Multisite implementation of 129Xe-MRI assessment of COPD disease progression: XeCITE early results

Abstract

Background: Sensitive markers of COPD progression are needed. Xe-MRI ventilation defect % (VDP) and gas-exchange metrics (membrane/gas (MDP), red-blood-cells/gas (RDP)) may be more sensitive to early progression than current clinical endpoints. Objectives: 1) Validate a harmonized Xe-MRI protocol in multicenter setting, and 2) Evaluate suitability of Xe-MRI metrics as measures of progression and predictors of acute exacerbations (AEx). Methods: Effectiveness of a Xe-MRI protocol for Siemens and GE MRI systems [1] was tested in healthy volunteers (HV) at 7 sites with a standardized quality check via a reproducibility assessment. Patient cohorts (n = 11 ongoing) included GOLD II-IV with history of AEx treated with SOC ± azithromycin, and GOLD I. Xe-MRI and PFTs were done at 0, 6, 12, 24, and 48 weeks. Quantitative CT exams at 0, 24 and 48 weeks for volume %normal, %emphysema, and %gas-trapping [2]. Results: In HVs homogeneous gas exchange and repeatability was observed (n = 5, r=0.98, p<.001). In COPD patients, baseline VDP correlated with FEV1 (-0.78, p<.05) and %normal CT (-0.72, p<.05). MDP correlated with %emphysema (0.81, p<.05). A GOLD III patient who experienced AExs and COVID during the 48 weeks showed an increase in MDP & RDP, and decrease in FEV1 (Fig1). Conclusions: A harmonized multicenter Xe-MRI protocol was successful. Early results in COPD patients show correlations between Xe-MRI, HRCT, and PFT.