Tapering Analysis of Airways with Bronchiectasis

TL;DR

This paper introduces a new method for diagnosing bronchiectasis by measuring airway tapering in CT scans, providing a potentially more accurate alternative to traditional broncho-arterial ratio analysis.

Contribution

The study develops a pipeline to quantify airway tapering in CT images, demonstrating its effectiveness in distinguishing bronchiectatic airways from normal ones with high precision.

Findings

Significant difference in tapering rates between bronchiectatic and normal airways

Method achieves sub-voxel accuracy in measuring airway dimensions

Robust to airway bifurcations and validated with phantom models

Abstract

Bronchiectasis is the permanent dilation of airways. Patients with the disease can suffer recurrent exacerbations, reducing their quality of life. The gold standard to diagnose and monitor bronchiectasis is accomplished by inspection of chest computed tomography (CT) scans. A clinician examines the broncho-arterial ratio to determine if an airway is brochiectatic. The visual analysis assumes the blood vessel diameter remains constant, although this assumption is disputed in the literature. We propose a simple measurement of tapering along the airways to diagnose and monitor bronchiectasis. To this end, we constructed a pipeline to measure the cross-sectional area along the airways at contiguous intervals, starting from the carina to the most distal point observable. Using a phantom with calibrated 3D printed structures, the precision and accuracy of our algorithm extends to the sub voxel level. The tapering measurement is robust to bifurcations along the airway and was applied to chest CT images acquired in clinical practice. The result is a statistical difference in tapering rate between airways with bronchiectasis and controls. Our code is available at https://github.com/quan14/AirwayTaperingInCT.