PT - JOURNAL ARTICLE AU - Hallifax, RJ AU - Chen, M AU - Matin, TN AU - Rahman, NM AU - Gleeson, FV TI - S61 Novel assessment of ventilation abnormalities in primary spontaneous pneumothorax using Xenon-enhanced MRI AID - 10.1136/thorax-2018-212555.67 DP - 2018 Dec 01 TA - Thorax PG - A38--A38 VI - 73 IP - Suppl 4 4099 - http://thorax.bmj.com/content/73/Suppl_4/A38.1.short 4100 - http://thorax.bmj.com/content/73/Suppl_4/A38.1.full SO - Thorax2018 Dec 01; 73 AB - Background There is increasing evidence in patients with Primary Spontaneous Pneumothorax (PSP) of emphysema-like change (ELC) and inflammation. Pulmonary function tests are global metrics, not sensitive to subtle disease. Computed tomography scans can provide detailed structural, but not direct functional, information. Hyperpolarised 129Xenon magnetic resonance imaging (MRI) allows functional assessment of ventilation.Methods Patients underwent 129Xe MRI ventilation scan with a single breath-hold of 1L 129Xe with ˜10% hyperpolarisation. Percentage ventilation of lung receiving 129Xe hyperpolarized gas were analysed by lobe using a semi-automated software package.1 Results Of 10 PSP patients, 8 (80%) were male, (median age 28.6 years), 5 (50%) were current or ex-smokers. Mean overall%Ventilation was 88.0% (SD 4.8%) and was correlated with forced expiratory volume in 1 s, (R2 0.41, p 0.045) and diffusing capacity, (R2 0.77, p<0.001). Regional differences were demonstrated between lobes. Smokers had a reduced%Ventilation (overall 3.9%), which was particularly marked in the upper lobes: right 9.0%, left 4.8%.Conclusion This study demonstrates reduced% ventilation on 129Xe MRI in patients post-PSP. These areas may represent the ELC, known to be associated with PSP, and were more marked in smokers. 129Xe MRI is a non-ionising technique with the potential to visualise and characterise important subtle structural abnormalities. On-going work will assess pulmonary microstructure and gas transfer capacity to provide a comprehensive functional/structural evaluation on a regional basis, and its correlation with risk of PSP recurrence.ReferenceMatin, Radiology2017.