title: Yield of repeat routine MEG recordings in clinical practice.
abstract: From 377 consecutive MEG studies for patients with intractable epilepsy performed at the Cleveland Clinic between 2008 and 2011, 19 patients were referred for a repeat MEG. Source localization was done using a single equivalent current dipole (ECD) model on identified interictal spike activity. Clinical, neuroimaging, and concurrent EEG and MEG findings were reviewed. The most common reasons for repeating MEG were as follows: negative initial study in 6 patients, paucity of recorded interictal discharges in 4, failed surgeries in 3, uncertain findings in the first study in 2, and research-related reasons in 4. Repeat MEG provided new localizing findings in 11/19 patients (58%), of whom 6 had negative or rare interictal findings in the first study. Lobar concordance of dipoles was present in 6 (85%) of the 7 patients with positive findings in both MEG studies. This study demonstrates that a repeat MEG may provide new localization data when a previous recording shows limited or no interictal abnormalities.
authors.affiliation: Cleveland Clinic Epilepsy Center, 9500 Euclid Avenue, Cleveland, OH 44195, USA. mhdrafeed.alkawadri@yale.edu
authors.forename: Rafeed
authors.initials: R
authors.lastname: Alkawadri
authors.forename: Richard
authors.initials: R
authors.lastname: Burgess
authors.forename: Cigdem
authors.initials: C
authors.lastname: Isitan
authors.forename: Irene Z
authors.initials: IZ
authors.lastname: Wang
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kakisaka
authors.forename: Andreas V
authors.initials: AV
authors.lastname: Alexopoulos
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D002648:Child; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult