title: Quantitative relaxometry and diffusion MRI for lateralization in MTS and non-MTS temporal lobe epilepsy.
abstract: We developed novel methodology for investigating the use of quantitative relaxometry (T1 and T2) and diffusion tensor imaging (DTI) for lateralization in temporal lobe epilepsy. Patients with mesial temporal sclerosis confirmed by pathology (N=8) and non-MTS unilateral temporal lobe epilepsy (N=6) were compared against healthy controls (N=19) using voxel-based analysis restricted to the anterior temporal lobes, and laterality indices for each MRI metric (T1, T2, fractional anisotropy (FA), mean diffusivity, axial and radial diffusivities) were computed based on the proportion of significant voxels on each side. The diffusivity metrics were the most lateralizing MRI metrics in MTS and non-MTS subsets, with significant differences also seen with FA, T1 and T2. Patient-specific multi-modal laterality indices were also computed and were shown to clearly separate the left-onset and right-onset patients. Marked differences between left-onset and right-onset patients were also observed, with left-onset patients exhibiting stronger laterality indices. Finally, neocortical abnormalities were found to be more common in the non-MTS patients. These preliminary results on a small sample size support the further investigation of quantitative MRI and multi-modal image analysis in clinical determination of seizure onset. The presence of more neocortical abnormalities in the non-MTS group suggests a role in seizure onset or propagation and motivates the investigation of more sensitive histopathological analysis to detect and delineate potentially subtle neocortical pathology.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada. Electronic address: alik@robarts.ca.
authors.forename: Ali R
authors.initials: AR
authors.lastname: Khan
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada; Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada.
authors.forename: Maged
authors.initials: M
authors.lastname: Goubran
authors.affiliation: Department of Medical Biophysics, Western University, London, Ontario, Canada; Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada; Epilepsy Program, Department of Clinical Neurological Sciences, Western University & London Health Science Centre, London, Ontario, Canada.
authors.forename: Sandrine
authors.initials: S
authors.lastname: de Ribaupierre
authors.affiliation: Department of Pathology, Division of Neuropathology, Western University & London Health Science Centre, London, Ontario, Canada.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Hammond
authors.affiliation: Epilepsy Program, Department of Clinical Neurological Sciences, Western University & London Health Science Centre, London, Ontario, Canada.
authors.forename: Jorge G
authors.initials: JG
authors.lastname: Burneo
authors.affiliation: Epilepsy Program, Department of Clinical Neurological Sciences, Western University & London Health Science Centre, London, Ontario, Canada.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Parrent
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada.
authors.forename: Terry M
authors.initials: TM
authors.lastname: Peters
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging; D004833:Epilepsy, Temporal Lobe / Q000150:complications* / Q000601:surgery; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D012598:Sclerosis / Q000209:etiology / Q000473:pathology; D013702:Temporal Lobe / Q000473:pathology*; D055815:Young Adult
keywords: Diffusion tensor imaging; MRI-negative; Paradoxical TLE; Quantitative relaxometry; Voxel-based analysis