Investigation of idiopathic generalized epilepsies in dogs using magneti̇c resonance spectroscopy

Idiopathic Generalized Epilepsy does not reveal any structural anomalies when examined with Magnetic Resonance Imaging . The advancement of new Magnetic Resonance techniques has enabled the identification of various functional and structural changes in these patients. Magnetic Resonance Spectroscopy provides non-invasive in vivo information regarding the chemical composition of the brain. N-acetylaspartate, creatine , and choline are the main metabolites measured in epileptic patients using MRS. In this study, we aimed to investigate the hypothesis that MRS could detect biochemical changes in the thalamus due to IGE in dogs. Our study was conducted on a group of 20 dogs diagnosed with 'Idiopathic Generalized Epilepsy' according to the 2015 criteria of the International Veterinary Epilepsy Task Force, aged between 6 months and 6 years, who presented to the Surgical Clinic of the Istanbul University-Cerrahpaşa Veterinary Faculty Animal Hospital, and a control group of 10 non-epileptic dogs. All IGE patients underwent electroencephalography. Cranial MRI examinations of both the study and control groups were performed with a 1.5 T (Magnetom Avanto; Siemens Healthineers, 2013, Germany) device using a 12-channel head coil to exclude structural lesions, applying T2-weighted images in sagittal, dorsal, and transversal sequences, FLAIR in dorsal sequence, and T1-weighted in dorsal sequence. Bilateral thalamic NAA/Cr, Cho/Cr, NAA/Cr, and Ins/Cr ratios were measured in patients with IGE and the control group. No significant changes were found in the right and left thalamic NAA/Cr, Cho/Cr, NAA/Cr ratios of the IGE patients compared to the control group. There was no significant difference between the hemispheres of dogs with a single hemisphere-localized epileptogenic focus in the EEG and those without an epileptogenic focus. A significant decrease in Ins/Cr values was observed in the study group. Our findings from MRS did not indicate any signs of neuronal dysfunction or damage. The lack of significant changes in NAA/Cr, Cho/Cr ratios is associated with the patients experiencing few seizures and the MRS measurements being conducted shortly after the onset of clinical symptoms. This highlights the need for larger study groups.