Diffusion tensor imaging analysis of aged dogs with and without canine cognitive dysfunction.

Area of Science:

• Neuroimaging
• Veterinary Neurology
• Comparative Medicine

Background:

• Canine cognitive dysfunction (CCD) mirrors Alzheimer's disease (AD) in dogs, yet in vivo imaging, particularly DTI, remains underutilized for assessing brain atrophy.
• Limited research exists on using DTI to evaluate white matter microstructure changes in CCD.

Purpose of the Study:

• To investigate DTI's ability to detect differences in white matter microstructure between aged dogs with CCD and healthy controls.
• To explore correlations between DTI parameters and cognitive scores using the Canine Dementia Scale (CADES).

Main Methods:

• Diffusion tensor imaging (DTI) was employed to analyze white matter integrity.
• Comparison of DTI parameters (FA, MD, AxD, RD) in the corpus callosum and thalamus between CCD and healthy aged dogs.
• Correlation analysis between DTI metrics and CADES scores.

Main Results:

• Dogs with CCD exhibited significantly higher mean diffusivity (MD) in the thalamus compared to healthy controls (p=0.022).
• CADES scores positively correlated with MD in the corpus callosum (p=0.0471) and thalamus (p=0.0038).
• CADES scores also correlated with radial diffusivity (RD) in the thalamus (p=0.0144).

Conclusions:

• DTI effectively identifies white matter integrity changes in the canine brain associated with CCD.
• Increased MD and RD values in CCD dogs suggest axonal degeneration correlating with cognitive impairment.
• Findings support DTI's potential for monitoring CCD progression and highlight CCD's translational relevance as an AD model.