¹⁸FDG‐PET in different subtypes of temporal lobe epilepsy: SEEG validation and predictive value

Abstract

SUMMARYObjective: The objective of the study was to characterize interictal 18-fluorodeoxyglucose-positron emission tomography ( 18 FDG-PET) whole-brain voxel-based metabolic patterns among distinct subtypes of temporal lobe epilepsy (TLE), as defined by stereo-electroencephalography (SEEG) and to determine predictive value of PET result on postoperative outcome. Methods: Fifty-four consecutive patients with pharmacoresistant TLE were enrolled retrospectively after a comprehensive presurgical evaluation. This evaluation defined: 7 lateral TLE, 17 mesial TLE, 14 "plus" TLE, and 16 bilateral TLE. Whole-brain voxelbased brain metabolism was studied in each group of patients, in comparison to 23 healthy subjects, and individual classification was evaluated by cross-validation using the found clusters. An 18 FDG-PET index was moreover calculated for each patient, based on the individual Z-score of the most significant cluster extracted on the comparison between patients' subgroup and healthy subjects. Logistic regression analysis was used to estimate factors associated with postoperative outcome (Engel's classes III-IV vs. I-II), including age, gender, disease duration, seizure frequency, as well as magnetic resonance imaging (MRI) and PET findings. Results: Different patterns of hypometabolism were found inside and outside the epileptogenic zone, among patients with distinct subgroups of TLE, in comparison to healthy subjects (p < 0.001, corrected for the cluster). At individual level, cross-validation showed satisfactory discrimination between the four groups with 71.4-88.2% overall accuracy. Multivariate analysis shows that 18 FDG-PET index was the only significant predictor of postoperative outcome to distinguish between Engel's classes I-II and III-IV (p = 0.037). Significance: Overall, this whole-brain voxel-based analysis validates specific patterns of hypometabolism, inside and outside the EZ, in distinct subgroups of patients with TLE, as defined by SEEG gold standard, and in relation with postoperative outcome.

Metabolic patterns and seizure outcomes following anterior temporal lobectomy

“…18 F-Fluorodeoxyglucose positron emission tomography ( 18 FDG-PET) is one of the most established functional imaging modalities employed in the evaluation of epilepsy surgery candidates and offers unique insights into cerebral glucose metabolism at the synaptic level. 1,2 Accordingly, the need for reliable predictors of treatment outcomes in this era of personalized medicine remains ongoing.…”

“…1,2 Accordingly, the need for reliable predictors of treatment outcomes in this era of personalized medicine remains ongoing. [7][8][9][10][11] With the advances in electroencephalography (EEG) and imaging technologies, including multimodal coregistration techniques, the role of 18 FDG-PET in presurgical evaluation has been enhanced beyond being a useful diagnostic tool reserved for magnetic resonance imaging (MRI)-negative cases or clinical scenarios with discordant electroclinical and structural imaging findings. [3][4][5][6] The costefficiency of 18 FDG-PET has long been recognized, and the wider availability of postacquisition processing techniques has increased its yield in surgical planning.…”

“…[3][4][5][6] The costefficiency of 18 FDG-PET has long been recognized, and the wider availability of postacquisition processing techniques has increased its yield in surgical planning. 17,18 Furthermore, the findings of recent 18 FDG-PET and functional connectivity studies have been convergent in demonstrating the role of 18 FDG-PET as a metabolic biomarker of the extent of the epileptic network dysfunction. [12][13][14][15][16] There has been a growing body of evidence suggesting that the extent of the metabolic compromise correlates with the distribution of ictal EEG discharges.…”

Presurgical Mapping of Brain Tumors Using Statistical Probabilistic Anatomical Maps

“…In the sample case, the probabilistic anatomical region of the glioma included 8.9% of the precentral gyrus, 36.8% of the postcentral gyrus, 21.7% of the superior parietal gyrus, 10.9% of the supramarginal gyrus, 6.6% of the angular gyrus, and 14.8% of Brodmann's area 44. 18 F FLT PET imaging data. The probability of a SPAM-labeled brain glioma region could be extracted using a combination of the inverse normalized SPAM and the segmented glioma region.…”

“…Brain tumors are the most common solid tumors, and are typically evaluated by 18 F FDG PET (FDG) or by combined FDG and MR imaging [1]. The hybrid PET/MR allows for molecular, anatomical, and functional imaging such as ASL, proton-spectroscopy, 11 C methionine PET, and 68 Ga DOTATOC PET [2].…”