Related Experiment Videos
Longitudinal distribution of hippocampal atrophy in mesial temporal lobe epilepsy
M Quigg1, E H Bertram, T Jackson
1Health Sciences Center, Department of Neurology, Charlottesville, VA 22908, USA. quigg@virginia.edu
Abstract:
Patients with mesial temporal lobe epilepsy (MTLE) have asymmetric hippocampal volumes with atrophy that sometimes by visual inspection appears to favor different regions along the longitudinal axis of the affected hippocampus. Histological studies suggest that cell loss may affect the anterior hippocampus preferentially, and that hippocampal sclerosis (HS) limited to the anterior of the hippocampus may indicate better surgical outcome. We used volumetric magnetic resonance imaging (MRI): (1) to objectively describe the distribution of volume loss in HS; and (2) to relate this distribution to outcome of temporal lobectomy. Hippocampal volumes and anterior and posterior subvolumes (AHV, PHV) were measured from MP-RAGE MRI in 43 temporal lobectomy patients with MTLE determined by pathological findings of HS and compared to 23 age-matched controls. Atrophy was defined as 'anterior', 'diffuse', 'posterior', or 'normal' depending on position of AHV and PHV relative to the mean +/- 2 S.D. of regional volumes of control hippocampi. Anterior to posterior ratios (APR = AHV/PHV) were also calculated. Mean APR of hippocampi ipsilateral to lobectomy cannot be distinguished from hippocampi contralateral to lobectomy or from controls. AHV and PHV from hippocampi contralateral to temporal lobectomy were smaller than controls but larger than hippocampi ipsilateral to lobectomy. Surgical outcome was independent of longitudinal distribution of atrophy. We determined that overall volume loss in HS is diffuse, neither clearly favoring the head nor body-tail. Surgical outcome for MTLE is not related to the longitudinal distribution of atrophy revealed by volumetric MRI.
Insights
Mesial temporal lobe epilepsy (MTLE) patients show diffuse hippocampal volume loss, not localized to anterior or posterior regions. This pattern of hippocampal sclerosis (HS) does not predict surgical outcomes after temporal lobectomy.
Area of Science:
- Neurology
- Radiology
- Epilepsy Research
Background:
- Mesial temporal lobe epilepsy (MTLE) often involves hippocampal atrophy.
- Visual inspection of hippocampal sclerosis (HS) may suggest regional volume loss, potentially impacting surgical outcomes.
- Objective volumetric analysis is needed to characterize HS distribution and its relation to surgical success.
Purpose of the Study:
- To objectively quantify the distribution of hippocampal volume loss in HS using volumetric MRI.
- To investigate the relationship between the longitudinal distribution of atrophy and surgical outcomes in MTLE patients undergoing temporal lobectomy.
Main Methods:
- Volumetric MRI (MP-RAGE) was used to measure hippocampal volumes, including anterior (AHV) and posterior (PHV) subvolumes, in 43 MTLE patients with HS and 23 controls.
- Atrophy distribution was categorized as 'anterior', 'diffuse', or 'posterior' based on regional volumes relative to controls.
- Anterior to posterior ratios (APR) were calculated to assess longitudinal atrophy patterns.
Main Results:
- Hippocampal volume loss in HS was found to be diffuse, without a clear preference for anterior or posterior regions.
- Hippocampi contralateral to lobectomy showed reduced volume compared to controls but were larger than ipsilateral hippocampi.
- Surgical outcomes were not significantly correlated with the longitudinal distribution of hippocampal atrophy.
Conclusions:
- Overall hippocampal volume loss in HS is diffuse, challenging the notion of preferential anterior or posterior atrophy.
- The longitudinal distribution of atrophy in HS, as assessed by volumetric MRI, does not appear to be a predictor of surgical outcomes in MTLE.
- Further research may explore other factors influencing surgical success in MTLE.