Test-retest reliability of high spatial resolution diffusion tensor and diffusion kurtosis imaging.

Area of Science:

• Neuroimaging
• Radiology
• Biomedical Engineering

Background:

• Concussive traumatic brain injury (cTBI) can cause subtle white matter changes.
• Diffusion MRI techniques like DTI and DKI offer sensitive measures of white matter microstructure.
• Assessing the reliability of advanced diffusion MRI is crucial for clinical application in cTBI.

Purpose of the Study:

• To evaluate the test-retest reliability of high spatial resolution diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI).
• To determine the reproducibility of DTI and DKI metrics in white matter tracts of cTBI patients and healthy controls.

Main Methods:

• Diffusion MRI data acquired on a 3 Tesla Prisma scanner from 3 cTBI patients and 4 controls, scanned twice (0-24 days apart).
• Calculated Coefficients of Variation (CoV) for DTI and DKI parameters at 1.25 mm and 1.75 mm isotropic voxel resolutions.
• Analysis performed on DTI Studio parcellated white matter tracts, including commonly injured orbitofrontal and temporal pole regions.

Main Results:

• Fractional anisotropy demonstrated the highest reliability (mean CoV: 5% at 1.25 mm, 3.5% at 1.75 mm).
• Other DTI metrics showed mean CoV <7.0%, and DKI metrics had mean CoV ≤4.5%.
• Orbitofrontal and temporal pole regions exhibited CoV <3.5% for all parameters, indicating excellent reproducibility in critical areas.

Conclusions:

• High spatial resolution DTI and DKI exhibit good to excellent test-retest reproducibility in cTBI patients and controls with appropriate processing.
• Advanced diffusion MRI techniques are reliable tools for assessing white matter integrity post-cTBI.
• Further technical advancements are necessary to detect the most subtle diffusion abnormalities, particularly at high resolutions.