Spinal cord structural changes in SPG4: insights from a large cohort using advanced neuroimaging

Area of Science:

• Neuroimaging
• Neurology
• Biomarker Discovery

Background:

• Hereditary spastic paraplegia (HSP) is a neurodegenerative disorder.
• SPG4 is the most common form of autosomal dominant HSP.
• Previous studies focused on spinal cord (SC) structure, not diffusion abnormalities in SPG4.

Purpose of the Study:

• Assess structural and diffusion abnormalities in the cervical and upper thoracic SC in SPG4-HSP patients.
• Correlate imaging findings with demographic and clinical variables.
• Investigate SPG4-HSP using advanced MRI techniques.

Main Methods:

• Diffusion tensor imaging (DTI) of the cervical SC in 40 SPG4-HSP patients and 37 controls.
• Analysis of SC morphology and diffusion properties.
• Correlation of MRI parameters with genotype and disease onset using linear mixed-effects models.

Main Results:

• SPG4-HSP patients showed reduced cervical SC cross-sectional areas.
• Decreased fractional anisotropy (FA) and increased diffusivity were found in key spinal tracts (fasciculus cuneatus, fasciculus gracilis, lateral corticospinal tract, rubrospinal tract).
• FA reduction in the rubrospinal tract correlated with disease onset; gray matter area was smaller in late-onset patients.

Conclusions:

• Evidence of tract-specific axonal degeneration in the cervical SC in SPG4-HSP.
• Diffusion tensor imaging (DTI) shows potential as a biomarker for disease progression.
• Further research with larger cohorts and longitudinal studies is recommended.