Multimodal combination of neuroimaging methods for localizing the epileptogenic zone in MR-negative epilepsy

Abstract

The objective was to determine the optimal combination of multimodal imaging methods (IMs) for localizing the epileptogenic zone (EZ) in patients with MR-negative drug-resistant epilepsy. Data from 25 patients with MR-negative focal epilepsy (age 30 ± 10 years, 16M/9F) who underwent surgical resection of the EZ and from 110 healthy controls (age 31 ± 9 years; 56M/54F) were used to evaluate IMs based on 3T MRI, FDG-PET, HD-EEG, and SPECT. Patients with successful outcomes and/or positive histological findings were evaluated. From 38 IMs calculated per patient, 13 methods were selected by evaluating the mutual similarity of the methods and the accuracy of the EZ localization. The best results in postsurgical patients for EZ localization were found for ictal/ interictal SPECT (SISCOM), FDG-PET, arterial spin labeling (ASL), functional regional homogeneity (ReHo), gray matter volume (GMV), cortical thickness, HD electrical source imaging (ESI-HD), amplitude of low-frequency fluctuation (ALFF), diffusion tensor imaging, and kurtosis imaging. Combining IMs provides the method with the most accurate EZ identification in MR-negative epilepsy. The PET, SISCOM, and selected MRI-post-processing techniques are useful for EZ localization for surgical tailoring.

Neurological update: structural and functional imaging in epilepsy surgery

“…Researchers have endeavoured to define an optimal battery of imaging modalities for presurgical localisation of the epileptogenic zone in MR-negative focal epilepsies [ 67 ]. Quadrimodal imaging procedures involving a hybrid PET/MR scanner (for single-session FDG-PET and MRI) and simultaneous high-density EEG-fMRI (256 electrodes), in a single session has been used to minimise scanning and recording sessions.…”

The diagnostic value of ictal SPECT—A retrospective, semiquantitative monocenter study

“…The standard presurgical evaluation includes electroencephalography (EEG) examinations, analysis of semiology, neuropsychological testing, and magnetic resonance imaging (MRI) 1 . Ictal single photon emission computed tomography (SPECT) can be used as an advanced diagnostic modality to detect the SOZ 2–4 . However, including video and EEG monitoring of epileptic seizures and possible multiple injections of the tracer, ictal SPECT is an expensive and time‐consuming imaging modality 5,6 in which individuals are exposed to an average radiation dose of 6.8 millisievert (mSv) 7 .…”

“… 1 Ictal single photon emission computed tomography (SPECT) can be used as an advanced diagnostic modality to detect the SOZ. 2 , 3 , 4 However, including video and EEG monitoring of epileptic seizures and possible multiple injections of the tracer, ictal SPECT is an expensive and time‐consuming imaging modality 5 , 6 in which individuals are exposed to an average radiation dose of 6.8 millisievert (mSv). 7 The added value of SPECT is seen particularly in people with extratemporal epilepsies and those in whom no potentially epileptogenic lesion could be detected in MRI (MR‐negative).…”

Contribuição diagnóstica da subtração entre os SPECTs crítico e intercrítico e seu alinhamento com a ressonância magnética (SISCOM), na avaliação pré-cirúrgica de pacientes com epilepsia associada à displasia cortical focal

“…As imagens de SPECT contribuíram em nosso estudo como método confirmatório para a localização da área de maior intensidade do SISCOM, facilitando a associação com a clínica do paciente, e principalmente como referência nos casos em que a RM era considerada negativa. Assim como realizado por Kudr et al (2016) de resultados verdadeiros positivos do processamento em pacientes que realizaram cirurgia de epilepsia (Chen and Guo ,2016;ŘÍHA et al, 2022).…”