Introduction

Small airways dysfunction (SAD) is an increasingly recognized aspect of asthma pathophysiology. Quantitative computed tomography (qCT) imaging of the lungs may provide additional insight into SAD in addition to physiological measurements. However, the relationship between qCT biomarkers, small airway physiology and clinical patient reported outcomes (PROs) is still poorly understood.

Objectives

To determine whether a particular set of qCT imaging biomarkers are associated with physiological SAD markers and asthma PROs over 1 year.

Methods

Data from the Assessment of Small Airways Involvement in Asthma (ATLANTIS) study, including 47 healthy and 278 asthmatic participants, were used. qCT markers capturing lung tissue deformation gradients, imaging lung volume and mean lung density were extracted. Leading variables of five radiomic signatures derived from factor analysis were evaluated as predictors of physiological SAD (R5-R20, Sacin, RV/TLC, FEF25-75) and PROs (ACQ, AQLQ, SAD questionnaire score, EuroQoL-5D-5L and asthma exacerbations) using mixed models.

Results

The lung density gradient along the anterior-posterior axis was significantly associated with all four SAD markers of interest over the 1-year prospective follow-up, where reduced posterior ventilation suggests increased SAD. None of the qCT markers were significantly associated with clinically important changes in the PROs of interest.

Conclusions

The selected qCT imaging biomarkers were associated with prospective SAD. The results underscore qCT as a potential screening tool for early, pre-symptomatic asthma. However, this would need to be tested in prospective studies.