TY - JOUR T1 - Visualising regional ventilation heterogeneity by linking multiple breath washout to <sup>3</sup>He MRI imaging JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P546 AU - Felix Horn AU - Alex Horsley AU - Laurie Smith AU - Christopher Tayler AU - Helen Marshall AU - Juan Parra-Robles AU - Jim Wild Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P546.abstract N2 - Introduction: Fractional ventilation imaging with 3He MRI can be used to visualise the processes underlying inert gas multiple breath washout measurement (MBW) from a regional perspective [1].Objectives: This proof-of-principle study compares MBW-imaging to clinical MBW measurements.Methods: Both methods were performed in 5 healthy volunteers (22±10years; 3 females) and 7 patients with mild-CF (age 12.7±2.6years, 2 males, FEV1&gt;80%)1) 0.2% SF6 MBW was performed supine to mimic posture in MRI.2) MBW-imaging was performed with sequential 3He MRI [1]. Washout time-constants were calculated for each individual voxel (∼1cm3) and integrated to produce a predicted washout curve from the whole lungs.The total normalized tracer gas volume expired at each breath was plotted for both SF6 and 3He against lung turn over.Results: There was good agreement between methods (see Figure ).Spatial heterogeneity of ventilation was observed in both curves for this CF patient with a deviation from mono exponential decay, and was clearly seen in the MBW fractional ventilation images.Conclusions: This preliminary study shows that simulated washout from imaging predicts that from MBW. MBW-imaging gives novel spatial insight into washout time constants within the lung, and will play an important role in understanding ventilation heterogeneity in the context of MBW indices (e.g. LCI).References:[1]Horn et al., JAP;[116]129-39. ER -