Seizure outcomes in relation to the extent of resection of the perifocal fluorodeoxyglucose and flumazenil PET abnormalities in anteromedial temporal lobectomy.

Milo Stanišić,Christopher Coello,Pål Gunnar Larsson,Are Hugo Pripp,Marjan Makki Mikkelsen,Torsten Danfors,Arild Egge,Einar Heminghyt,Bård Kronen Krossnes,Jugoslav Ivanović,John Hald

doi:10.1007/s00701-015-2578-2

Milo Stanišić, Christopher Coello + Show 9 more

Open Access

https://doi.org/10.1007/s00701-015-2578-2

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Abstract

BackgroundThe area of predominant perifocal [18F]fluorodeoxyglucose (18F-FDG) hypometabolism and reduced [11C]flumazenil (11C-FMZ) -binding on PET scans is currently considered to contain the epileptogenic zone and corresponds anatomically to the area localizing epileptogenicity in patients with temporal lobe epilepsy (TLE). The question is whether the volume of the perifocal pre-operative PET abnormalities, the extent of their resection, and the volume of the non-resected abnormalities affects the post-operative seizure outcome.MethodsThe sample group consisted of 32 patients with mesial temporal sclerosis who underwent anteromedial temporal lobe resection for refractory TLE. All patients had pathologic perifocal findings on both of the PET modalities as well as on the whole-brain MRI. The volumetric data of the PET and MRI abnormalities within the resected temporal lobe were estimated by automated quantitative voxel-based analysis. The obtained volumetric data were investigated in relation to the outcome subgroups of patients (Engel classification) determined at the 2-year post-operative follow-up.ResultsThe mean volume of the pre-operative perifocal 18F-FDG- and 11C-FMZ PET abnormalities in the volumes of interest (VOI) of the epileptogenic temporal lobe, the mean resected volume of these PET abnormalities, the mean volume of the non-resected PET abnormalities, and the mean MRI-derived resected volume were not significantly related to the outcome subgroups and had a low prediction for individual freedom from seizures.ConclusionsThe extent of pre-surgical perifocal PET abnormalities, the extent of their resection, and the extent of non-resected abnormalities were not useful predictors of individual freedom from seizures in patients with TLE.

Highlights

Temporal lobe epilepsy (TLE) is the most common partial seizure syndrome in adults
Because it has been shown that the interictal 18F-FDG PET usually shows a large area of reduced radiotracer uptake extending beyond the epileptogenic zone [1, 24] and the interictal 11C-FMZ PET may show a more restricted area of decreased tracer binding [31, 40] in patients with refractory temporal lobe epilepsy (TLE), these neuroimaging modalities can be used for lateralization and general localization of the seizure focus, making an a priori hypothesis about subsequent intracranial electrode placement possible [28]
The post-surgical seizure outcome subgroups were not influenced by the volume of the magnetic resonance imaging (MRI)-derived resected brain tissue and the percentage this resected volume represented in the VOIA+H+PH and VOITL (Tables 4 and 5)

Summary

Introduction

Temporal lobe epilepsy (TLE) is the most common partial seizure syndrome in adults. TLE is, often refractory to optimal pharmacological treatment [44]. The common view is that an accurate pre-surgical lateralization and localization of epileptogenic zone in patients with drug-resistant TLE is essential for postoperative seizure freedom. Because it has been shown that the interictal 18F-FDG PET usually shows a large area of reduced radiotracer uptake (hypometabolism) extending beyond the epileptogenic zone [1, 24] and the interictal 11C-FMZ PET may show a more restricted area of decreased tracer binding [31, 40] in patients with refractory TLE, these neuroimaging modalities can be used for lateralization and general localization of the seizure focus, making an a priori hypothesis about subsequent intracranial electrode placement possible [28]. The area of predominant perifocal [18F]fluorodeoxyglucose (18F-FDG) hypometabolism and reduced [11C]flumazenil (11C-FMZ) -binding on PET scans is currently considered to contain the epileptogenic zone and corresponds anatomically to the area localizing epileptogenicity in patients with temporal lobe epilepsy (TLE). The question is whether the volume of the perifocal pre-operative PET abnormalities, the extent of their resection, and the volume of the non-resected abnormalities affects the post-operative seizure outcome

Methods

Results

Conclusion