Subcortical shape alterations in spinocerebellar ataxia type 2: a longitudinal MRI-based analysis

Area of Science:

• Neuroimaging
• Neurodegenerative Diseases
• Quantitative Anatomy

Background:

• Spinocerebellar ataxia type 2 (SCA2) is a progressive neurodegenerative disorder affecting both cerebellar and extracerebellar regions.
• Previous MRI studies identified gray matter changes, but subcortical shape alterations remain underexplored.

Purpose of the Study:

• To investigate cross-sectional and longitudinal subcortical gray matter shape changes in genetically confirmed SCA2 patients.
• Utilize a vertex-based morphometric approach to characterize detailed morphological alterations.

Main Methods:

• Acquired T1-weighted MRI data from SCA2 patients and healthy controls from OpenNeuro.
• Performed vertex-wise shape analyses and eTIV-normalized volumetric analyses on baseline and follow-up scans (approx. 3.5 years interval).

Main Results:

• SCA2 patients showed outward shape deformations in the hippocampus, caudate nucleus, and putamen compared to controls.
• Longitudinal analysis revealed progressive shape changes in the caudate nucleus, pallidum, and putamen in SCA2.
• Volumetric analysis indicated reduced brainstem and thalamic volumes, with greater volume loss in the pallidum and hippocampi over time in SCA2 patients.

Conclusions:

• Vertex-based shape analysis reveals progressive, region-specific subcortical abnormalities in SCA2.
• Shape analysis captures alterations not fully detected by volumetric methods, providing complementary insights.
• These findings enhance the characterization of subcortical involvement and disease progression in SCA2.