Look back to leap forward: The emerging new role of magnetoencephalography (MEG) in nonlesional epilepsy

- MEG in the form of Magnetic Source Imaging (MSI) can increase the diagnostic yield of MRIs.
- MSI-guided re-review of supposedly negative MRIs may reveal significant pathology including focal cortical dysplasia (FCD).
- Clinical magnetoencephalographers (“MEG practitioners”) and the referring epilepsy teams (“MEG users”) should change their evaluation protocols accordingly.

This review considers accumulating evidence for a new role of MEG/MSI in increasing the diagnostic yield of supposedly negative MRIs, and suggests changes in the use of MEG/MSI in presurgical epilepsy evaluations. Specific alterations in practice protocols for both the MEG practitioner (i.e. physician magnetoencephalographer) and MEG user (i.e. referring physician) are proposed that should further enhance the overall value of MEG/MSI. Although advances in MEG analysis methods will likely become increasingly assisted by computers, interpretive competency and prudent clinical judgment remain irreplaceable.