Introduction: Amygdalohippocampal area is a critical target in the patients with Mesial Temporal Sclerosis (MTS) who undergo Selective Laser Amygdalohippocampectomy (SLAH) surgical treatment. The Amygdalohippocampal functional interactions and their association with post-surgical outcomes have not yet been determined. In this study, we aim to establish Amygdalohippocampal circuits in patients with left MTS as a predictive tool with respect to post-surgical outcomes using resting stat functional MRI (rsfMRI).
Methods: A total of 18 patients with left TLE (8 males, 10 females, 22-55 age range) underwent to SLAH and were imaged using 3.0T Philips Achieva MR scanner. Of the participants, 7 patients still were experienced seizures after 6 months follow up and 11 were seizure free. In this study, a seed-based functional connectivity (FC) analysis was performed. Regions of interest (ROIs) were defined using a combination of 106 ROIs in the Harvard-Oxford atlas as well as 26 areas in the cerebellum from the AAL atlas. Changes in FC were examined between the ipsilateral amygdalohippocampal and contralateral amygdalohippocampal and any of ROIs respectively. To assess the relationship between response to SLAH and FC, the 18 left MTS patients were divided into two groups: responders (n=11) and non-responders (n=7).
Results: ROI-to-voxel analysis showed that response to SLAH was associated with synchronization between ipsilateral amygdalohippocampal and precuneus (825 voxels, 15%), ipsilateral frontal orbital cortex (714 voxels, 43%), ipsilateral putamen (401 voxels, 46%), contralateral superior parietal lobule (369 voxels, 25%) and cingulate gyrus (245 voxels, 15%). Response to SLAH was also associated with synchronization between contralateral amygdalohippocampal and precuneus (652, 12%), contralateral superior parietal lobule (358, 25%), ipsilateral putamen (488, 60%) and ipsilateral orbital cortex (2977, 21%)
Conclusions: In this work, we sought to identify an objective imaging biomarker to predict early response to SLAH in patients with left MTS. We used rsfMRI to examine synchronization between the amygdalohippocampal and associated cortical circuits Together, these findings indicate characteristic resting state imaging patterns that have the potential to be used in the pre-surgical setting to predict which patients are more likely to preferentially respond early to SLAH.
Patient Care: This study has potential to stratify surgical treatments in patients with epilepsy.
Learning Objectives: These preliminary findings imply the clinical importance of functional MRI in left MTS patients as well as predicting who respond most favorably to SLAH.