Morphometric Analysis of the Brainstem and Subarachnoid Cisterns Using Midsagittal MRI: A Retrospective Study

Abstract

This study aimed to evaluate comprehensively the morphometric characteristics of the brainstem and posterior fossa cisterns using midsagittal magnetic resonance imaging (MRI) and to investigate sex-related differences. A total of 200 adult participants aged 18 years and older (100 males, 100 females) were retrospectively included. High-resolution midsagittal T2-weighted MRI sequences were analyzed to measure the tentorial angle, clivus length, foramen magnum diameter, anteroposterior and superoinferior dimensions of brainstem segments, and the anteroposterior distances of the cisterna interpeduncularis, cisterna prepontis, cisterna magna, and cisterna quadrigeminalis. Data were analyzed using SPSS 28.0 with Mann–Whitney U and Spearman correlation tests. Females demonstrated greater tentorial angle and cerebellar height, whereas males exhibited larger mesencephalic and pontine dimensions as well as a wider interpeduncular cistern. No significant sex-related differences were observed in the remaining parameters. Correlation analysis revealed that the tentorial angle was positively associated with cerebellar height but negatively correlated with the widths of the interpeduncular and magna cisterns. Additional positive correlations were identified among brainstem segments and between posterior fossa cisterns. This study provides normative morphometric data on the brainstem and posterior fossa cisterns, offering reliable reference values for clinical and radiological assessments. The findings may contribute to improving diagnostic accuracy, refining surgical safety margins, and aiding in the differential diagnosis of pathological conditions. Furthermore, the data are expected to facilitate a more comprehensive anthropological evaluation of cranial morphology.

Keywords

• Brainstem
• Subarachnoid cisterns
• Posterior cranial fossa
• Cranial morphometry

Ethical Statement

This retrospective study was approved by the Non-Interventional Clinical Research Ethics Committee of Bilecik Şeyh Edebali University (Approval No: E-10333602-050.04-353763, Decision No: 7, Meeting No: 8, Date: August 27, 2025).

Thanks

We would like to thank the Radiology Department of Özel Nev Hospital for their kind assistance throughout the study.

Midsagittal Manyetik Rezonans Görüntüler Kullanılarak Beyin Sapı ve Subaraknoid Cisternaların Morfometrik Analizi: Retrospektif Bir Çalışma

Abstract

Bu çalışma, midsagittal manyetik rezonans (MR) görüntüleri kullanılarak beyin sapı ve posterior fossa cisternalarının morfometrik özelliklerini kapsamlı biçimde değerlendirmeyi ve cinsiyet farklılıklarını ortaya koymayı amaçlamaktadır. Retrospektif olarak planlanan araştırmaya 18 yaş ve üzeri 200 yetişkin bireyler (100 erkek, 100 kadın) dahil edildi. Yüksek çözünürlüklü midsagittal T2-ağırlıklı MRG kesitleri üzerinden tentorial açı, klivus uzunluğu, foramen magnum çapı, beyin sapı segmentlerinin anteroposterior ve superoinferior boyutları ile cisterna interpeduncularis, cisterna prepontis, cisterna magna ve cisterna quadrigeminalis’in anteroposterior mesafeleri ölçüldü. Veriler SPSS 28.0 programında Mann–Whitney U ve Spearman korelasyon testleri kullanılarak analiz edildi. Kadınlarda tentorial açı ve serebellum yüksekliği daha büyük bulunurken, erkeklerde mezensefalon ve pons boyutları ile cisterna interpeduncularis daha geniş ölçüldü. Diğer parametrelerde anlamlı cinsiyet farkı saptanmadı. Korelasyon analizinde, tentorial açının serebellum yüksekliği ile pozitif, cisterna interpeduncularis ve cisterna magna genişlikleri ile negatif ilişkili olduğu belirlendi. Ayrıca beyin sapı segmentleri arasında ve posterior fossa cisternaları arasında ek pozitif korelasyonlar saptandı. Bu çalışma, beyin sapı ve posterior fossa cisterna’larına ait normatif morfometrik veriler ortaya koyarak klinik ve radyolojik değerlendirmeler için güvenilir referans değerler sunmaktadır. Bulgular, tanısal doğruluğun artırılmasına, cerrahi güvenlik sınırlarının daha net tanımlanmasına ve patolojik durumların ayırıcı tanısına katkıda bulunabilir. Ayrıca, elde edilen verilerin kraniyal morfolojinin antropolojik açıdan daha kapsamlı değerlendirilmesine de olanak sağlayacağı öngörülmektedir.

Keywords

• Beyin sapı
• Subaraknoid cisternalar
• Posterior kranial fossa
• Kranial morfometri

Ethical Statement

Bu retrospektif çalışma, Bilecik Şeyh Edebali Üniversitesi Girişimsel Olmayan Klinik Araştırmalar Etik Kurulu tarafından onaylanmıştır (Onay No: E-10333602-050.04-353763, Karar No: 7, Toplantı No: 8, Tarih: 27 Ağustos 2025).

Thanks

Çalışma boyunca bize yardımcı olan Özel Nev Hastanesi Radyoloji Bölümü'ne teşekkür ederiz.

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