Open Access
Evaluation of magnetic resonance imaging-negative drug-resistant epilepsy
Author(s) -
Aashit Shah,
Sandeep Mittal
Publication year - 2014
Publication title -
annals of indian academy of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 31
eISSN - 1998-3549
pISSN - 0972-2327
DOI - 10.4103/0972-2327.128667
Subject(s) - hippocampal sclerosis , medicine , neuroimaging , epilepsy , magnetic resonance imaging , epilepsy surgery , lesion , radiology , neuroscience , pathology , temporal lobe , psychology , psychiatry
A structural brain lesion in patients with drug-resistant epilepsy (DRE) greatly increases the likelihood of identification of the seizure focus and ultimately seizure-free outcome following resective epilepsy surgery. In contrast, surgical outcomes of true non-lesional DRE are less favorable. Therefore, discovery of an underlying lesion is paramount in the pre-surgical work-up of patients with DRE. Over the years, the surgical treatment of pharmacoresistant epilepsy has evolved from straightforward lesional cases to include cases with hippocampal sclerosis. With the advent of magnetic resonance imaging (MRI), most cases of mesial temporal sclerosis became more easily identifiable on pre-operative neuroimaging. With the widespread use of high-resolution MRI with epilepsy protocols over the last two decades, our ability to visualize subtle structural changes has been greatly enhanced. However, there are some cases of lesional epilepsy, which remain unidentified on these routine MRIs. In such "non-lesional" refractory epilepsies, further investigation with advanced neuroimaging techniques, including metabolic imaging, as well as electrophysiological studies may help to identify the previously non-visualized focal brain abnormalities. In this review, we outline the current status for evaluation of MRI-negative DRE.