Changes in the thalamus in atypical parkinsonism detected using shape analysis and diffusion tensor imaging

Area of Science:

• Neuroimaging
• Neurodegeneration
• Movement Disorders

Background:

• The thalamus plays a crucial role in cognitive function and sensorimotor integration.
• It is interconnected with the nigrostriatal system and cerebral cortex.
• Understanding thalamic involvement is key in differentiating neurodegenerative diseases.

Purpose of the Study:

• To investigate regional thalamic differences in Parkinson disease (PD), progressive supranuclear palsy (PSP), and corticobasal syndrome (CBS).
• To identify potential imaging biomarkers for distinguishing these conditions.

Main Methods:

• 3T MR imaging (volumetric T1 and diffusion tensor imaging) was performed on patients with PD, PSP, CBS, and healthy volunteers.
• Thalamic nuclear groups were delineated, and apparent diffusion coefficient (ADC) was calculated.
• Thalamic volume, shape, and ADC were compared across all groups.

Main Results:

• PSP and CBS groups showed smaller thalamic volumes compared to PD and control groups.
• Lateral thalamus atrophy was the primary contributor to volume reduction.
• Higher ADC values were observed in PSP compared to PD and controls, particularly in motor thalamic regions.

Conclusions:

• Reduced size and increased ADC disproportionately affect the lateral thalamus in PSP and CBS, suggesting selective neurodegeneration.
• These imaging findings may serve as specific markers for tau-related neurodegeneration.
• The observed thalamic changes differ between PD and tauopathies like PSP and CBS.