Verification of dipole fit source localization in patients with epilepsy using postoperative MRI

ABSTRACT

@#Objective: Dipole fit source (DFS) localisation is a non-invasive imaging process used to identify the epileptogenic zone (EZ) in the brain. The purpose of the present study was to verify the use of DFS localisation for identifying the EZ in patients with and without lesions using magnetic resonance imaging (MRI). Methods: In this study, DFS localisation was used in 16 patients, of whom 7 had no lesions and 9 had lesions on MRI post-surgery, with at least 3 years of follow-up data. For DFS localisation, different scalp electroencephalogram (EEG) ictal activity was assessed (ictal spikes, rhythmic, paroxysmal fast, and obscured activity). DFSs were superimposed with postoperative MRIs to confirm the accuracy of the determined EZs. Results: The DFS correctly identified EZ localization within the resection area in 14 of the 16 patients. These 14 patients were all seizure free after surgery. The two remaining patients, in whom the DFS was adjacent to the resected area, had a decreased seizure frequency following surgery.Conclusions: DFSs determined during preoperative evaluations can provide information on EZ lateralisation and localisation and contribute to the presurgical decision process. Thus, the accurate identification of EZ boundaries is important and can be achieved more reliably with the use of multiple quantitative EEG analysis methods.