Mangenese-enhanced MRI reflects seizure outcome in a model mesial temporal lobe epilepsy.

By: Dedeurwaerdere..O'Brien Introduction: Over the past few decades, mangenese-enhanced magnetic resonance imaging (MeMRI) has been developed as a tool in studying brain structure and neuronal activity in vivio. As a paramagnetic ion, it works as a functioning contrast agent for MR imaging, with the benefits of being essentially non-toxic at low doses. Utilizing this technique, this paper was able to look at neurological changes in an epileptic model compared to a normal standard, in order to better understand the changes occurring in various sub-fields of the hippocampus. In the kainic acid-induced epileptic model (KASE) increases in mossy fibre were seen compared to the normal non-epileptic model. Methods: -Implantation of guide cannula in order to induce Kainic Acid-Induced Epilepsy (KASE) -MeMRI acquisition and analysis -Video EEG Monitoring -Histology Results: The chronic stage KASE model experienced decreased hippocampal volume and enlarged ventricle. Where as, early and chronic KASE models were seen to have significantly decreased CA1 sub-regions of the hippocampus. Interestingly, after MeMRI analysis it was found that both the DG and CA1 regions had increased mangenese voxel intensities in the KASE model. It turned out that an inverse correlation was found between MeMRI signal intensity in the DG of the chronic model and future epileptic seizing. It was also observed using histology, that chronic KASE models had increased mossy fibre sprouting. However, this increase did not correlate with spontaneous seizing or MeMRI voxel intensity. It is thought that increased mossy fibre growth may have been counterbalanced in MeMRI by overall cell loss. It is still uncertain as to why an inverse correlation was found between MeMRI intensity and future seizing in the chronic KASE model, and needs further investigation. ~JI