3T versus 1.5T phased-array MRI in the presurgical work-up of patients with partial epilepsy of uncertain focus.
OBJECTIVE
To study 3T compared to 1.5T phased array magnetic resonance imaging (MRI) in the presurgical work-up of patients with epilepsy with complex focus localization.


METHODS
In all, 37 patients (>10 years) in preoperative work-up for epilepsy surgery were offered 3T in addition to 1.5T MRI if ambiguity existed about the epileptic focus. Scans were randomly reviewed by two observers, blinded for prior imaging, patient-identifying information, and each other's assessments, followed by a consensus meeting. The number of abnormal scans, detected lesions, and interobserver agreement were calculated and compared. The final consensus was compared to original scan reports.


RESULTS
One observer identified 22 lesions in both 3 and 1.5T scans, while the second identified more lesions in 1.5T scans (28 vs. 20). 3T MRI had better interobserver agreement. 3T revealed more dysplasias, while 1.5T revealed more tissue loss and mesial temporal sclerosis (MTS). The final consensus yielded 29 lesions, whereas original reports identified only 17 lesions.


CONCLUSIONS
The 3T scans revealed different lesions compared to 1.5T. Patients can benefit most from 3T scans when a dysplasia is suspected. Reevaluation by another experienced neuroradiologist is advised in case of negative or equivocal MRIs.
Zijlmans
Maeike
M
Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, The Netherlands. G.J.M.Zijlmans@umcutrecht.nl
de Kort
Gérard A P
GA
Witkamp
Theodore D
TD
Huiskamp
Geertjan M
GM
Seppenwoolde
Jan-Henry
JH
van Huffelen
Alexander C
AC
Leijten
Frans S S
FS
D000328:Adult; D001931:Brain Mapping / Q000379:methods; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015588:Observer Variation; D018579:Patient Selection