Age-Related CT Morphometry of the Pediatric Clivus and Dorsum Sellae: Cross-Sectional Changes and Pneumatization Patterns

Background/Objectives: This study investigated age-related morphometric and angular changes in the dorsum sellae and clivus, and evaluated dorsum sellae pneumatization patterns in a pediatric population using computed tomography (CT). Methods: This retrospective study included 720 pediatric subjects aged 0–18 years who underwent cranial CT. Subjects were stratified into five age groups. Four parameters were evaluated on multiplanar reformatted midsagittal images: clivus length, dorsum sellae middle thickness (ML-T), sphenoid–dorsal angle (SDA), and sellar–clival inclination angle (SCIA). Dorsum sellae pneumatization was classified into four types (Types 0–3) according to the criteria of Alpergin et al. Results: Clivus length increased with age, from 32.11 ± 5.65 mm in participants aged 0–2 years to 46.96 ± 3.67 mm in those aged 14–18 years. The SDA decreased from 103.49 ± 3.54° to 89.95 ± 9.86° and ML-T decreased from 3.95 ± 0.40 mm to 2.12 ± 0.61 mm. The SCIA differed between age groups but showed no consistent linear trend with age (r = −0.005, p = 0.884). In unadjusted comparisons, male subjects had a slightly greater clivus length. ML-T, SDA, and SCIA did not differ significantly between sexes. Following adjustment for age and the age × sex interaction, sex showed a weak association with ML-T (standardized β = 0.111, p = 0.007) but not with other morphometric parameters. Type 0 pneumatization was universal from 0 to 9 years of age. Pneumatization was observed in 48.6% of children aged 10–13 years and 34.0% in those aged 14–18 years; however, Type 2 and 3 patterns occurred exclusively in the 14–18-year group, indicating higher-grade pneumatization rather than a monotonic increase in overall prevalence. Conclusions: In this pediatric cohort, clivus length increased with age, whereas SDA and ML-T decreased. This study provides age group-specific descriptive morphometric data with excellent interobserver reproducibility; however, the findings should not be interpreted as normative reference standards.