F161. Evolution of EEG-rfMRI bold activation maps during a focal seizure in a patient with medically refractory epilepsy

Abstract

Introduction Simultaneous EEG recordings during MRI have been used as a research tool to define the epileptogenic zone. Most of the data available has relied on MRI blood oxygenation level dependent signal (BOLD) changes during interictal spikes. The literature is limited regarding BOLD changes during ictal activity. We analyzed the BOLD activation maps during a focal onset electrographic seizure in a patient with medically refractory epilepsy. In addition, limited data is available regarding evolution of changes in functional connectivity maps compared to the resting state. Methods A patient with known medically refractory focal epilepsy underwent a resting fMRI-EEG study. Our protocol includes two twenty-minute resting state scanning sessions (3 T, Philips Ingenia) with simultaneous electroencephalography recorded with a Brain Vision fMRI EEG compatible system. Post-acquisition processing was performed to eliminate MRI artifact and EEG data was reviewed. A focal seizure was identified on EEG lasting approximately 6 min. The EEG was reviewed by 2 independent epileptologists who were in agreement regarding onset and duration of seizure. Twenty-four second blocks of rfMRI data were processed using AFNI (Analysis of Functional NeuroImages) program that corresponded to the identified seizure that was recorded with simultaneous EEG recordings. Sequential 12 s delays from onset were used to evaluate seizure propagation. Utilizing general linear model (GLM) fMRI Blood-Oxygen-Level Dependent (BOLD) activation maps were created. The differences in BOLD activation maps were compared to period of baseline fMRI recording when no EEG ictal or interictal changes were identified. Results Prior presurgical workup with video EEG monitoring in our patient demonstrated seizure onset in the left frontal region. High resolution 3T MRI was normal. rfMRI BOLD activation maps revealed focal changes in the left precentral gyrus. Seizure propagation was analyzed and images reviewed. Conclusion fMRI is widely available for evaluation of patients with epilepsy and is more readily available than other technologies such as MEG. As demonstrated by our patient, simultaneous EEG and fMRI recordings may be helpful in patients in defining the epileptogenic zone and planning for implantation and respective surgery.