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Updated: Feb 27, 2026
Anteromesial Temporal Lobectomy for Medically Intractable Temporal Lobe Epilepsy: An Operative Study
Published on: August 15, 2025
Evaluation of ex-vivo 9.4T MRI in post-surgical specimens from temporal lobe epilepsy patients
Benjamin Y M Kwan1, Fateme Salehi1, Ryan Kope2
1Department of Medical Imaging, Schulich School of Medicine and Dentistry, Western University, 1151 Richmond St N, N6A 5B7, London, Ontario, Canada; Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, 1151 Richmond St, N6A 5B7 London, Ontario, Canada.
Purpose:
This study evaluates hippocampal pathology through usage of ultra-high field 9.4T ex-vivo imaging of resected surgical specimens in patients who have undergone temporal lobe epilepsy surgery.
Method And Materials:
This is a retrospective interpretation of prospectively acquired data. MRI scanning of resected surgical specimens from patients who have undergone temporal lobe epilepsy surgery was performed on a 9.4T small bore Varian MR magnet. Structural images employed a balanced steady-state free precession sequence (TrueFISP). Six patients (3 females; 3 males) were included in this study with an average age at surgery of 40.7 years (range 20Y_"60) (one was used as a control reference). Two neuroradiologists qualitatively reviewed the ex-vivo MRIs of resected specimens while blinded to the histopathology reports for the ability to identify abnormal features in hippocampal subfield structures.
Results:
The hippocampal subfields were reliably identified on the 9.4T ex-vivo scans in the hippocampal head region and hippocampal body region by both neuroradiologists in all 6 patients. There was high concordance to pathology for abnormalities detected in the CA1, CA2, CA3 and CA4 subfields. Detection of abnormalities in the dentate gyrus was also high with detection in 4 of 5 cases. The Cohen's kappa between the two neuroradiologists was calculated at 0.734 SE=0.102.
Conclusions:
Ex-vivo 9.4T specimen imaging can detect abnormalities in CA1, CA2, CA3, CA4 and DG in both the hippocampal head and body. There was good concordance between qualitative findings and histopathological abnormalities for CA1, CA2, CA3, CA4 and DG.
Insights
Ultra-high field 9.4T ex-vivo imaging effectively identifies hippocampal pathology in epilepsy surgery specimens. This advanced MRI technique shows high concordance with histopathology for detecting abnormalities in key hippocampal subfields.
Area of Science:
- Neuroimaging
- Epilepsy Research
- Pathology
Background:
- Temporal lobe epilepsy surgery involves resecting brain tissue, including the hippocampus.
- Accurate pathological assessment of resected specimens is crucial for understanding epilepsy.
- Advanced imaging techniques can potentially enhance the analysis of surgical specimens.
Purpose of the Study:
- To evaluate the utility of ultra-high field 9.4T ex-vivo MRI for assessing hippocampal pathology.
- To determine the ability of 9.4T MRI to identify abnormalities in specific hippocampal subfields.
- To compare MRI findings with histopathological reports.
Main Methods:
- Retrospective analysis of prospectively acquired data from six epilepsy surgery patients.
- Ex-vivo MRI of resected hippocampal specimens using a 9.4T magnet and TrueFISP sequence.
- Qualitative review of MRI scans by two neuroradiologists blinded to histopathology.
Main Results:
- Reliable identification of hippocampal subfields (CA1-CA4, dentate gyrus) in the hippocampal head and body.
- High concordance between 9.4T MRI findings and histopathological abnormalities in CA1-CA4 and dentate gyrus.
- Excellent inter-rater reliability (Cohen's kappa = 0.734) between neuroradiologists.
Conclusions:
- Ex-vivo 9.4T MRI is a valuable tool for detecting hippocampal abnormalities in epilepsy surgery specimens.
- The technique demonstrates high accuracy in identifying pathological changes in key hippocampal subfields.
- This imaging approach offers a promising method for detailed neuropathological evaluation in epilepsy.
