LAUSR

Introduction: Novel biomarkers are needed to improve assessment of ILD. Oxygen enhanced MRI (OE-MRI) monitors regional O2 delivery from changes in the MRI relaxation time T1 in response to hyperoxia. We present OE-MRI biomarkers in different ILD phenotypes (IPF, DI-ILD, CTD-ILD, HSP) acquired in a prospective observational study and compare them with lung function tests under standard clinical care. Methods: Patients recruited and scans analysed to date are summarised in fig 1. The OE MR parameters considered were: baseline T1, change in delta pO2 (ΔpO2), O2 wash-in time and ventilated volume fraction. Biomarker values at each visit and the change between visits were compared with lung function tests (FVC%, FEV1%, Tlco%, KCO%) using Pearson correlation (no correction for multiple comparisons). Results: In the IPF subgroup, T1 correlated with Tlco% and KCO% (r=-0.43, p=0.027 and r=-0.43, p=0.028). Changes between visits in ΔpO2 and in KCO%(r = 0.86, p=0.003) were also correlated. No significant correlations were found in other phenotypes. Conclusions: In IPF, change between visits in ΔpO2 correlates with the change in KCO%, but not in the other ILD subtypes.