Transcallosal diffusion tensor abnormalities in predominant gait disorder parkinsonism

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• No prior Diffusion Tensor Imaging (DTI) studies have compared Parkinson's disease (PD) with postural instability and gait disorder (PIGD) parkinsonism.
• DTI offers a novel approach to investigate white matter integrity in neurodegenerative disorders.

Purpose of the Study:

• To investigate differential brain region involvement in PIGD versus PD and controls using DTI and 2-region tractography.
• To identify specific neural network alterations associated with PIGD using advanced neuroimaging techniques.

Main Methods:

• A case-control study utilizing 3 Tesla MRI with DTI.
• Manual region of interest (ROI) placement to assess fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values in motor tracts.
• Correlation of DTI metrics with the Tinetti score for gait and balance assessment.

Main Results:

• PIGD subjects exhibited greater ADC abnormalities in extrapyramidal, pyramidal, and transcallosal motor systems compared to controls.
• Fractional anisotropy (FA) and ADC values in the corpus callosum body significantly differentiated PIGD from PD.
• Lower FA and higher ADC in the corpus callosum body were associated with lower Tinetti scores in PIGD patients.

Conclusions:

• DTI abnormalities in the transcallosal motor tract (corpus callosum body) distinguish PIGD from PD, not substantia nigra changes.
• The extent of corpus callosum body abnormality identified by DTI correlates with the Tinetti score, indicating its relevance to fall risk.