Three-dimensional morphometric analysis of paranasal sinuses and mastoid air cell system using computed tomography in pediatric population

Objectives: To evaluate the volumetric relationship between the mastoid air cell (MAC) and paranasal sinus (PNS) in the pediatric population using three-dimensional reconstruction and the analysis technique of CT.

Study design: Retrospective cross-sectional study was conducted at a university-based, secondary referral hospital.

Methods: PNS CT imaging data of 62 children (40 boys and 22 girls; mean age=13.4 ± 4.0 years) was reconstructed to the three-dimensional model with the surface-rendering algorithm (lower threshold of -1024 HU and upper threshold of -318 HU), and subsequently measuring the volume of the three PNSs (frontal, maxillary and sphenoid) and MAC. Hierarchical linear regression analysis was used to control the effect of age.

Results: Controlling the effect of age, no significant linear regression relationship was found between the volume of MAC and PNSs. It was observed that PNSs and MAC showed a significant linear relationship with age. The regression slopes of PNSs were larger than that of MAC, especially the growth of maxillary and sphenoid sinuses was faster and larger than that of the frontal sinus and MAC. As the coefficient of determination was extremely small, the aging process itself could not effectively explain the volume variation of PNSs and MAC.

Conclusion: No interaction was observed in the pneumatization of the three PNSs (frontal, maxillary, and sphenoid) and MAC. It was found that the growths of PNSs and MAC are influenced by age. Further, maxillary and sphenoid sinuses tend to grow faster and become larger than the frontal sinus and mastoid air cell system. Thus, it is verified that environmental factors could be involved in the postnatal pneumatization process of the PNSs and MAC, which might influence MAC to a greater extent than the PNSs.