Introduction: The reduction of hippocampal volume in mesial temporal lobe epilepsy(TLE) patients has been shown by using volumetric analysis in previous studies. We investigated differences of hippocampal subfields volume according to lesion type, coexistence of focal cortical dysplasia(FCD), duration of disease and other clinical variables.
Methods: Thirty-four clinically diagnosed TLE patients who underwent surgery to control intractable epilepsy were enrolled. Preoperative MRI findings, pathologic diagnoses, type and duration of seizure with hippocampal subfields volume were analyzed. Freesurfer hippocampal subfield analysis tool(v 6.0)was used for volumetric analysis
Results: Preoperative diagnoses were hippocampal sclerosis(HS) 22, bilateral TLE 5, lateral temporal lobe FCD 2, tumor 2, cavernous malformation 2. Radiologically normal hippocami were 14 cases and 6 of them were pathologically diagnosed as HS. There were 6 cases of FCD on temporal lobe coexist with HS. Significant volume reduction of hippocampus were found in HS. There were inverse correlation between subfields volume(CA1,CA3, CA4, subiculum, pre and parasubiculum, hippocampal tail) and disease duration. Significantly low volume were only observed in Rt parasubiculum in Rt TLE patients in preoperative GTC seizure group. There was no difference in hippocampal subfield volume whether FCD is coexist or not. Bilateral TLE showed significantly lower volume than control group. Right HS showed lower volume of bilateral hippocampi than control but Left HS showed lower volume of hippocampus only in the ipsilateral side.
Conclusions: We found inverse correlation between disease duration and hippocampal subfields in TLE patients. Bilateral TLE showed smaller hippocampal volume than control. There was no significant hippocampal subfields volume difference whether coexistence of FCD on temporal lobe
Patient Care: This result will help to understand morphological changes in ipsilateral and bilateral temporal lobe epilepsy patients.
Learning Objectives: Volumetric change in surgically treated TLE patients