Related Experiment Video
Updated: Jul 29, 2025
Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury
Published on: August 14, 2019
Repeatability of neurite orientation dispersion and density imaging in patients with traumatic brain injury
Christina Mueller1, Adam M Goodman1, Rodolphe Nenert1
1Department of Neurology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Background And Purpose:
The aim of this study was to assess the repeatability of neurite orientation dispersion and density imaging in healthy controls (HCs) and traumatic brain injury (TBI).
Methods:
Seventeen HCs and 48 TBI patients were scanned twice over 18 weeks with diffusion imaging. Orientation dispersion (ODI), neurite density (NDI), and the fraction of isotropic diffusion (F-ISO) were quantified in regions of interest (ROIs) from a gray matter, subcortical, and white matter atlas and compared using the coefficient of variation for repeated measures (CVrep ), which quantifies the expected percent change on repeated measurement. We used a modified signed likelihood ratio test (M-SLRT) to compare the CVrep between groups in each ROI while correcting for multiple comparisons.
Results:
NDI exhibited excellent repeatability in both groups; the only group difference was found in the fusiform gyrus, where HCs exhibited better repeatability (M-SLRT = 9.463, p = .0021). ODI also had excellent repeatability in both groups, although repeatability was significantly better in HCs in 16 cortical ROIs (p < .0022) and in the bilateral white matter and bilateral cortex (p < .0027). F-ISO exhibited relatively poor repeatability in both groups, with few group differences.
Conclusion:
Overall, the repeatability of the NDI, ODI, and F-ISO metrics over an 18-week period is acceptable for assessing the effects of behavioral or pharmacological interventions, though caution is advised when assessing F-ISO changes over time.
