Regional Outlier Analysis of Longitudinal MAP-MRI Changes following Mild Traumatic Brain Injury

Motivation: Cross sectional radiological assessments of mild traumatic brain injury (mTBI) often produce conflicting findings with poor correlation to clinical outcomes. Goal(s): Mean apparent propagator MRI (MAP-MRI) in a pilot longitudinal study is proposed to probe complex alterations in tissue microstructure following mTBI. Approach: Quantitative region of interest analysis of MAP-MRI and DTI-derived metrics was performed in a pilot cohort of mTBI patients at four timepoints up to 90 days following injury. Results: Several MAP-MRI derived parameters had increased intersession variability in white matter tracts and deep gray matter nuclei relative to healthy controls during the 90-day period of observation. Impact: Longitudinal monitoring of changes in MAP-MRI metrics may provide a more comprehensive means to study pathological alterations that evolve at multiple timepoints in mTBI, where current image-based biomarkers lack the sensitivity and specificity to predict outcome.