Normative Volumetric Values of the Brainstem in Healthy Adults: Study of 3D Segmentation Technique

Authors : Ece Zeliha Büyükuysal, Gamze Taşkın Şenol, Sıddıka Halıcıoğlu

Pages : 827-836

Doi:10.35440/hutfd.1784162

View : 47 | Download : 133

Publication Date : 2025-12-25

Article Type : Research Paper

Abstract :Background: The brainstem is a critical center that connects the spinal cord with the brain and governs essential life functions. Its subdivisions-mesencephalon, pons, and medulla oblongata-play vital roles in regulating motor, sensory, and autonomic system functions. The morphological characteristics of these structures are of great importance for both neuroscientific research and clinical diagnostic and follow-up processes. The aim of this study is to compare the volumes of brainstem subregions in healthy individuals and to establish normative reference values. Materials and Methods: This retrospective study evaluated magnetic resonance images of 191 healthy individuals (105 females, 86 males) aged between 18 and 65 years, with no neurological disorders. The volumes of the mesencephalon, pons, and medulla oblongata were measured using manual segmentation via the ITK-SNAP software. The volumetric data obtained were analyzed both as absolute values and as proportions relative to the total brainstem volume, and normative reference ranges were determined. Results: The Friedman ranking test used for volumetric comparisons among the structures revealed statistically significant differences between the volumes of the mesencephalon, pons, and medulla oblongata (p<.001). Post hoc analyses indicated that the volume of the pons was significantly larger than that of both the mesencephalon and medulla oblongata. Analyses conducted using the Mann-Whitney U test showed no statistically significant differences between sexes in terms of mesencephalon, pons, and medulla oblongata volumes (p>.05). According to the Shapiro-Wilk test, the volumes of the mesencephalon and pons did not show normal distribution, whereas the medulla oblongata volume met the normality assumption. Conclusions: This study provides normative volumetric values and reference ranges for brainstem subregions in healthy individuals. The data obtained may serve as a comparative reference for understanding individual variation in brainstem anatomy and for aiding early diagnosis and monitoring of neurological disorders. Additionally, no significant sex-related differences were observed in the regional volume proportions within the total brainstem. These findings offer valuable reference data for neuroimaging-based clinical evaluations and make important contributions to basic science research.
Keywords : Mesencephalon, Pons, Medulla oblongata, ITK-SNAP

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