Lateralizing Morphometric feature Changes to Hippocampus and Amygdala in unilateral TLE patients
Poster No:
1488
Submission Type:
Abstract Submission
Authors:
Jeongsik Kim1, Young-Min Shon2
Institutions:
1Samsung Medical Center, Seoul, Seoul, 2Samsung medical center, Seoul, Seoul
First Author:
Co-Author:
Introduction:
Hippocampal sclerosis (HS) is a common pathology observed in mesial temporal lobe epilepsy (TLE) and other epilepsy syndromes. The MRI features of HS include atrophy and/or high signal intensity of the hippocampus (HC) on T2-weighted (T2WI) and fluid-attenuated inversion recovery (FLAIR) images. However, hippocampal volume alone is not a reliable predictor of postsurgical outcomes in patients with mesial TLE with HS (TLE-HS). (Blumcke, 2013; Leemput, 2009)
This study aimed to determine which subfield volume is related to specific clinical features of TLE-HS through automatic subfield volume measurements using HSV. It also attempted to determine whether these associations showed different characteristics according to the lateralization of the seizure focus.
This study aimed to determine which subfield volume is related to specific clinical features of TLE-HS through automatic subfield volume measurements using HSV. It also attempted to determine whether these associations showed different characteristics according to the lateralization of the seizure focus.
Methods:
Mesial TLE (MTLE) with HS patients were recruited among patients who were admitted for video-EEG monitoring. The study included 48 MTLE patients with confirmed unilateral HS on brain MRI, including 22 patients with left-sided MTLE-HS (LTLE-HS) and 26 patients with right-sided MTLE-HS (RTLE-HS). This study included 28 healthy controls without abnormal findings on neurological examination or brain MRI.
For each patient, T1-weighted MRI volume was preprocessed using the standard FreeSurfer recon-all pipeline (version 7.0) for quantitative automated analyses (segmentation, volume parcellation, and Hippocampal subfield and AMG nuclei volume estimates).
All statistical analyses were performed using the SPSS version 21.0 (SPSS Inc., Chicago, IL, USA).
Group comparisons were performed using the independent sample t-test (normally distributed data, p < 0.05) or unpaired Mann–Whitney U test (data not normally distributed, p < 0.05).
For each patient, T1-weighted MRI volume was preprocessed using the standard FreeSurfer recon-all pipeline (version 7.0) for quantitative automated analyses (segmentation, volume parcellation, and Hippocampal subfield and AMG nuclei volume estimates).
All statistical analyses were performed using the SPSS version 21.0 (SPSS Inc., Chicago, IL, USA).
Group comparisons were performed using the independent sample t-test (normally distributed data, p < 0.05) or unpaired Mann–Whitney U test (data not normally distributed, p < 0.05).
Results:
The detailed demographic information is presented in Table 1.
Overall, HC and AMG mean subfield volumes were smaller in patients than in controls. In both groups, the mean z-scores of the subfield volumes on the ipsilateral side were smaller than those on the contralateral side. Patients with LTLE-HS had significantly reduced volumes of the ipsilateral SUB head, contralateral SUB head, and ipsilateral Co compared with patients with RTLE-HS. Furthermore, RTLE-HS patients had significantly reduced volumes of the ipsilateral CA2/3 head and contralateral CAT compared to LTLE-HS patients.
In both patients with LTLE-HS and RTLE-HS, the epilepsy duration was significantly correlated with hippocampal subfield volumes. In the LTLE-HS group, the volumes of the ipsilateral CA1 head, CA1, CA4 head, and DG head were negatively correlated with epilepsy duration. In RTLE-HS, all subfield volumes on the ipsilateral side were negatively correlated with epilepsy duration (Table 2).
In LTLE-HS, onset age was positively correlated with ipsilateral Ce and Me volumes, and epilepsy duration was negatively correlated with the volumes of the ipsilateral Ce and Me. The subfield volumes of AMG and the frequencies of focal aware seizures(FAS) and focal impaired aware seizures(FIAS) were not correlated in patients with LTLE-HS.
In RTLE-HS, the epilepsy duration was negatively correlated with the volumes of the ipsilateral Me and Co, and the frequency of FAS was positively correlated with the volume of the ipsilateral Me (Table 2). Age at epilepsy onset and frequency of FIAS were not associated with AMG subfield volumes in patients with RTLE-HS.
Overall, HC and AMG mean subfield volumes were smaller in patients than in controls. In both groups, the mean z-scores of the subfield volumes on the ipsilateral side were smaller than those on the contralateral side. Patients with LTLE-HS had significantly reduced volumes of the ipsilateral SUB head, contralateral SUB head, and ipsilateral Co compared with patients with RTLE-HS. Furthermore, RTLE-HS patients had significantly reduced volumes of the ipsilateral CA2/3 head and contralateral CAT compared to LTLE-HS patients.
In both patients with LTLE-HS and RTLE-HS, the epilepsy duration was significantly correlated with hippocampal subfield volumes. In the LTLE-HS group, the volumes of the ipsilateral CA1 head, CA1, CA4 head, and DG head were negatively correlated with epilepsy duration. In RTLE-HS, all subfield volumes on the ipsilateral side were negatively correlated with epilepsy duration (Table 2).
In LTLE-HS, onset age was positively correlated with ipsilateral Ce and Me volumes, and epilepsy duration was negatively correlated with the volumes of the ipsilateral Ce and Me. The subfield volumes of AMG and the frequencies of focal aware seizures(FAS) and focal impaired aware seizures(FIAS) were not correlated in patients with LTLE-HS.
In RTLE-HS, the epilepsy duration was negatively correlated with the volumes of the ipsilateral Me and Co, and the frequency of FAS was positively correlated with the volume of the ipsilateral Me (Table 2). Age at epilepsy onset and frequency of FIAS were not associated with AMG subfield volumes in patients with RTLE-HS.
·Table 1. Patient characteristics.
·Table 2. Correlation between subfield volumes and clinical variables.
Conclusions:
The results indicate that unilateral TLE-HS is a bilateral disease that shows different laterality-dependent characteristics based on the subfield analysis of HC and AMG. Subfield volumes of HC and AMG were associated with clinical variables, and the more damaged substructures depended on laterality in TLE-HS. These findings support the evidence that LTLE-HS and RTLE-HS are disparate epilepsy entities rather than simply identical syndromes harboring a mesial temporal lesion. In addition, the presence of FAS supports good localization value, and abdominal FAS has a high localization value, especially in patients with LTLE-HS.
Modeling and Analysis Methods:
Image Registration and Computational Anatomy 1
Segmentation and Parcellation 2
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Subcortical Structures
Novel Imaging Acquisition Methods:
Anatomical MRI
Keywords:
Epilepsy
Morphometrics
Segmentation
STRUCTURAL MRI
Other - hippocampal subfield analysis
1|2Indicates the priority used for review
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Provide references using APA citation style.
Leemput, K.V. (2009). Automated segmentation of hippocampal subfields from ultra-high resolution in vivo MRI. Hippocampus. 19, 549–557.