Assessment of airway caliber in quantitative videobronchoscopy

Abstract

Background: Quantitative assessment of airway caliber is generally confined to indirect methods. Fiberoptic bronchoscopy provides a direct view of the airways, but measurement of the internal size of bronchi in a standard examination is not possible. Using a special image analysis program, we developed a method allowing quantitative assessment of airway caliber by means of videobronchoscopic (VB) examination.

Objectives: The purpose of the study was toshow that quantitative videobronchoscopy (VB coupled with a computer image analysis) allows direct and accurate measurement of the bronchi diameter.

Methods: To test our hypothesis, we measured the same areas of a bronchial tree in CT and in VB in 40 patients with diagnostic indications for both the procedures.

Results: We measured the diameters of 149 bronchi. The mean value of the difference between VB and CT measurements was equal to -0.071 mm and was not significantly different from 0 (p = 0.086). There was no obvious relation between the difference and the mean (r = 0.026, p = 0.745). The Bland Altman limits of agreement were L = -1.071 mm and U = 0.929 mm. We also assessed the bronchial diameter after endobronchial challenge and in patients with tracheobronchomalacia to show the application of this method for dynamic measurements.

Conclusions: Quantitative videobronchoscopy allows the accurate and direct measurement of an airway caliber. It may be useful in clinical setting to quantify changes in a bronchial caliber (endobronchial masses, tracheobronchomalacia). Dynamic visualization of changes in airways may be useful in research, especially to explore the mechanics of airway narrowing.