title: MEG Coherence and DTI Connectivity in mTLE.
abstract: Magnetoencephalography (MEG) is a noninvasive imaging method for localization of focal epileptiform activity in patients with epilepsy. Diffusion tensor imaging (DTI) is a noninvasive imaging method for measuring the diffusion properties of the underlying white matter tracts through which epileptiform activity is propagated. This study investigates the relationship between the cerebral functional abnormalities quantified by MEG coherence and structural abnormalities quantified by DTI in mesial temporal lobe epilepsy (mTLE). Resting state MEG data was analyzed using MEG coherence source imaging (MEG-CSI) method to determine the coherence in 54 anatomical sites in 17 adult mTLE patients with surgical resection and Engel class I outcome, and 17 age- and gender- matched controls. DTI tractography identified the fiber tracts passing through these same anatomical sites of the same subjects. Then, DTI nodal degree and laterality index were calculated and compared with the corresponding MEG coherence and laterality index. MEG coherence laterality, after Bonferroni adjustment, showed significant differences for right versus left mTLE in insular cortex and both lateral orbitofrontal and superior temporal gyri (p < 0.017). Likewise, DTI nodal degree laterality, after Bonferroni adjustment, showed significant differences for right versus left mTLE in gyrus rectus, insular cortex, precuneus and superior temporal gyrus (p < 0.017). In insular cortex, MEG coherence laterality correlated with DTI nodal degree laterality ([Formula: see text] in the cases of mTLE. None of these anatomical sites showed statistically significant differences in coherence laterality between right and left sides of the controls. Coherence laterality was in agreement with the declared side of epileptogenicity in insular cortex (in 82 % of patients) and both lateral orbitofrontal (88 %) and superior temporal gyri (88 %). Nodal degree laterality was also in agreement with the declared side of epileptogenicity in gyrus rectus (in 88 % of patients), insular cortex (71 %), precuneus (82 %) and superior temporal gyrus (94 %). Combining all significant laterality indices improved the lateralization accuracy to 94 % and 100 % for the coherence and nodal degree laterality indices, respectively. The associated variations in diffusion properties of fiber tracts quantified by DTI and coherence measures quantified by MEG with respect to epileptogenicity possibly reflect the chronic microstructural cerebral changes associated with functional interictal activity. The proposed methodology for using MEG and DTI to investigate diffusion abnormalities related to focal epileptogenicity and propagation may provide a further means of noninvasive lateralization.
authors.affiliation: Research Administration, Henry Ford Health System, Detroit, MI, 48202, USA. mnazemz1@hfhs.org.
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Nazem-Zadeh
authors.affiliation: Neurology, Henry Ford Health System, Detroit, MI, 48202, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Bowyer
authors.affiliation: Neurology, Henry Ford Health System, Detroit, MI, 48202, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Moran
authors.affiliation: Research Administration, Henry Ford Health System, Detroit, MI, 48202, USA.
authors.forename: Esmaeil
authors.initials: E
authors.lastname: Davoodi-Bojd
authors.affiliation: Neurology, Henry Ford Health System, Detroit, MI, 48202, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Zillgitt
authors.affiliation: Institute of Cognitive Science University of Colorado Boulder, Boulder, CO, 80309, USA.
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Weiland
authors.affiliation: Research Administration, Henry Ford Health System, Detroit, MI, 48202, USA.|Departments of Radiation Oncology, Henry Ford Health System, Detroit, MI, 48202, USA.
authors.forename: Hassan
authors.initials: H
authors.lastname: Bagher-Ebadian
authors.affiliation: Research Administration, Henry Ford Health System, Detroit, MI, 48202, USA.|Computer and IT Engineering Faculty, Islamic Azad University, Qazvin Branch, Iran.
authors.forename: Fariborz
authors.initials: F
authors.lastname: Mahmoudi
authors.affiliation: Division of Neurosurgery, Department of Clinical Neurosciences, Spectrum Health System, Michigan State University, Grand Rapids, MI, 49503, USA.
authors.forename: Kost
authors.initials: K
authors.lastname: Elisevich
authors.affiliation: Research Administration, Henry Ford Health System, Detroit, MI, 48202, USA.|Control and Intelligent Processing Center of Excellence (CIPCE), School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Soltanian-Zadeh
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000503:physiopathology; D056324:Diffusion Tensor Imaging; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D007839:Functional Laterality; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000503:physiopathology; D013702:Temporal Lobe / Q000503:physiopathology; D055815:Young Adult
keywords: Coherence; Connectivity; Diffusion tensor imaging; Fiber tracts; Magnetoencephalography; Mesial temporal lobe epilepsy; Nodal degree