LAUSR

Introduction: FRI can provide a detailed view of regional lung structure and function thereby capturing disease heterogeneity in IPF. Aims and objectives: To investigate the correlation between lung function and FRI parameters of lung and airway volumes. Methods: In this single arm study 66 IPF patients (67.9±7.0 years) completed 48 weeks of treatment with an anti-CTGF monoclonal antibody. Pulmonary function was assessed every 12 weeks and HRCT scans (TLC and RV) and were taken at baseline, 24w and after 48w. Mixed effects models were used to investigate the correlation between lobe and airway volumes and FVC. Results: Reduced FVC was significantly associated with reduced upper (R 2 =0.5, p 2 =0.33, p 2 =0.31, p 2 =0.28, p<0.001) lobes (Figure 1). Interestingly, the lower lobes already show advanced disease (50-60%p) for normal FVC. The relative increase in airway calibre is likely due to a combination of traction fibrosis and redistribution of intrapulmonary pressure. Figure 1: Change in lobar volume (top) and specific airway radius (bottom) as a function of FVC Conclusion: Heterogeneous nature of IPF is poorly reflected in conventional endpoints. FRI can capture clinically relevant disease progression through regional assessment of lung structure and function.