Proton MR Spectroscopy in Patients with Nonlesional Insular Cortex Epilepsy Confirmed by Invasive EEG Recordings.
Recent studies suggest that a nonnegligible proportion of drug-resistant epilepsy surgery candidates have an epileptogenic zone that involves the insula. We aimed to examine the value of proton magnetic resonance spectroscopy (1H-MRS) in identifying patients with insular cortex epilepsy.



Patients with possible nonlesional drug-refractory insular epilepsy underwent a voxel-based1H-MRS study prior to an intracranial electroencephalographic (EEG) study. Patients were then divided into two groups based on invasive EEG findings: the insular group with evidence of insular seizures and the noninsular group with no evidence of insular seizures. Sixteen age-matched healthy controls were also scanned for normative data.



Twenty-two epileptic patients were recruited, 12 with insular seizures and 10 with extra-insular seizures. Ipsilateral and contralateral insular N-acetyl-aspartate concentrations ([NAA]) and NAA/Cr ratios were found to be similar in both patient groups. No significant differences in [NAA] or NAA/Cr ratios were found between the insular group, noninsular group, and healthy controls. [NAA] and NAA/Cr asymmetry indices correctly lateralized the seizure focus in only 16.7% and 0% of patients, respectively.



Our preliminary findings suggest that1H-MRS fares poorly in identifying patients with nonlesional insular epilepsy.
Department of Neurosciences, Université de Montréal, Canada.
Yasmine
Y
Aitouche
Department of Neurosciences, Université de Montréal, Canada.|Division of Neurology, Hôpital du Sacré-Cœur de Montréal, Université de Montréal, Canada.
Steve A
SA
Gibbs
MR Clinical Science, Philips Healthcare, Canada.|Department of Radiology, CHUM Notre-Dame, Université de Montréal, Canada.
Guillaume
G
Gilbert
Department of Psychology, Université de Montréal, Canada.
Olivier
O
Boucher
Division of Neurosurgery, CHUM Notre-Dame, Université de Montréal, Canada.
Alain
A
Bouthillier
Department of Neurosciences, Université de Montréal, Canada.|Division of Neurology, CHUM Notre-Dame, Université de Montréal, Canada.
Dang Khoa
DK
Nguyen
D000328:Adult; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000378:metabolism; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D055815:Young Adult
Epilepsy; insula; proton magnetic resonance spectroscopy