Simultaneous EEG and functional MRI of epileptic activity: a case report

Objectives: Attempts to localize the source of epileptic activity by linking electroencephalographic (EEG) abnormalities to blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) signal alterations are hampered mainly by EEG distortions during MRI, subject motion, and unknown hemodynamic response characteristics. Methods: Using T2*-weighted echo-planar imaging at 2.0 T (2 s temporal resolution, 2×2×4 mm3 spatial resolution), this work demonstrates strategies to alleviate some of these problems while studying a patient who had ideopathic generalized epilepsy with poly-spike and slow-wave complexes. Results: Continuous EEG recordings during dynamic MRI (500 ms scanning, 1500 ms delay) and post-examination derivation of an EEG reference function for MRI analysis revealed positive BOLD MRI responses with temporal characteristics similar to those obtained for functional challenges. Conclusions: The ability to map focal epileptic activity and/or associated cognitive processing provides new potential for both epilepsy research and clinical patient management