Oxygen-enhanced MRI versus PREFUL in assessing pulmonary ventilation in COPD and healthy individuals.

<bold>Aim:</bold> To assess pulmonary ventilation using T₂*-OE-MRI (oxygen-enhanced MRI) vs. free-breathing phase-resolved functional lung (PREFUL)-MRI in COPD and healthy volunteers (HVs). <bold>Methods:</bold> 13 COPD patients and 13 age-matched HVs underwent PFTs, and two lung MRI at 3T. For T₂*-OE-MRI, 21% oxygen was delivered at 15l/min using a non-rebreathing face mask, then switched to 100% oxygen during image acquisition. PREFUL protocol consisted of 6-single-slice dynamic gradient echo sequences with slice positions matched to T₂*-OE-MRI slice sequence. Slice 5 is used here as a representative. <bold>Results:</bold> Patients were heavy smokers (FEV₁: 59.7±24.4 %predicted (mean±SD)). During T₂*-OE-MRI, the percentage difference between mean signal intensity at normoxia and hyperoxia (PSE) and the enhancing fraction (EF) were lower in COPD vs. HVs (both p<0.01). The total ventilation defect percentage (VDP) during PREFUL was 36±14 vs. 21±14% in patients vs. HVs (p=0.01). Bland-Altman analyses and intra-class correlation coefficient indicated moderate-good repeatability of PSE, EF, and VDP, but VDP looks less discriminating between HVs and COPD (Fig). Total VDP correlated with PSE (r=-0.49,p=0.01) and EF (r=-0.62,p=0.001). Across all slices, PSE, EF, and VDP correlated well with FEV₁ and lung clearance index. <bold>Conclusion:</bold> Like PREFUL, T₂*-OE-MRI provides useful, repeatable information on pulmonary ventilation distribution in patients with COPD. <fig><object-id>erj;64/suppl_68/PA3385/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>