OC01 : The art of matchmaking: What is the link between findings in MRI and intraoperative electrocorticography in patients with focal epilepsy?. (March 2022)

• Record Type: Journal Article
• Authors: Straumann, S.; Schaft, E.; Noordmans, H.J.; Dankbaar, J.W.; Smits, P.; Zweiphenning, W.; Van Eijsden, P.; Mariani, L.; Van 't Klooster, M.; Zijlmans, M.
• Is Part Of: Clinical neurophysiology. Volume 135(2022)
• Page Start: e15
• Publication Date: 2022-03
• Subjects: Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2021.11.054
• Languages: English
• ISSNs: 1388-2457

Abstract

Abstract : Introduction: For 1.3-1.9 million patients suffering from drug-resistant focal epilepsy in Europe alone, neurosurgery is often the only path to seizure freedom. The delineation between healthy and epileptogenic tissue relies on MRI and other diagnostics and can be further refined through intraoperative electrocorticography (ioECoG). Complete removal of tissue generating interictal electric discharges (IEDs, <80Hz) and high frequency oscillations (HFOs, 80-500Hz) in ioECoG correlates with a good surgical outcome. The precise link between IEDs/HFOs and MRI lesions, however, is unknown. We aim to identify this link and improve our understanding of how ioECoG and MRI findings should be weighed against each other to accurately delineate epileptogentic tissue. Methods: We retrospectively included patients from the HFO Trial (Van 't Klooster, 2015) who underwent ioECoG-tailored surgery for a single lesion and achieved seizure freedom (Engel 1a). All lesions and resection cavities were segmented based on pre- and postoperative MRI scans. We automatically detected and visually verified IEDs and HFOs in 1-minute ioECoG epochs. Using intraoperative photographs, the MRI-coordinates of all ioECoG electrodes were determined on a rendering of the cortical surface. Results: 33 patients met our inclusion criteria. We will compare the number and rate of IEDs and HFOs per electrode with the volume of, and distance from the MRI lesion and subsequent resection cavity. We aim to find underlying functional relationships between those variables through regression analyses to better integrate MRI and ioECoG in our current model for tissue delineation. Conclusions: This study is ongoing, results are expected by mid-year 2021.