Concomitant Fractional Anisotropy and Volumetric Abnormalities in Temporal Lobe Epilepsy: Cross-Sectional Evidence for Progressive Neurologic Injury
Open Access
- 11 October 2012
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 7 (10), e46791
- https://doi.org/10.1371/journal.pone.0046791
Abstract
In patients with temporal lobe epilepsy and associated hippocampal sclerosis (TLEhs) there are brain abnormalities extending beyond the presumed epileptogenic zone as revealed separately in conventional magnetic resonance imaging (MRI) and MR diffusion tensor imaging (DTI) studies. However, little is known about the relation between macroscopic atrophy (revealed by volumetric MRI) and microstructural degeneration (inferred by DTI). For 62 patients with unilateral TLEhs and 68 healthy controls, we determined volumes and mean fractional anisotropy (FA) of ipsilateral and contralateral brain structures from T1-weighted and DTI data, respectively. We report significant volume atrophy and FA alterations of temporal lobe, subcortical and callosal regions, which were more diffuse and bilateral in patients with left TLEhs relative to right TLEhs. We observed significant relationships between volume loss and mean FA, particularly of the thalamus and putamen bilaterally. When corrected for age, duration of epilepsy was significantly correlated with FA loss of an anatomically plausible route - including ipsilateral parahippocampal gyrus and temporal lobe white matter, the thalamus bilaterally, and posterior regions of the corpus callosum that contain temporal lobe fibres - that may be suggestive of progressive brain degeneration in response to recurrent seizures. Chronic TLEhs is associated with interrelated DTI-derived and volume-derived brain degenerative abnormalities that are influenced by the duration of the disorder and the side of seizure onset. This work confirms previously contradictory findings by employing multi-modal imaging techniques in parallel in a large sample of patients.Keywords
This publication has 83 references indexed in Scilit:
- Volume Estimation of the Thalamus Using Freesurfer and Stereology: Consistency between MethodsNeuroinformatics, 2012
- MRI analysis in temporal lobe epilepsy: Cortical thinning and white matter disruptions are related to side of seizure onsetEpilepsia, 2011
- Hippocampal Sclerosis in Temporal Lobe Epilepsy: Findings at 7 TRadiology, 2011
- Reliability and validity of MRI-based automated volumetry software relative to auto-assisted manual measurement of subcortical structures in HIV-infected patients from a multisite studyNeuroImage, 2010
- Hippocampal volume assessment in temporal lobe epilepsy: How good is automated segmentation?Epilepsia, 2009
- Longitudinal and cross-sectional analysis of atrophy in pharmacoresistant temporal lobe epilepsyNeurology, 2009
- A comparison of automated segmentation and manual tracing for quantifying hippocampal and amygdala volumesNeuroImage, 2009
- Diffusion tensor imaging of deep gray matter brain structures: Effects of age and iron concentrationNeurobiology of Aging, 2008
- Temporal-callosal pathway diffusivity predicts phonological skills in childrenProceedings of the National Academy of Sciences of the United States of America, 2007
- Asymmetrical extra-hippocampal grey matter loss related to hippocampal atrophy in patients with medial temporal lobe epilepsyJournal of Neurology, Neurosurgery & Psychiatry, 2006