This thesis describes the changes in cerebral morphology studied with magnetic resonance imaging (MRI) in two common forms of partial epilepsy, temporal lobe epilepsy (TLE) and frontal lobe epilepsy (FLE). In addition, the contribution of structural abnormalities to the observed distribution of fluorodeoxyglucose (FDG) in positron emission tomography (PET) was examined in patients with TLE. / In the first study, a quantitative morphological examination of the lateral temporal lobe in patients with mesial TLE is described. A significant reduction of white matter volume ipsilateral to the seizure focus and bilateral gray matter volume reduction were observed. In addition, abnormalities of the structure of the gray matter/CSF interface were found by surface curvature analysis. / The results of the first study raised the possibility that the apparently reduced uptake of FDG observed in interictal PET studies in TLE may in part be due to partial volume effects (PVE). The second study examines the contribution of volume loss and PVE to the asymmetry in the uptake of FDG seen in interictal PET. The results indicated that PVE contributes significantly to the observed asymmetry but does not explain it entirely. This suggests that additional metabolic or physiological factors are responsible for the observed abnormalities. / On the basis of the changes in white matter volume ipsilateral to the seizure focus, a loss of temporal lobe projection fibers resulting in local changes in the morphology of the corpus callosum at a site corresponding to the location of temporal crossover fibers was predicted. A method of detecting localized changes in the midsagittal corpus callosum was devised. Focal thinning in the corpus callosum was observed in patients with TLE compared to normal controls, supporting the biological significance of temporal lobe white matter changes in patients with TLE. The location of temporal lobe crossover fibers in the anterior to midbody of the corpus callosum was demonstrated. Progressive regional thinning of the anterior corpus callosum was demonstrated after temporal lobe resection in the same location as the thinning seen in TLE. / In the final study, the quantitative techniques developed in the previous morphometric studies of the cortex in TLE were applied to patients with FLE with normal MR images. White matter volume asymmetries corresponding to the clinical and electrographic lateralization of the site of seizure onset were observed in patients with normal MRI scans on visual inspection. These findings indicate that in patients with FLE, subtle structural lesions may be present despite a normal appearance on visual inspection of MR images. / In addition to their vital clinical role, neuroimaging techniques such as MRI and PET, are valuable research tools in the study of epilepsy. They yield a diverse range of biological information; in the studies describe, they have provided insight into aspects of the morphology of the normal brain and the structural changes of partial epilepsy.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.35465 |
| Date | January 1998 |
| Creators | Lee, Jong Woo, 1970- |
| Contributors | Reutens, David C. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Neurology and Neurosurgery.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001651833, proquestno: NQ50206, Theses scanned by UMI/ProQuest. |
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