X-ray velocimetry provides temporally and spatially-resolved biomarkers of lung ventilation in small airways disease.

BACKGROUND

Small airways disease is a feature of many respiratory conditions. Currently available methods of diagnosing small airways lack sensitivity and/or cannot evaluate spatial heterogeneity. New diagnostic strategies for diagnosing small airways disease are needed.

METHODS

We determined the regional displacement of lung tissue calculated from fluoroscopic lung images acquired at multiple angles over sequential time points as a surrogate of ventilation. We applied this technique, which we call X-ray velocimetry (XV), to patients with chronic obstructive pulmonary disease (COPD) and impaired spirometry and veterans with deployment-related constrictive bronchiolitis (DR-CB) but preserved spirometry to determine XV-derived biomarkers specific for each condition.

RESULTS

We identified disease- and stage-specific XV biomarkers for COPD patients that correlated with airflow obstruction on spirometry. Further, we identified a set of XV-derived biomarkers that could distinguish veterans with DR-CB from controls despite normal spirometry in most patients from both groups.

CONCLUSIONS

XV may provide a safe and widely-available strategy for diagnosing small airways disease while preserving spatial information. Future studies are required to validate the biomarkers described here in larger patient cohorts.

TRIAL REGISTRATION

Not required for this study. However, participants enrolled at VUMC were enrolled under ClinicalTrials.gov study NCT04489758 (submitted 07/23/2020).