Evaluation of brain FDG PET images in temporal lobe epilepsy for lateralization of epileptogenic focus using data mining methods

Abstract

Background/aim: In temporal lobe epilepsy (TLE), brain positron emission tomography (PET) performed with F-18 fluorodeoxyglucose(FDG) is commonly used for lateralization of the epileptogenic temporal lobe. In this study, we aimed to evaluate the success ofquantitative analysis of brain FDG PET images using data mining methods in the lateralization of the epileptogenic temporal lobe.Materials and methods: Presurgical interictal brain FDG PET images of 49 adult mesial TLE patients with a minimum of 2 years ofpostsurgical follow-up and Engel I outcomes were retrospectively analyzed. Asymmetry indices were calculated from PET images fromthe mesial temporal lobe and its contiguous structures. The J48 and the logistic model tree (LMT) data mining algorithms were used tofind classification rules for the lateralization of the epileptogenic temporal lobe. The classification results obtained by these rules werecompared with the physicians’ visual readings and the findings of single-patient statistical parametric mapping (SPM) analyses in a testset of 18 patients. An additional 5-fold cross-validation was applied to the data to overcome the limitation of a relatively small samplesize.Results: In the lateralization of 18 patients in the test set, J48 and LMT methods were successful in 16 (89%) and 17 (94%) patients,respectively. The visual consensus readings were correct in all patients and SPM results were correct in 16 patients. The 5-fold crossvalidation method resulted in a mean correct lateralization ratio of 96% (47/49) for the LMT algorithm. This ratio was 88% (43 / 49) forthe J48 algorithm.Conclusion: Lateralization of the epileptogenic temporal lobe with data mining methods using regional metabolic asymmetry valuesobtained from interictal brain FDG PET images in mesial TLE patients is highly accurate. The application of data mining can contributeto the reader in the process of visual evaluation of FDG PET images of the brain.