Making the Invisible Visible: Advanced Neuroimaging Techniques in Focal Epilepsy.

Daichi Sone

doi:10.3389/fnins.2021.699176

Abstract

It has been a clinically important, long-standing challenge to accurately localize epileptogenic focus in drug-resistant focal epilepsy because more intensive intervention to the detected focus, including resection neurosurgery, can provide significant seizure reduction. In addition to neurophysiological examinations, neuroimaging plays a crucial role in the detection of focus by providing morphological and neuroanatomical information. On the other hand, epileptogenic lesions in the brain may sometimes show only subtle or even invisible abnormalities on conventional MRI sequences, and thus, efforts have been made for better visualization and improved detection of the focus lesions. Recent advance in neuroimaging has been attracting attention because of the potentials to better visualize the epileptogenic lesions as well as provide novel information about the pathophysiology of epilepsy. While the progress of newer neuroimaging techniques, including the non-Gaussian diffusion model and arterial spin labeling, could non-invasively detect decreased neurite parameters or hypoperfusion within the focus lesions, advances in analytic technology may also provide usefulness for both focus detection and understanding of epilepsy. There has been an increasing number of clinical and experimental applications of machine learning and network analysis in the field of epilepsy. This review article will shed light on recent advances in neuroimaging for focal epilepsy, including both technical progress of images and newer analytical methodologies and discuss about the potential usefulness in clinical practice.

Highlights

Epilepsy is a common chronic brain disease, which affects around 50 million people all over the world (Leonardi and Ustun, 2002; GBD 2016 Epilepsy Collaborators, 2019)
Neuroimaging is an essential examination for epilepsy, and one of its major roles is to visualize epileptogenic lesions, in patients with drug-resistant focal seizures (Bernasconi et al, 2019)
Since unsuccessful localization of focus by MRI may lead to poorer surgical seizure outcome (So and Lee, 2014), accurate visualization of epileptogenic lesions by neuroimaging techniques has been a long-standing challenge in epilepsy

Summary

INTRODUCTION

Epilepsy is a common chronic brain disease, which affects around 50 million people all over the world (Leonardi and Ustun, 2002; GBD 2016 Epilepsy Collaborators, 2019). To detect the conventionally invisible epileptogenic lesions, efforts have been made to seek for useful advanced neuroimaging techniques in drug-resistant focal epilepsy (Bernasconi and Wang, 2021). Fluid and white matter suppression (FLAWS) has been reported for better visualization of focal cortical dysplasia even in conventionally MRI-negative cases (Chen et al, 2018a; Sun et al, 2021). Studies on machine learning and epilepsy imaging reported its usefulness in the lateralization of TLE (Pustina et al, 2015; Bennett et al, 2019; Beheshti et al, 2020a,b) or automated detection of focal cortical dysplasia (Hong et al, 2014; Hong et al, 2016; Adler et al, 2017; Tan et al, 2018). Clinical and basic applications of advanced neuroimaging would be promising for better understanding and improved clinical practice for epilepsy

CONCLUSION

Findings

LIMITATION AND FUTURE CHALLENGE