Visualizing spikes in source-space: Rapid and efficient evaluation of magnetoencephalography

Area of Science:

• Neuroscience
• Medical Imaging
• Epileptology

Background:

• Magnetoencephalography (MEG) review is time-consuming, requiring evaluation of 306 sensors across multiple arrays.
• Traditional sensor-space review involves browsing each recording multiple times to assess all signals.
• Magnetocardiographic (MKG) artifacts can impede accurate signal evaluation.

Purpose of the Study:

• To evaluate the accuracy of a novel source-space reconstruction method for MEG signal review.
• To compare the efficiency and accuracy of source-space versus sensor-space MEG review.
• To assess the utility of source-space reconstruction in identifying epileptiform discharges.

Main Methods:

• A novel method reconstructing MEG signals in source-space using 29 brain regions and two spatial components was developed.
• Magnetocardiographic (MKG) artifacts were removed using spatial components.
• The accuracy of source-space review was prospectively evaluated against sensor-space review in 60 epilepsy patients.

Main Results:

• All 46 sensor-space identified spike-clusters were also found in source-space.
• Two additional spike-clusters were identified exclusively in source-space.
• Source-space review, displaying 29 channels simultaneously, reduced browsing time and enhanced epileptiform discharge detection due to MKG artifact suppression.

Conclusions:

• Reviewing MEG recordings in source-space is accurate and significantly faster than the classical sensor-space method.
• The novel source-space method facilitates clinical application of MEG.
• This approach enhances the detectability of epileptiform discharges by mitigating artifacts.