title: Clinical added value of magnetic source imaging in the presurgical evaluation of refractory focal epilepsy.
abstract: OBJECTIVE
  This prospective, bicentre, blinded, intention to treat study assessed the clinical added value of magnetic source imaging (MSI) in the presurgical evaluation of patients with refractory focal epilepsy (RFE).
  
  
  METHODS
  70 consecutive patients with RFE (42 men; mean age 31.5 years, range 3-63) from two Belgian centres were prospectively included. All patients underwent conventional non-invasive presurgical evaluation (CNIPE) and a whole head magnetoencephalography recording (Elekta Neuromag). Equivalent current dipoles corresponding to interictal epileptiform discharges (IED) were fitted in the patients' spherical head model and coregistered on their MRI to produce MSI results. Results of CNIPE were first discussed blinded to the MSI results in respective multidisciplinary epilepsy surgery meetings to determine the presumed localisation of the epileptogenic zone and to set surgical or additional presurgical plans. MSI results were then discussed multidisciplinarily. MSI influence on the initial management plan was assessed.
  
  
  RESULTS
  Based on CNIPE, 21 patients had presumed extratemporal epilepsy, 38 had presumed temporal epilepsy and 11 had undetermined localisation epilepsy. MSI showed IED in 52 patients (74.5%) and changed the initial management in 15 patients (21%). MSI related changes were significantly more frequent in patients with presumed extratemporal or undetermined localisation epilepsy compared with patients with presumed temporal epilepsy (p≤0.001). These changes had a clear impact on clinical management in 13% of all patients.
  
  
  CONCLUSIONS
  MSI is a clinically relevant, non-invasive neuroimaging technique for the presurgical evaluation of patients with refractory focal epilepsy and, particularly, in patients with presumed extratemporal and undetermined localisation epilepsy.
authors.affiliation: Magnetoencephalography Unit, Laboratoire de Cartographiefonctionnelle du Cerveau, Université Libre de Bruxelles(ULB), Brussels, Belgium. xdetiege@ulb.ac.be
authors.forename: Xavier
authors.initials: X
authors.lastname: De Tiège
authors.forename: Evelien
authors.initials: E
authors.lastname: Carrette
authors.forename: Benjamin
authors.initials: B
authors.lastname: Legros
authors.forename: Kristl
authors.initials: K
authors.lastname: Vonck
authors.forename: Marc
authors.initials: M
authors.lastname: Op de Beeck
authors.forename: Mathieu
authors.initials: M
authors.lastname: Bourguignon
authors.forename: Nicolas
authors.initials: N
authors.lastname: Massager
authors.forename: Philippe
authors.initials: P
authors.lastname: David
authors.forename: Dirk
authors.initials: D
authors.lastname: Van Roost
authors.forename: Alfred
authors.initials: A
authors.lastname: Meurs
authors.forename: Samuel
authors.initials: S
authors.lastname: Lapere
authors.forename: Karel
authors.initials: K
authors.lastname: Deblaere
authors.forename: Serge
authors.initials: S
authors.lastname: Goldman
authors.forename: Paul
authors.initials: P
authors.lastname: Boon
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Bogaert
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000601:surgery; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D055815:Young Adult