Tract-Specific Spinal Cord Diffusion Tensor Imaging in Friedreich's Ataxia

Area of Science:

• Neuroimaging
• Neurology
• Biomarkers

Background:

• Spinal cord (SC) damage is a key feature of Friedreich's ataxia (FRDA).
• Previous neuroimaging studies focused on macroscopic SC changes, lacking in vivo microstructural white matter (WM) evaluation.
• This study addresses the gap in assessing SC WM microstructural integrity in FRDA.

Purpose of the Study:

• To evaluate the microstructural integrity of SC WM tracts in FRDA patients using diffusion tensor imaging (DTI).
• To identify potential neuroimaging biomarkers for assessing disease progression and severity in FRDA.

Main Methods:

• A cross-sectional study involving 30 FRDA patients and 30 healthy controls.
• Utilized 3 Tesla MRI with diffusion-weighted imaging (DWI) and an automated analysis pipeline (Spinal Cord Toolbox).
• Measured cross-sectional area (CSA) and DTI parameters (AD, FA, RD, MD) in cervical SC WM tracts (C2-C5).

Main Results:

• FRDA patients exhibited reduced SC cross-sectional area (CSA) across all levels.
• Significant differences in fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) were observed in multiple SC WM tracts between patients and controls.
• FA and RD in several WM tracts, including corticospinal tracts (CST), correlated with Friedreich Ataxia Rating Scale (FARS) scores and disease duration.

Conclusions:

• DTI successfully identified SC WM microstructural abnormalities in FRDA patients.
• These abnormalities correlate with clinical features, with CST FA and DC FA showing strong associations with disease severity and differentiation.
• SC WM microstructure, assessed via DTI, represents a promising neuroimaging biomarker for FRDA research and clinical evaluation.