Quantitative CT measurements of segmental bronchial changes during inspiratory and expiratory phases in healthy subjects.

Background: Recently, the quantitative measurement of the bronchi has gained attention due to its importance in understanding respiratory function and its application in diseases such as asthma and chronic obstructive pulmonary disease (COPD). The accurate measurement of bronchial changes in healthy individuals provides valuable baseline data for comparison in clinical practice.

Objectives: This study aims to quantitatively assess changes in segmental bronchial diameter and lumen area during inspiratory and expiratory phases.

Methods: A cross-sectional study of 68 healthy subjects was conducted. The inspiratory and expiratory phases of the whole lung were scanned using low-dose Multi-slice CT (MSCT). The apical segment of the right superior lobe (RB1), medial segment of the right middle lobe (RB5), posterior basal segment of the right lower lobe (RB10), apicoposterior segment of the left superior lobe (LB(1+2)), inferior lingular segment of the left lower lobe (LB5), and posterior basal segment of the left lower lobe (LB10) were selected. Cross-sectional images of the bronchi were extracted to measure the long diameter (Din-L), short diameter (Din-S), inner lumen area (ILA), and wall area (WA).

Results: Din-L, ILA, and WA were larger in the inspiratory phase for RB1, RB5, LB(1+2), and LB10. RB10 and LB5 showed larger Din-L, Din-S, ILA, and WA at the inspiratory phase. Significant differences were found in Din-S for LB5 and RB5. Din-L showed significant differences across both phases for all bronchial segments.

Conclusion: Low-dose MSCT combined with FUJIFILM Corporation SYNAPSE 3D software offers a reliable, novel method for quantitatively studying segmental bronchial changes during different respiratory phases. This approach uniquely captures dynamic bronchial behavior across both inspiratory and expiratory phases in healthy individuals, providing new insights into airway structure. However, further validation through phantom or cohort studies is needed to assess measurement accuracy.

Clinical trial number: Not applicable.