Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy
Abstract Objective Hippocampal sclerosis (HS) is the most common pathology and best predictor of surgical outcome for medically refractory patients with temporal lobe epilepsy (TLE). Current clinical MRI methods can detect HS, but subfield pathology is poorly characterized, limiting accurate predict...
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doaj-59bd4df684ab485b9c0c60307c415b622020-11-25T01:29:30ZengWileyEpilepsia Open2470-92392019-12-014454455410.1002/epi4.12357Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsySarah Treit0Graham Little1Trevor Steve2Tom Nowacki3Laura Schmitt4B. Matt Wheatley5Christian Beaulieu6Donald W. Gross7Department of Biomedical Engineering Faculty of Medicine and Dentistry University of Alberta Edmonton CanadaDepartment of Biomedical Engineering Faculty of Medicine and Dentistry University of Alberta Edmonton CanadaDivision of Neurology Faculty of Medicine & Dentistry University of Alberta Edmonton CanadaDivision of Neurology Faculty of Medicine & Dentistry University of Alberta Edmonton CanadaDepartment of Laboratory Medicine and Pathology Faculty of Medicine and Dentistry University of Alberta Edmonton CanadaDepartment of Surgery Faculty of Medicine and Dentistry University of Alberta Edmonton CanadaDepartment of Biomedical Engineering Faculty of Medicine and Dentistry University of Alberta Edmonton CanadaDivision of Neurology Faculty of Medicine & Dentistry University of Alberta Edmonton CanadaAbstract Objective Hippocampal sclerosis (HS) is the most common pathology and best predictor of surgical outcome for medically refractory patients with temporal lobe epilepsy (TLE). Current clinical MRI methods can detect HS, but subfield pathology is poorly characterized, limiting accurate prediction of seizure‐free outcomes after surgery. Diffusion tensor imaging (DTI) can probe regional microstructural changes associated with focal hippocampal pathology, but is typically limited by low‐resolution whole‐brain acquisitions. Methods High‐resolution (1 × 1 × 1 mm3) DTI, T1, and quantitative T2 of the hippocampus was acquired in 18 preoperative TLE patients and 19 healthy controls. Diffusion images were qualitatively assessed for loss of internal architecture, and whole‐hippocampus diffusion, volume, and quantitative T2 were compared across groups. Regional hippocampal diffusion abnormalities were examined in all subjects and compared to histology in four subjects who underwent anterior temporal lobectomy. Results High‐resolution mean diffusion‐weighted images enabled visualization of internal hippocampal architecture, used to visually identify HS with 86% specificity and 93% sensitivity. Mean diffusivity (MD) elevations were regionally heterogenous within the hippocampus and varied across TLE patients. The spatial location of diffusion abnormalities corresponded with the location of focal subfield neuron loss, gliosis, and reduced myelin staining abnormalities identified with postsurgical histology in four subjects who underwent anterior temporal lobectomy. Whole‐hippocampus MD and T2 relaxation times were higher, and fractional anisotropy (FA) and volumes were lower in TLE patients relative to controls. Left hippocampus MD correlated with verbal memory in the TLE group. Significance Visualization of internal architecture and focal diffusion abnormalities on high‐resolution diffusion imaging suggests potential clinical utility of diffusion imaging in TLE and may have significant implications for surgical planning and prediction of seizure‐free outcomes in individual patients.https://doi.org/10.1002/epi4.12357hippocampal sclerosishistologymean diffusivitymemorytemporal lobe epilepsy |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Sarah Treit Graham Little Trevor Steve Tom Nowacki Laura Schmitt B. Matt Wheatley Christian Beaulieu Donald W. Gross |
spellingShingle |
Sarah Treit Graham Little Trevor Steve Tom Nowacki Laura Schmitt B. Matt Wheatley Christian Beaulieu Donald W. Gross Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy Epilepsia Open hippocampal sclerosis histology mean diffusivity memory temporal lobe epilepsy |
author_facet |
Sarah Treit Graham Little Trevor Steve Tom Nowacki Laura Schmitt B. Matt Wheatley Christian Beaulieu Donald W. Gross |
author_sort |
Sarah Treit |
title |
Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy |
title_short |
Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy |
title_full |
Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy |
title_fullStr |
Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy |
title_full_unstemmed |
Regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy |
title_sort |
regional hippocampal diffusion abnormalities associated with subfield‐specific pathology in temporal lobe epilepsy |
publisher |
Wiley |
series |
Epilepsia Open |
issn |
2470-9239 |
publishDate |
2019-12-01 |
description |
Abstract Objective Hippocampal sclerosis (HS) is the most common pathology and best predictor of surgical outcome for medically refractory patients with temporal lobe epilepsy (TLE). Current clinical MRI methods can detect HS, but subfield pathology is poorly characterized, limiting accurate prediction of seizure‐free outcomes after surgery. Diffusion tensor imaging (DTI) can probe regional microstructural changes associated with focal hippocampal pathology, but is typically limited by low‐resolution whole‐brain acquisitions. Methods High‐resolution (1 × 1 × 1 mm3) DTI, T1, and quantitative T2 of the hippocampus was acquired in 18 preoperative TLE patients and 19 healthy controls. Diffusion images were qualitatively assessed for loss of internal architecture, and whole‐hippocampus diffusion, volume, and quantitative T2 were compared across groups. Regional hippocampal diffusion abnormalities were examined in all subjects and compared to histology in four subjects who underwent anterior temporal lobectomy. Results High‐resolution mean diffusion‐weighted images enabled visualization of internal hippocampal architecture, used to visually identify HS with 86% specificity and 93% sensitivity. Mean diffusivity (MD) elevations were regionally heterogenous within the hippocampus and varied across TLE patients. The spatial location of diffusion abnormalities corresponded with the location of focal subfield neuron loss, gliosis, and reduced myelin staining abnormalities identified with postsurgical histology in four subjects who underwent anterior temporal lobectomy. Whole‐hippocampus MD and T2 relaxation times were higher, and fractional anisotropy (FA) and volumes were lower in TLE patients relative to controls. Left hippocampus MD correlated with verbal memory in the TLE group. Significance Visualization of internal architecture and focal diffusion abnormalities on high‐resolution diffusion imaging suggests potential clinical utility of diffusion imaging in TLE and may have significant implications for surgical planning and prediction of seizure‐free outcomes in individual patients. |
topic |
hippocampal sclerosis histology mean diffusivity memory temporal lobe epilepsy |
url |
https://doi.org/10.1002/epi4.12357 |
work_keys_str_mv |
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