PT - JOURNAL ARTICLE AU - Laurie J. Smith AU - Alex Horsley AU - Jody Bray AU - Paul J. C. Hughes AU - Alberto Biancardi AU - Graham Norquay AU - Martin Wildman AU - Noreen West AU - Helen Marshall AU - Jim M. Wild TI - The assessment of short and long term changes in lung function in CF using <sup>129</sup>Xe MRI AID - 10.1183/13993003.00441-2020 DP - 2020 Jan 01 TA - European Respiratory Journal PG - 2000441 4099 - http://erj.ersjournals.com/content/early/2020/07/02/13993003.00441-2020.short 4100 - http://erj.ersjournals.com/content/early/2020/07/02/13993003.00441-2020.full AB - Introduction 129Xe ventilation MRI is sensitive to detect early CF lung disease and response to treatment. 129Xe-MRI could play a significant role in clinical trials and patient management. Here we present data on the repeatability of imaging measurements and their sensitivity to longitudinal change.Methods 29 children and adults with CF and a range of disease severity were assessed twice, a median [IQR] of 16.0 [14.4,19.5] months apart. Patients performed 129Xe-MRI, lung clearance index (LCI), body plethysmography and spirometry at both visits. Eleven patients repeated 129Xe-MRI in the same session to assess the within-visit repeatability. The ventilation defect percentage (VDP) was the primary metric calculated from 129Xe-MRI.Results At baseline, mean (sd) age=23.0 (11.1) years and FEV1 z-score=−2.2 (2.0). Median [IQR] VDP=9.5 [3.4,31.6]%, LCI=9.0 [7.7,13.7]. Within-visit and inter-visit repeatability of VDP was high. At 16 months there was no single trend of 129Xe-MRI disease progression. Visible 129Xe-MRI ventilation changes were common, which reflected changes in VDP. Based on the within-visit repeatability, a significant short-term change in VDP is &gt;±1.6%. For longer-term follow up, changes in VDP of up to ±7.7% can be expected, or ±4.1% for patients with normal FEV1. No patient had a significant change in FEV1, however 59% had change in VDP &gt;±1.6%. In patients with normal FEV1, there were significant changes in ventilation and in VDP.Conclusions 129Xe-MRI is a highly effective method for assessing longitudinal lung disease in patients with CF. VDP has great potential as a sensitive clinical outcome measure of lung function and endpoint for clinical trials.FootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Dr. Smith reports grants from National Institute for Health Research, during the conduct of the study.Conflict of interest: Dr. Horsley reports grants from National Institute of Health Research , during the conduct of the study; grants from Cystic Fibrosis Trust, grants from Cystic Fibrosis Foundation, personal fees from Mylan Pharmaceuticals, personal fees from Vertex Pharmaceuticals, outside the submitted work.Conflict of interest: Dr. Bray has nothing to disclose.Conflict of interest: Dr. Hughes reports grants from GlaxoSmithKline, outside the submitted work.Conflict of interest: Dr. Biancardi has nothing to disclose.Conflict of interest: Dr. Norquay has nothing to disclose.Conflict of interest: Dr. Wildman has nothing to disclose.Conflict of interest: Dr. West has nothing to disclose.Conflict of interest: Dr. Marshall has nothing to disclose.Conflict of interest: Dr. Wild has nothing to disclose.