Background: Refractory epilepsy is a concern for many canines diagnosed with idiopathic epilepsy. In humans, refractory epilepsy is most often associated with temporal lobe epilepsy (TLE). In dogs, TLE pathology can go unnoticed on standard magnetic resonance imaging (MRI) examination. In recent years, many studies have described the occurrence of TLE in dogs and cats diagnosed through volumetric evaluation of the hippocampus. Nevertheless, this has been performed manually, which may reduce the diagnostic sensitivity of the method. Additionally, due to the challenges involved in the manual assessment in dogs, volumetric evaluation of the brain lobes has not yet been possible. In contrast, automated volumetry has long been used for the diagnosis of many neurological diseases in humans. The development of veterinary medicine and availability of brain atlases has now made it possible to introduce automated volumetry in to veterinary neurology as well. Thus, this study aimed to develop an automatic volumetry method, translate the outcomes into the assessment of temporal lobe volume in dogs with idiopathic epilepsy, and correlate the results with the electroencephalography (EEG) of epileptiform discharges (EDs).
Results: An automated volumetry method was developed in this study, which allowed the evaluation of temporal lobe volumes of 31 dogs diagnosed with idiopathic epilepsy. The asymmetric ratio (AR) was then estimated and the results were correlated with the EEG EDs. Notably, 12/31 dogs had an AR greater than 6%. Among them, reduction in temporal lobe volume correlated with the side of the EEG EDs in seven cases. However, statistical analysis revealed no correlation between temporal lobe volume changes and ED location. There was a statistically significant difference in the AR between the group with a larger right ventricle and the group with symmetrical ventricles.
Conclusions: Our results may influence the classification of idiopathic epilepsy in dogs. Additionally, the diagnosis of TLE in dogs based on MRI volumetry in correlation with EEG examination, especially for dogs with drug-resistant epilepsy, can significantly influence the development of new therapeutic options such as surgery.