Pilot Study of Voxel-Based Morphometric MRI Post-processing in Patients With Non-lesional Operculoinsular Epilepsy.

Wei Wang,Liping Li,Wei Du,Cuiping Xu,Yueshan Piao,Siqi Wu,Zhilian Zhao,Yuping Wang,Xiating Zhang,Qilin Zhou,Yicong Lin,Yajie Wang

doi:10.3389/fneur.2020.00177

Abstract

Objective: The aim of this study was to use voxel-based MRI post-processing in detection of subtle FCD in drug-resistant operculoinsular epilepsy patients with negative presurgical MRI, and by combining magnetoencephalography (MEG) to improve the localization of epileptogenic zone.Methods: Operculoinsular epilepsy patients with a negative presurgical MRI were included in this study. MRI post-processing was performed using a Morphometric Analysis Program (MAP) on T1-weighted volumetric MRI. Clinical information including semiology, MEG, scalp electroencephalogram (EEG), intracranial EEG and surgical strategy was retrospectively reviewed. The pertinence of MAP-positive areas was confirmed by surgical outcome and pathology.Results: A total of 20 patients were diagnosed with operculoinsular epilepsy had non-lesional MRI during 2010–2018, of which 11 patients with resective surgeries were included. MEG showed clusters of single equivalent current dipole (SECD) in inferior frontal regions in five patients and temporal-insular/ frontal-temporal-insular/parietal-insular regions in five patients. Four out of 11 patients had positive MAP results. The MAP positive rate was 36.4%. The positive regions were in insular in one patient and operculoinsular regions in three patients. Three of the four patients who were MAP-positive got seizure-free after successfully resect the MAP-positive and MEG-positive regions (the pathology results were FCD IIb in two patients and FCD IIa in one patient).Conclusions: MAP is a useful tool in detection the epileptogenic lesions in patients with MRI-negative operculoinsular epilepsy. Notably, in order to make a right surgical regime decision, MAP results should always be interpreted in the context of the patient's anatomo-electroclinical presentation.

Highlights

In patients with drug-resistant epilepsy, complete surgical resection of the epileptogenic zone can be an effective treatment
It is reported that operculoinsular epilepsy can have semiology similar to temporal lobe seizures, frontal lobe seizures or parietal lobe seizures [8,9,10,11,12,13]
We reviewed the clinical data of patients who were diagnosed as operculoinsular epilepsy from our surgical database from December 2010 to August 2018 at Xuanwu Hospital, Capital Medical University, which is a large tertiary epilepsy center in China

Summary

Introduction

In patients with drug-resistant epilepsy, complete surgical resection of the epileptogenic zone can be an effective treatment. Detection and delineation of the epileptogenic lesion are essential to the success of epilepsy surgery. Absence of a structural lesion on MRI represents a major challenge for surgical management. Operculoinsular epilepsy is relatively rare, it accounts for a non-negligible proportion of drug-resistant epilepsy surgical candidates and sometimes it can be difficult to be recognized [4,5,6]. Because of the complex physiology and the rich connections to surrounding and remote structures, the clinical manifestations of operculoinsular seizures can be diverse [7]. The apparent heterogeneous and sometimes non-specific clinical manifestations increase the difficulties of the diagnosis of operculoinsular seizures, especially in non-lesional patients. Lack of recognition of operculoinsular seizures may be responsible for some epilepsy surgery failures [6]

Results

Discussion

Conclusion