Changes of intrathoracic trachea with respiration in children : a metrical assessment based on 3D CT models

Aim: To assess the tracheal volume and the effect of respiration through segmentation on CT-scans in children. Material and methods: Chest-CT of 100 patients divided into males and females, aged 3–16 years, were retrospectively assessed. Subjects underwent inspiratory and expiratory CT-scans. Tracheal volume was segmented through ITK-SNAP software. Volume, length, anteroposterior, laterolateral diameters, and T1-T10 distance were measured. The percentage ratio between expiratory and inspiratory phases was calculated: significant differences according to sex for inspiratory and expiratory measurements were assessed through a one-way ANCOVA test using T1-T10 distance as covariate (p < 0.05). Differences in percentage changes according to sex and age were assessed through Mann-Whitney test and calculation of Pearson's correlation coefficient, respectively (p < 0.05). Results: No statistically significant difference according to sex was found for any measurement (p > 0.05). For the percentage ratio between inspiratory and expiratory phase, no difference was found according to sex for any measurement (p > 0.05). The percentage ratio of tracheal volume and length between expiratory and inspiratory phases showed a negative correlation with age (p < 0.05). Conclusions: This study provides a novel contribution to the assessment of tracheal size in healthy children: future studies will verify the same measurements in patients affected by tracheomalacia to improve diagnosis.