Abstract
Background
Canine cognitive dysfunction (CCD) is a naturally occurring disease in aged dogs that shares many behavioural and pathological similarities with Alzheimer’s disease. There has been little research on in vivo imaging of CCD, and to the best of our knowledge, no studies have investigated the use of diffusion tensor imaging (DTI) to visualize brain atrophy. The primary aim of this study was to determine the applicability of DTI for imaging various regions of the canine brain. A secondary aim was to determine whether DTI could be used to differentiate healthy aging dogs from dogs with CCD. We hypothesized that DTI could be used to image the canine brain, providing insight into the diffusivity of axons in various regions, and could reveal differences in DTI parameters between dogs with and without CCD. DTI was used to measure the mean fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD) and radial diffusivity (RD) in the corpus callosum (CC) and thalamus of the dogs.
Results
Our data revealed that DTI can be used to image the diffusivity of the CC and thalamus and revealed an overall decrease in the mean FA and increase in the mean MD, AxD, and RD in these two structures in dogs with CCD compared to healthy dogs. Further research is required to determine whether DTI has the ability differentiate aged dogs from dogs with CCD.
Conclusions
These results demonstrated that DTI could be used to evaluate white matter integrity in the canine brain with and without CCD, indicating that the use of DTI could provide valuable insight into neuropathological changes due to CCD, revealing further translational applicability of CCD as a model for AD.