Utilizing rs-fMRI’s Mean to Localize Seizure Focus

Purpose: We present for the first time the utilization of an average of the resting-state time points (rs-Mean) to localize epilepsy focus in a group of pediatric patients with medical refractory epilepsy. Materials and Methods: Twenty nine pediatric patients had drug-resistant epilepsy, and 22 subject controls underwent rs-fMRI. Comparison among group means was performed. Regions of Interest (ROI) derived from the nuclear medicine studies (GS) and the focal hyperintensities yielded by the rs-Mean were converted into ellipsoids. Euclidian Distance (ED) among the isocenters of each ROI pair per patient was found. Matching of ROIs was accepted if the ED was equal or less than 50 mm. Group comparison was performed utilizing two-tail T-test. Statistical significance was accepted with p values < 0.01. Results: Statistically significant differences were found between the patient and normal control’s rs-Mean (p < 0.001, t (49) = 5.186; CI (95%) = [512.73, 1161.46]). The rs-Mean findings matched the GS findings in epilepsy patients in 72.4% of cases. The rs-Mean was positive matching GS in 6 of 9 (66.6%) MR-non-lesional cases. Conclusion: Our study demonstrates that rs-Mean in intractable epilepsy patients differs from normal subjects, and that it may demonstrate the epileptogenic focus in a significant number of patients.