title: Microstructural integrity of early- versus late-myelinating white matter tracts in medial temporal lobe epilepsy.
abstract: OBJECTIVE
  Patients with medial temporal lobe epilepsy (MTLE) exhibit structural brain damage involving gray matter (GM) and white matter (WM). The mechanisms underlying tissue loss in MTLE are unclear and may be associated with a combination of seizure excitotoxicity and WM vulnerability. The goal of this study was to investigate whether late-myelinating WM tracts are more vulnerable to injury in MTLE compared with early myelinating tracts.
  
  
  METHODS
  Diffusional kurtosis imaging scans were obtained from 25 patients with MTLE and from 36 matched healthy controls. Diffusion measures from regions of interest (ROIs) for both late- and early myelinating WM tracts were analyzed. Regional Z-scores were computed with respect to normal controls to compare WM in early myelinating tracts versus late-myelinating tracts.
  
  
  RESULTS
  We observed that late-myelinating tracts exhibited a larger decrease in mean, axial, and radial kurtosis compared with early myelinating tracts. We also observed that the change in radial kurtosis was more pronounced in late-myelinating tracts ipsilateral to the side of seizure onset.
  
  
  CONCLUSIONS
  These results suggest a developmentally based preferential susceptibility of late-myelinating WM tracts to damage in MTLE. Brain injury in epilepsy may be due to the pathologic effects of seizures in combination with regional WM vulnerability.
authors.affiliation: Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, U.S.A; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, U.S.A.
authors.forename: Chu-Yu
authors.initials: CY
authors.lastname: Lee
authors.forename: Ali
authors.initials: A
authors.lastname: Tabesh
authors.forename: Andreana
authors.initials: A
authors.lastname: Benitez
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Helpern
authors.forename: Jens H
authors.initials: JH
authors.lastname: Jensen
authors.forename: Leonardo
authors.initials: L
authors.lastname: Bonilha
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging; D004833:Epilepsy, Temporal Lobe / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology* / Q000502:physiology; D059906:Neuroimaging
keywords: Diffusion tensor imaging; Diffusional kurtosis imaging; MRI; Temporal lobe epilepsy; White matter tracts
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