Patients with epilepsy

The clinical trial to evaluate the efficacy of [¹¹C]K-2 in refractory epilepsy patients undergoing anterior temporal lobectomy (trial registry number UMIN000025090) was carried out to examine the efficacy of [¹¹C]K-2 in measuring the density of AMPA receptors in patients with epilepsy. Detailed information about the participants and the study design was previously reported by Miyazaki et al.¹⁶ In short, eight patients diagnosed with refractory MTLE based on a non-invasive assessment met the eligibility criteria and were registered. Five of the eight patients underwent MEG, and one underwent iEEG, all of whom provided data that were analysed in this study. Five patients (one male and four females) with drug-resistant MTLE underwent respective temporal surgery at the National Center Hospital, National Center of Neurology and Psychiatry, and had undergone at least 1 year of postoperative follow-up. The clinical characteristics of the patients are summarized in Table 1. The mean age at the PET examination of [¹¹C]K-2 was 39.8 years (range, 21–58 years). The mean duration from the diagnosis of epilepsy to the PET examination of [¹¹C]K-2 was 32.4 years (range, 8–51 years).

Clinical characteristics

AED, anti-epileptic drug; aT, anterior temporal; a-mT, anterior-middle temporal; ATL, anterior temporal lobectomy; HS, hippocampal sclerosis; IFG, inferior frontal gyrus; L, left; MTG, middle temporal gyrus; R, right; T, temporal.

All five patients underwent presurgical comprehensive epilepsy evaluations that included medical interviews, neurological and neuropsychological examinations, long-term video-electroencephalography, MRI, ¹⁸F-fluorodeoxyglucose-PET (FDG-PET) and MEG. Epilepsy histories were obtained from the patients and their relatives, and the semiology of their habitual seizures was confirmed. The epilepsy diagnoses and classifications were established after comprehensive evaluations. The MRI evaluations revealed structural abnormalities in all patients, and four of the five had hippocampal sclerosis (Table 1). Abnormal hypometabolism on FDG-PET was also observed in all the patients.