Assessment of airway caliber in quantitative videobronchoscopy

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.

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.

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.

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.

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.