@inproceedings{f75647f22dba4e8fa054f4c6ad4eaeb6,
title = "Evaluation of inter-site bias and variance in diffusion-weighted MRI",
abstract = "An understanding of the bias and variance of diffusion weighted magnetic resonance imaging (DW-MRI) acquisitions across scanners, study sites, or over time is essential for the incorporation of multiple data sources into a single clinical study. Studies that combine samples from various sites may be introducing confounding factors due to site-specific artifacts and patterns. Differences in bias and variance across sites may render the scans incomparable, and, without correction, inferences obtained from these data may be misleading. We present an analysis of the bias and variance of scans of the same subjects across different sites and evaluate their impact on statistical analyses. In previous work, we presented a simulation extrapolation (SIMEX) technique for bias estimation as well as a wild bootstrap technique for variance estimation in metrics obtained from a Q-ball imaging (QBI) reconstruction of empirical high angular resolution diffusion imaging (HARDI) data. We now apply those techniques to data acquired from 5 healthy volunteers on 3 independent scanners under closely matched acquisition protocols. The bias and variance of GFA measurements were estimated on a voxel-wise basis for each scan and compared across study sites to identify site-specific differences. Further, we provide model recommendations that can be used to determine the extent of the impact of bias and variance as well as aspects of the analysis to account for these differences. We include a decision tree to help researchers determine if model adjustments are necessary based on the bias and variance results.",
keywords = "HARDI, Q-ball, SIMEX, bias correction, bootstrap, multi-site",
author = "Hainline, {Allison E.} and Vishwesh Nath and Prasanna Parvathaneni and Justin Blaber and Baxter Rogers and Allen Newton and Jeffrey Luci and Heidi Edmonson and Hakmook Kang and Landman, {Bennett A.}",
note = "Funding Information: This work was supported by R01EB017230 & Grant UL1 RR024975-01 & Grant 2 UL1 TR000445-06 and Advanced Computing center for Research and Education (ACCRE). The material presented are the views of the authors listed and do not necessarily reflect the views of the sponsoring entities. Publisher Copyright: {\textcopyright} COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.; Medical Imaging 2018: Image Processing ; Conference date: 11-02-2018 Through 13-02-2018",
year = "2018",
doi = "10.1117/12.2293735",
language = "English (US)",
series = "Progress in Biomedical Optics and Imaging - Proceedings of SPIE",
publisher = "SPIE",
editor = "Angelini, {Elsa D.} and Angelini, {Elsa D.} and Landman, {Bennett A.}",
booktitle = "Medical Imaging 2018",
}