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Published on: August 5, 2014
Detection of hippocampal atrophy in patients with temporal lobe epilepsy: a 3-Tesla MRI shape
Laura Mumoli1, Angelo Labate, Roberta Vasta
1Institute of Neurology, University Magna Græcia, Catanzaro, Italy.
Abstract:
In patients with mesial temporal lobe epilepsy (MTLE), brain MRI often detects hippocampal sclerosis (HS). Almost half of patients with MTLE do not show any hippocampal damage on visual or volumetric assessment. Here, we wished to prospectively assess 65 patients with MTLE (41 women, mean age: 39±10years, range: 21-69; right (12/65 patients) (MRI-negative) nMTLE; right (14/65 patients) (MRI-positive with HS) pMTLE; left (24/65 patients) nMTLE; and left (15/65 patients) pMTLE) using shape analysis (SA). There were significant differences among pMTLE versus nMTLE for age at seizure onset (20.2±12.8 vs. 31.8±16.7years; p=.0029), duration of epilepsy (14.6±12.7 vs. 21.3±9.6years; p=.0227), risk of refractoriness (p=.0067), frequency of antecedent febrile convulsions (FCs) (p<.001), as well as a history of epilepsy or FCs (p=.0104). All the subjects underwent the same 3-Tesla MRI protocol. Shape analysis of hippocampal formation was conducted comparing each group versus 44 matched controls. In all four subgroups, SA detected a significant atrophy in the corresponding hippocampus that coincided with the epileptogenic area. The damage was significantly more severe in patients with pMTLE (F value: 5.00) than in subgroups with nMTLE (F value: 3.50) and mainly corresponded to the CA1 subregion and subiculum. In the patients with MTLE, SA detects hippocampal damage that lateralizes with the epileptogenic area. Such damage is most prominent in the CA1 subregion and subiculum that are crucial in the pathogenesis of MTLE.
Insights
Shape analysis detects hippocampal damage in mesial temporal lobe epilepsy (MTLE) patients, even when MRI is negative. This damage, particularly in the CA1 subfield and subiculum, lateralizes with the seizure focus.
Area of Science:
- Neurology
- Radiology
- Neuroimaging
Background:
- Mesial temporal lobe epilepsy (MTLE) diagnosis often relies on detecting hippocampal sclerosis (HS) via MRI.
- However, nearly half of MTLE patients lack visible hippocampal damage on standard MRI assessments.
- Advanced imaging techniques are needed to identify subtle hippocampal abnormalities in MTLE.
Purpose of the Study:
- To prospectively evaluate the utility of shape analysis (SA) in detecting hippocampal damage in MTLE patients.
- To compare SA findings between MRI-negative (nMTLE) and MRI-positive with HS (pMTLE) MTLE subgroups.
- To investigate the lateralization and severity of hippocampal damage in relation to the epileptogenic area.
Main Methods:
- Sixty-five MTLE patients (nMTLE and pMTLE, left and right) and 44 controls underwent 3-Tesla MRI.
- Hippocampal formation shape analysis (SA) was performed for all groups.
- Clinical data including age at seizure onset, epilepsy duration, and history of febrile convulsions were collected.
Main Results:
- Shape analysis detected significant hippocampal atrophy in all four MTLE subgroups, correlating with the epileptogenic zone.
- Hippocampal damage was significantly more severe in pMTLE compared to nMTLE subgroups.
- Damage predominantly affected the CA1 subfield and subiculum, critical areas in MTLE pathogenesis.
Conclusions:
- Shape analysis is a sensitive tool for detecting hippocampal damage in MTLE, including in MRI-negative cases.
- The identified hippocampal atrophy lateralizes with the epileptogenic area in MTLE patients.
- The CA1 subfield and subiculum are key regions affected in the pathogenesis of MTLE.
