Longitudinal MAP-MRI-based Assessment of Tissue Microstructural Alterations in Acute mTBI

Area of Science:

• Neuroimaging
• Radiology
• Biophysics

Background:

• Mild traumatic brain injury (mTBI) is a common injury often undetectable by conventional imaging.
• Diffusion MRI (dMRI) shows promise for detecting subtle microstructural changes post-mTBI.

Purpose of the Study:

• To evaluate the efficacy of mean apparent propagator MRI (MAP-MRI), a sophisticated dMRI technique, in detecting mTBI-related sequelae.
• To assess if MAP-MRI can reveal microstructural alterations in patients with acute mTBI.

Main Methods:

• Analysis of dMRI data from 417 participants (143 controls, 274 mTBI patients) using the MAP-MRI framework.
• Quantification of microstructural parameters like propagator anisotropy (PA) and Non-Gaussianity (NG) across four visits.
• Correlation of dMRI metrics with clinical assessments including post-concussive symptoms (RPQ-3, RPQ-13) and postural stability (BESS).

Main Results:

• MAP-MRI parameters showed minimal variation and no significant longitudinal differences between mTBI patients and controls.
• mTBI patients exhibited increased symptom scores (RPQ-3, RPQ-13) but not postural instability (BESS) acutely.
• Significant correlations were found between MAP-MRI metrics in specific brain regions and BESS scores.

Conclusions:

• A novel quantitative image processing pipeline for longitudinal dMRI data was developed and validated.
• The study indicates that acute mTBI (GCS≥13) may not cause microstructural damage detectable by current dMRI methods.
• Further advancements in diffusion sensitization and analysis techniques may be necessary for detecting subtle mTBI alterations.