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Conference Abstract: Hyperpolarised 129Xe diffusion-weighted MRI in ILD

Hyperpolarised 129-xenon diffusion-weighted MRI in interstitial lung disease (Conference Abstract)

James Eaden, Ho-Fung Chan, Paul Hughes, Nicholas Weatherly, Matthew Austin, Laurie Smith, Jim Lithgow, Andrew Swift, Stephen Renshaw, Maya Buch, Colm Leonard, Sarah Skeoch, Nazia Chaudhuri, Geoff Parker, Stephen Bianchi, Jim Wild

European Respiratory Journal 2019 54: PA3157. doi: 10.1183/13993003.congress-2019.PA3157.


Introduction: Apparent diffusion coefficient (ADC) is a measure of gas diffusion in the airspaces, where restrictions by tissue boundaries provide information about lung microstructure down to the alveolar level. Diffusion-weighted (DW) MRI of the lung with hyperpolarised helium in idiopathic pulmonary fibrosis (IPF) has shown that ADC correlates with DLCO, KCO and CT fibrosis score (Chan, H-F. et al. Radiology 2019; doi:10.1148/radiol.2019181714) but to date no data are available on the utility of 129-xenon (129Xe) diffusion in interstitial lung disease (ILD). Aim: To evaluate the ability of 129Xe DW-MRI to distinguish between ILD subtypes.

Methods: A prospective, multicentre study of patients with ILD including drug induced ILD (DI-ILD), hypersensitivity pneumonitis (HP), IPF and connective tissue disease ILD (CTD-ILD). Hyperpolarised 129Xe DW-MRI was performed on a 1.5 T scanner and mean ADC was calculated. Results: To date, 33 patients (6 DI-ILD, 7 HP, 15 IPF, 5 CTD-ILD) have undergone baseline 129Xe DW-MRI. There was a significant difference in mean ADC between the ILD subtypes (p=0.011), with the significant difference occuring between the HP (median: 0.038cm2/s) and IPF (median: 0.048cm2/s) groups (p<0.01). Median FVC% predicted in the HP and IPF groups was 75.6% and 84.7% respectively. There was a correlation between mean ADC and DLCO (r=-0.39; p=0.03) as well as KCO (r=-0.58; p<0.01) but not FVC (r=0.24; p=0.19).

Conclusions: We demonstrate a correlation between mean 129Xe ADC and DLCO but not FVC. Our findings suggest significant differences in mean ADC between IPF and HP. Therefore, 129Xe DW-MRI could potentially have a role in differentiating changes in the airway microstructure in ILD subtypes.