Abstract Details

Title Comparing Free-Water Corrected and Uncorrected Single Tensor Diffusion MRI Measures in Individuals with Repetitive Head Impact

Topic Neuro Trauma, Critical Care, and Sports Neurology

Presentation(s) Sports Neurology and Neuro Trauma Posters (7:00 AM-5:00 PM)

Poster/Presentation
Number 010

Objective Compare free-water (f_iso)-corrected and uncorrected diffusion MRI (dMRI) metrics in the white matter (WM) between boxers and healthy controls (HC).

Background F_iso-corrected dMRI-metrics estimated using the bi-tensor model has been shown to improve the precision of conventional single tensor (ST) dMRI measures. F_iso fraction has also been shown to predict and monitor disease progression in various disorders such as schizophrenia, Parkinson’s disease, and Alzheimer’s disease. It is currently unknown, however, whether f_iso-corrected dMRI metrics could better inform the regional WM disorganization in individuals with repetitive head impacts (RHI) such as boxers and help us better understand the neuroanatomical correlations of dMRI measures and neuropsychological scores, as RHI has been shown to induce both topological and regional WM disruptions.

Design/Methods dMRI data were acquired from 12 male boxers (age: 34.33±5.53 years; education: 13.17±1.99 years) and 10 HC (age: 35.5±11.07 years; education: 15±1.56 years) using a 3T Skyra MRI scanner. Two shell dMRI was acquired with the following parameters: 71 diffusion encoding directions each at 2 b-values (b-values: 500s/mm² and 1000s/mm²), spatial resolution=1.5mm³, TE=100ms, multiband factor=3. Both f_iso-corrected and uncorrected dMRI metrics were compared to investigate WM disorganization using nonparametric statistics. A multiple linear regression model was further used to understand the neuroanatomical correlates of f_iso-corrected and uncorrected dMRI metrics with neuropsychological scores and exposure to fighting.

Results Both f_iso-corrected and uncorrected dMRI metrics in boxers showed lower fractional anisotropy (FA) in various WM tracts as compared to HC. Only mean diffusivity (MD) derived using uncorrected ST dMRI-measures showed a negative correlation with age of first competitive fighting. Furthermore, only uncorrected ST-derived radial diffusivity and MD showed negative correlation with processing speed in HC.

Conclusions

Our findings suggest that non-f_iso-corrected dMRI metrics should be interpreted with caution in RHI and that f_iso-correction should be routinely performed to analyze dMRI measures.

Authors/Disclosures
Virendra R. Mishra, PhD (The University of Alabama at Birmingham) PRESENTER	The institution of Prof. Mishra has received research support from Keep Memory Alive Young Scholar Award. The institution of Prof. Mishra has received research support from NINDS/NIA: R01NS117547-01. The institution of Prof. Mishra has received research support from NIGMS: P20GM109025.
Aaron Ritter, MD (Cleveland Clinic)	The institution of Dr. Ritter has received research support from NIH.
Charles Bernick, MD	Dr. Bernick has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Lilly. Dr. Bernick has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Optina. Dr. Bernick has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Eisai. Dr. Bernick has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Corium. Dr. Bernick has stock in Aurora. The institution of Dr. Bernick has received research support from UFC. The institution of Dr. Bernick has received research support from Top Rank Promotions. The institution of Dr. Bernick has received research support from Haymon Boxing.

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