area Network for Structural and Functional Image Analysis, G9000054376, Toward a Validated in Vivo Imaging Marker of Axonal Damage Predictive of Progressive Disability in Multiple Sclerosis, Center for Mesoscale Mapping, Silicon Graphics Prism Extreme 128P/1TB, G984581029
OpenAlex ID: W3181061920