Mapping Microstructural Myelin and Axonal Damage in Dogs with Idiopathic Epilepsy using Diffusion MRI and Tract-Based Spatial Statistics
Principal Investigator: Philippa Johnson
DESCRIPTION (provided by applicant):
Idiopathic epilepsy is a common condition in the dog. A subset of epileptics show resistance to antiepileptic drug (AED) therapy and continue to seizure, resulting in high mortality rates. The epileptic brain is known to have both primary lesions, forming the epileptogenic focus, as well as sites of axonal and myelin injury secondary to seizures. Despite the extent of neuropathology present in the brain, the majority of dogs with epilepsy show no abnormalities on clinical MRI scans, limiting diagnosis. The advanced MRI technique of diffusion tensor imaging (DTI) is sensitive to microstructural abnormalities within white matter. These alterations in water diffusion can be mapped at the voxel level using the processing technique of tract based spatial statistics (TBSS). We aim to apply these techniques to the evaluation of the epileptic dog brain. DTI data acquired from a cohort of 10 dogs with AED resistant idiopathic epilepsy will be compared to a healthy control cohort. Statistically significant differences in diffusivity parameters will be mapped across the brain using TBSS. We hypothesize that diffusivity in specific regions of the white matter will be altered in dogs with epilepsy. The changes identified will correspond to axonal and myelin injury associated with the primary epileptogenic foci and/or secondary seizure related brain injury. This will be the first study to map epilepsy associated brain lesions in the dog in vivo. In doing so we advanced our understanding of the neuropathology present in this condition and lay the foundation for improving diagnosis and classification of epilepsy.