A comparison of magnetoencephalography, MRI, and V-EEG in patients evaluated for epilepsy surgery.
OBJECTIVE
To determine the efficacy and relative contribution of several diagnostic methods [ictal and interictal scalp and intracranial EEG, magnetic resonance imaging (MRI), and magnetoencephalography (MEG)] in identifying the epileptogenic zone for resection.


METHODS
This was a prospective study using a masked comparison-to-criterion standard. Fifty-eight consecutive patients with refractory partial epilepsy from two university comprehensive epilepsy programs were studied. Patients who were evaluated for and underwent epilepsy surgery were recruited. The main outcome measure was the efficacy of each diagnostic method to identify the resected epileptogenic zone, when referenced to surgical outcome.


RESULTS
MEG (52%) was second only to ictal intracranial V-EEG in predicting the epileptogenic zone for the entire group of patients who had an excellent surgical outcome (seizure free or rare seizure). In a subanalysis, for patients who had temporal lobe surgery, this same relation was seen (MEG, 57%, ictal intracranial V-EEG, 62%). With extratemporal resection, ictal (81%) and interictal (75%) intracranial EEG were superior to MEG (44%) in predicting the surgery site in those patients with an excellent outcome. Finally, for all patients who had a good surgical outcome, MEG (52%) was better than ictal (33%) or interictal (45%) scalp VEEG in predicting the site of surgery.


CONCLUSIONS
These results indicate that MEG is a very promising diagnostic method and raise the possibility that it may obviate the need for invasive EEG in some cases or reduce the length of scalp EEG evaluation in others.
University of Texas-Houston, Texas Comprehensive Epilepsy Program, 77030, USA.
J W
JW
Wheless
L J
LJ
Willmore
J I
JI
Breier
M
M
Kataki
J R
JR
Smith
D W
DW
King
K J
KJ
Meador
Y D
YD
Park
D W
DW
Loring
G L
GL
Clifton
J
J
Baumgartner
A B
AB
Thomas
J E
JE
Constantinou
A C
AC
Papanicolaou
D000293:Adolescent; D000328:Adult; D002648:Child; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D014743:Videotape Recording