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Updated: Mar 7, 2026
Anteromesial Temporal Lobectomy for Medically Intractable Temporal Lobe Epilepsy: An Operative Study
Published on: August 15, 2025
18F-FDG-PET patterns of surgical success and failure in mesial temporal lobe epilepsy
Francine Chassoux1, Eric Artiges2, Franck Semah2
1From the Department of Neurosurgery (F.C., A.L., E.L., B.T., B.D.), Sainte-Anne Hospital; Paris-Descartes University (F.C., A.L., E.L., B.T., B.D.); INSERM UMR 1129 (F.C., A.L.), Paris; Nuclear Medicine Department (F.C., P.G., B.-O.H.), SHFJ, CEA/SAC/DRF/IBM Neurospin Gif/Yvette; INSERM (E.A.), Research Unit 1000 "Neuroimaging and Psychiatry," Paris Sud University-Paris Saclay University; Psychiatry Department 91G16 (E.A.), Orsay Hospital, Orsay; Department of Nuclear Medicine and INSERM U 1171 (F.S.), CHU Lille; and INSERM U 1023 (P.G., B.-O.H.), IMIV, CEA, Paris-Sud University, Orsay, France. f.chassoux@ch-sainte-anne.fr.
Objective:
To search for [18F]-fluorodeoxyglucose (FDG)-PET patterns predictive of long-term prognosis in surgery for drug-resistant mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis (HS).
Methods:
We analyzed metabolic data with [18F]-FDG-PET in 97 patients with MTLE (53 female participants; age range 15-56 years) with unilateral HS (50 left) and compared the metabolic patterns, electroclinical features, and structural atrophy on MRI in patients with the best outcome after anteromesial temporal resection (Engel class IA, completely seizure-free) to those with a non-IA outcome, including suboptimal outcome and failure. Imaging processing was performed with statistical parametric mapping (SPM5).
Results:
With a mean follow-up of >6 years (range 2-14 years), 85% of patients achieved a class I outcome, including 45% in class IA. Class IA outcome was associated with a focal anteromesial temporal hypometabolism, whereas non-IA outcome correlated with extratemporal metabolic changes that differed according to the lateralization: ipsilateral mesial frontal and perisylvian hypometabolism in right HS and contralateral fronto-insular hypometabolism and posterior white matter hypermetabolism in left HS. Suboptimal outcome presented a metabolic pattern similar to the best outcome but with a larger involvement of extratemporal areas, including the contralateral side in left HS. Failure was characterized by a mild temporal involvement sparing the hippocampus and relatively high extratemporal hypometabolism on both sides. These findings were concordant with electroclinical features reflecting the organization of the epileptogenic zone but were independent of the structural abnormalities detected on MRI.
Conclusions:
[18F]-FDG-PET patterns help refine the prognostic factors in MTLE and should be implemented in predictive models for epilepsy surgery.
Insights
Positron emission tomography (PET) patterns using [18F]-fluorodeoxyglucose (FDG) can predict long-term outcomes for epilepsy surgery. Specific metabolic patterns in the brain help determine the likelihood of seizure freedom after surgery for mesial temporal lobe epilepsy with hippocampal sclerosis.
Area of Science:
- Neurology
- Nuclear Medicine
- Epileptology
Background:
- Drug-resistant mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS) often requires surgery for seizure control.
- Predicting long-term surgical outcomes in MTLE-HS remains a challenge.
- Identifying reliable prognostic factors is crucial for patient management.
Purpose of the Study:
- To identify [18F]-fluorodeoxyglucose (FDG)-PET metabolic patterns that predict long-term prognosis after surgery for MTLE due to HS.
- To compare metabolic patterns with electroclinical features and MRI findings in patients with varying surgical outcomes.
Main Methods:
- Analysis of [18F]-FDG-PET metabolic data in 97 patients with unilateral HS undergoing anteromesial temporal resection.
- Comparison of metabolic patterns between patients with the best outcome (Engel class IA) and those with non-IA outcomes.
- Utilized statistical parametric mapping (SPM5) for imaging processing.
Main Results:
- A focal anteromesial temporal hypometabolism on FDG-PET predicted the best outcome (Engel class IA).
- Non-IA outcomes correlated with extratemporal metabolic changes, varying by HS lateralization.
- Suboptimal outcomes showed larger extratemporal involvement, while failure indicated mild temporal and high bilateral extratemporal hypometabolism.
- FDG-PET findings were consistent with electroclinical features but independent of MRI structural atrophy.
Conclusions:
- [18F]-FDG-PET patterns are valuable prognostic factors in MTLE surgery.
- Incorporating FDG-PET patterns into predictive models can improve surgical outcome prediction.
- This imaging modality aids in refining prognostic assessments for epilepsy surgery.
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