FLAIR-Wise Machine-Learning Classification and Lateralization of MRI-Negative 18F-FDG PET-Positive Temporal Lobe Epilepsy.

Iman Beheshti,Hiroshi Matsuda,Noriko Sato,Norihide Maikusa,Daichi Sone,Yukio Kimura,Yoko Shigemoto

doi:10.3389/fneur.2020.580713

Abstract

Objective: In this study, we investigated the ability of fluid-attenuated inversion recovery (FLAIR) data coupled with machine-leaning algorithms to differentiate normal and epileptic brains and identify the laterality of focus side in temporal lobe epilepsy (TLE) patients with visually negative MRI.Materials and Methods: The MRI data were acquired on a 3-T MR system (Philips Medical Systems). After pre-proceeding stage, the FLAIR signal intensities were extracted from specific regions of interest, such as the amygdala, cerebral white matter, inferior temporal gyrus, middle temporal gyrus, parahippocampal gyrus, superior temporal gyrus, and temporal pole, and fed into a classification framework followed by a support vector machine as classifier. The proposed lateralization framework was assessed in a group of MRI-negative unilateral TLE patients (N = 42; 23 left TLE and 19 right TLE) and 34 healthy controls (HCs) based on a leave-one-out cross-validation strategy.Results: Using the FLAIR data, we obtained a 75% accuracy for discriminating the three groups, as well as 87.71, 83.01, and 76.19% accuracies for HC/right TLE, HC/left TLE, and left TLE/right TLE tasks, respectively.Interpretation: The experimental results show that FLAIR data can potentially be considered an informative biomarker for improving the pre-surgical diagnostic confidence in patients with MRI-negative TLE.

Highlights

Temporal lobe epilepsy (TLE), the most common focal epilepsy in adults, has good surgical outcomes despite its association with drug resistance [1]
In this study, we investigated the ability of fluid-attenuated inversion recovery (FLAIR) data coupled with machine-leaning algorithms to differentiate normal and epileptic brains and identify the laterality of focus side in temporal lobe epilepsy (TLE) patients with visually negative magnetic resonance imaging (MRI)
All TLE patients showed unilateral glucose hypometabolism including the temporal lobe in interictal FDG positron emission tomography (PET) consistent with the clinical symptoms and EEG abnormalities, without any evidence of morphological abnormality on visual assessment of MRI scans

Summary

Introduction

Temporal lobe epilepsy (TLE), the most common focal epilepsy in adults, has good surgical outcomes despite its association with drug resistance [1]. About 30% of people with TLE show no abnormalities or epileptogenic lesions on conventional MRI [3] This type of TLE patient has visually normal brain MRI and is said to have “MRI-negative TLE.”. When 18F-FDG PET provides positive findings in MRI-negative TLE, surgical treatment is associated with favorable prognosis in patients with hippocampal sclerosis [6,7,8]. Because FLAIR signal abnormality is sometimes found in epileptogenic lesions and astrogliosis [2, 11], the optimal pattern classification of FLAIR signals may provide significant clinical lateralization in patients with visually MRI-negative TLE

Methods

Results

Conclusion