Abstract
2420
Introduction: Temporal lobe epilepsy (TLE), as the most common drug-refractory epilepsy, could be divided into mesial temporal lobe epilepsy (MTLE) and neocortical temporal lobe epilepsy (NTLE) in terms of location of the epileptic focus. The response of these two types of TLE to surgical treatment is quite different. In addition, there are many noninvasive presurgical evaluations, but it is still difficult for epileptologists to distinguish NTLE from MTLE. Our study is aimed at using fluorine-18-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) to determine the discrepancy of metabolic profiles of MTLE and NTLE, as well as the correlation with surgical prognosis.
Methods: From January 2016 to June 2021, we recruited 137 patients with intractable TLE and 40 age-matched healthy controls at Xiangya Hospital of Central South University. We have collected the history, seizure symptoms, magnetic resonance imaging, video electroencephalography (EEG) and invasive stereo-EEG (SEEG) recording, surgery data, and prognosis of patients enrolled. 18F-FDG-PET was used to measure the metabolism of regional cerebral of all participants. Localization of the epileptic zone and therapy was determined by a multidisciplinary team. According to the comprehensive data, patients were divided into two subgroups: MTLE group (N = 91) and NTLE group (N = 46). We compared the clinical data, standardized uptake value ratio (SUVr) in MTLE and NTLE groups. The standardized uptake values were computed for the mesial and lateral temporal lobe, along with SUVr between the temporal lobe and cerebellum. Metabolic patterns of regional cerebral were analyzed for MTLE, NTLE, and healthy control groups using statistical parametric mapping 12 (SPM12).
Results: There was no significant difference in age, sex distribution, onset age, duration of epilepsy and seizure frequency between the MTLE and NTLE groups. Of all TLE patients, 76 MTLE patients and 23 NTLE patients underwent resection of epileptic lesions. With an average follow-up of 2.9 years after surgery, 51 (67.1%) patients in the MTLE group and 10 (43.5%) in NTLE achieved Engel class IA (p=0.041). The difference in SUVr of the ipsilateral lateral temporal lobe was statistically significant between two groups (MTLE vs. NTLE, 0.843±0.177 vs. 0.937±0.217, p=0.038), while there is no significant difference in SUVr of the ipsilateral mesial temporal lobe (MTLE vs. NTLE, 0.749±0.136 vs. 0.791±0.122, p=0.187). The cerebral hypometabolism of MTLE is limited to the ipsilateral temporal and insular lobe compared with healthy controls (p<0.001). However, in addition to ipsilateral temporal lobe, the NTLE patients showed hypometabolism in the ipsilateral frontal lobes and parietal lobe (p<0.001). When it comes to regional cerebral hypermetabolism, the MTLE patients showed extensive changes in contralateral temporal, bilateral frontoparietal regions, cingulate gyrus, corpus callosum, thalamus, basal ganglia, brainstem and cerebellum (p<0.001). The hypermetabolism in brain with NTLE is limited, including partial areas in contralateral temporal lobe, ipsilateral cerebellum, frontal, occipital lobe and bilateral thalamus (p<0.001).
Conclusions: The 18F-FDG uptake of ipsilateral temporal area in patients with TLE is lower than of healthy controls. Hypometabolism in ipsilateral lateral temporal lobe could be used to distinguish NTLE from MTLE. MTLE mainly showed hypermetabolism in areas other than epileptic foci, while NTLE is mainly characterized by broader hypometabolism including epileptic foci, which suggested the pathogenesis, propagation mode and path of MTLE and NTLE could be different, resulting in different responses to surgery. Abnormal interictal metabolic disturbance and the differences of SUVr of ipsilateral lateral temporal lobe in MTLE and NTLE may be indicators to make a distinction of two types of TLE, which is important in the delineation of epileptic foci extent and surgical planning.
In this issue
Jump to section
Related Articles
Cited By...
- No citing articles found.