# APBA Kısa Özet

This case-control study utilized high-resolution three-dimensional T1-weighted MRI and VolBrain automated software to compare hippocampal and subfield volumes between 50 children with epilepsy and 50 age- and sex-matched healthy controls. In the epilepsy group, total hippocampal volume was significantly reduced compared to controls (4.10 ± 0.66 vs. 4.42 ± 0.87 cm³; p = 0.045), as was 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). 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. The research underscores the value of volumetric MRI for early MTLE diagnosis, while acknowledging limitations related to single-center recruitment, case-control design, and absence of long-term outcome data.

# Çalışma neyi araştırdı?

The primary objective was to evaluate the clinical value of MRI volumetric assessment of the hippocampus and its subfields for the early diagnosis of mesial temporal lobe epilepsy (MTLE) in children. Specifically, researchers aimed to determine whether volumetric analysis could detect structural abnormalities in children with MTLE who have normal conventional MRI findings (MRI-negative epilepsy). The study sought to identify specific hippocampal subfields most affected by volumetric changes in the pediatric epilepsy population.

# Yöntem

  • Tasarım: The study employed a single-center, case-control design.
  • Katılımcılar: A total of 100 children participated, comprising 50 children diagnosed with epilepsy (cases) and 50 age- and sex-matched healthy controls. Demographic variables, including age and sex distribution, were comparable between groups.
  • Görüntüleme Protokolü: All participants underwent high-resolution brain MRI using 3T scanners with three-dimensional T1-weighted imaging sequences. The imaging acquisition period spanned from January 2024 to July 2025 at the MRI Unit, Ain Shams University Hospitals, Cairo, Egypt.
  • Hacim Analizi: Hippocampal and hippocampal subfield volumes were automatically quantified using VolBrain software. The analysis included total hippocampal volume and specific subfields: CA1, CA2, CA3, CA4, dentate gyrus, and SR-SL-SM.
  • İstatistiksel Analiz: Group comparisons were performed using SPSS version 27. Statistical significance was set at p < 0.05. Results are presented as mean ± standard deviation (cm³).
  • Etik Onam: The study protocol was approved by the institutional ethics committee. Written informed consent was obtained from parents or guardians of all participating children.

# Temel bulgular

The key findings regarding hippocampal volumetry are summarized below:

| Ölçüm | Epilepsi Grubu (n=50) | Kontrol Grubu (n=50) | p‑değeri | |------|----------------|---------------|----------| | Toplam hippocampal hacim | 4.10 ± 0.66 cm³ | 4.42 ± 0.87 cm³ | 0.045 | | Sol hippocampal hacim | 2.03 ± 0.34 cm³ | 2.20 ± 0.41 cm³ | 0.034 | | Sağ hippocampal hacim | 2.07 ± 0.35 cm³ | 2.22 ± 0.44 cm³ | 0.089 | | SR‑SL‑SM alt‑bölüm | 0.75 ± 0.16 cm³ | 0.84 ± 0.17 cm³ | 0.006 |

Additionally, volumetric analysis identified hippocampal abnormalities in 34 out of 38 children (≈ 89%) who had normal conventional MRI findings, indicating a high detection rate for MRI-negative epilepsy.

# Bulgular ne anlama geliyor?

The volumetric reductions observed, particularly in the SR-SL-SM subfield, are indicative of microstructural changes associated with mesial temporal sclerosis (MTS), the most common pathological substrate of MTLE. The significant asymmetry, with the left hippocampus showing greater volume loss, aligns with the typical lateralization seen in MTLE. Most critically, the finding that volumetric analysis detected abnormalities in approximately 89% of children with MRI-negative epilepsy demonstrates that quantitative volumetric MRI substantially increases diagnostic sensitivity compared to conventional MRI alone. This suggests that hippocampal volumetry can serve as a non-invasive biomarker for early disease detection and characterization, potentially facilitating earlier clinical intervention.

# Klinik önem

  • Erken Tanı: Volumetric MRI enables the detection of hippocampal atrophy in the early stages of MTLE, even when conventional MRI appears normal. This early identification is crucial for initiating timely antiepileptic treatment and for planning surgical evaluation in children with drug-resistant epilepsy.
  • Tedavi ve Cerrahi Planlama: The localization of hippocampal volume loss (particularly left-sided and involving the SR-SL-SM subfield) provides valuable anatomical information that can guide surgical resection planning and neuromodulation strategies (e.g., responsive neurostimulation).
  • Görüntüleme Protokolü: Incorporating three-dimensional T1-weighted sequences and automated volumetric analysis into the standard pediatric epilepsy imaging protocol is a low-cost, high-yield addition. It enhances the diagnostic workflow without significantly increasing scan time or resource utilization.
  • Nöroloji ve Epilepsi Takibi: Objective volumetric measurements can be used over time to monitor disease progression or treatment response, although this study did not assess longitudinal outcomes.

Uyarı: While the results are promising, the study limitations must be considered. The case-control design precludes establishing causality, and the single-center sample limits the generalizability of findings to diverse pediatric populations. Furthermore, the automatic nature of VolBrain quantification, while efficient, may introduce variability not accounted for in inter-rater reliability studies.

# Sınırlılıklar

  1. Tasarım: The case-control nature of the study limits the ability to infer causal relationships; it establishes association but not causation between hippocampal volume loss and epilepsy.
  2. Tek Merkez: All data were collected from a single institution (Ain Shams University Hospitals, Egypt). Multi-center studies are required to validate these findings across different ethnic, geographic, and demographic cohorts.
  3. Otomatik Ölçüm: VolBrain software provides automated quantification; however, the report does not detail inter-rater variability or validation against manual tracing methods, leaving the precision of volume measurements open to interpretation.
  4. Klinik Takip: The study lacks long-term follow-up data regarding clinical outcomes, seizure frequency control, or surgical outcomes, limiting the assessment of the prognostic value of volumetric measurements.
  5. Genelleme: The study population primarily reflects children with MTLE. Findings may not be generalizable to other pediatric epilepsy syndromes or to adults.

APBA Yorum: This research represents a significant step forward in demonstrating the diagnostic utility of hippocampal volumetric assessment in pediatric MTLE, particularly for MRI-negative cases. However, it should not be used as the sole basis for clinical decision-making. Future prospective, multi-center studies with long-term follow-up are essential to confirm these findings and establish the definitive role of volumetric MRI in standard clinical practice for pediatric epilepsy.