The Role of MRI Volumetric Assessment of Hippocampus and its Parts in Early Diagnosis of Mesial Temporal Lobe Epilepsy in Epileptic Children. A case-control study.

BACKGROUND

Mesial temporal lobe epilepsy (MTLE), commonly associated with mesial temporal sclerosis (MTS), is a major cause of drug-resistant epilepsy in children. Conventional magnetic resonance imaging (MRI) may fail to detect subtle hippocampal abnormalities, particularly in MRI-negative epilepsy. Quantitative MRI volumetric assessment has emerged as a promising method for identifying structural changes not evident on routine imaging.

OBJECTIVE

To evaluate the clinical value of MRI volumetric assessment of the hippocampus and its subfields for the early diagnosis of MTLE in children with epilepsy.

METHODS

This case-control study was conducted at the MRI Unit, Ain Shams University Hospitals, Cairo, Egypt, between January 2024 and July 2025. A total of 100 children (50 with epilepsy and 50 age- and sex-matched healthy controls) underwent high-resolution brain MRI with three-dimensional T1-weighted imaging. Hippocampal and hippocampal subfield volumes were automatically quantified using VolBrain software. Group comparisons were performed using SPSS version 27, with statistical significance set at p < 0.05.

RESULTS

The epilepsy and control groups were comparable in age and sex. Children with epilepsy had significantly lower total hippocampal volume (4.10 ± 0.66 vs. 4.42 ± 0.87 cm³; p = 0.045) and left hippocampal volume (2.03 ± 0.34 vs. 2.20 ± 0.41 cm³; p = 0.034). The SR-SL-SM subfield demonstrated the greatest volumetric reduction (0.75 ± 0.16 vs. 0.84 ± 0.17 cm³; p = 0.006), while the subiculum was also significantly smaller in the epilepsy group (0.48 ± 0.09 vs. 0.52 ± 0.11 cm³; p = 0.044). Among 38 children with normal conventional MRI findings, quantitative volumetric analysis identified hippocampal abnormalities in 34 cases, corresponding to a detection rate of approximately 89% for MRI-negative epilepsy.

CONCLUSION

MRI volumetric assessment is a valuable adjunct to conventional MRI for detecting subtle hippocampal and hippocampal subfield volume loss in children with epilepsy, including those with normal conventional MRI findings. Quantitative volumetric analysis may improve the detection of structural abnormalities associated with MTLE and supports its use as a complementary imaging tool in the diagnostic evaluation of pediatric epilepsy.