Computed Tomographic Assessment of Nasal Anatomy in Healthy Iranian Infants: Establishing Population-Specific Norms

Objective: Normative morphometric data on infant nasal anatomy are essential for diagnosing congenital nasal pathologies and planning surgical or anesthetic interventions. However, existing studies are limited by small samples and insufficient ethnic diversity. Methods: In this cross-sectional study, computed tomography (CT) scans of 56 healthy Iranian infants (0-12 months) referred to Tabriz Children’s Hospital were retrospectively analyzed. Measurements included nasal length (NL), maximal septal length, piriform aperture (PA) dimensions, posterior bony nasal cavity (PBNC) width, and nasal bone indices. Age- and sex-based differences were assessed using correlation analysis and independent-sample t-tests. Results were compared with previously published normative datasets. Results: The mean PA area was 237.7 ± 77.5 mm2, with an inferior PA width of 13.4 ± 3.3 mm and PBNC width of 13.2 ± 2.5 mm. Strong positive correlations were observed between age and most nasal parameters, including NL (r = 0.84, P < .001) and PA area (r = 0.70, P = .011). Male infants had significantly larger PBNC widths and longer nasal bones than females (P < .05). Septal deviation was present in 11.9% of infants, and the trapezoid PA shape was the most common pattern. Compared with international data, Iranian infants showed narrower PAs and longer nasal bones, consistent with morphologic adaptations reported in populations from colder, drier climates. Conclusion: This study provides the first CT-based normative dataset for Iranian infants. The findings reveal important ethnic and climatic differences and highlight the need for population-specific reference values to improve diagnostic accuracy and guide pediatric radiologic and surgical decision-making.