BACKGROUND AND PURPOSE
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.
METHODS
Patients with possible nonlesional drug‐refractory insular epilepsy underwent a voxel‐based 1H‐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.
RESULTS
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.
CONCLUSIONS
Our preliminary findings suggest that 1H‐MRS fares poorly in identifying patients with nonlesional insular epilepsy.