TY - JOUR T1 - Regional ventilation quantified by multi-volume computed tomography (CT): Comparison with 3-helium magnetic resonance imaging (<sup>3</sup>He-MRI) JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P538 AU - Francesca Pennati AU - Caterina Salito AU - James Quirk AU - Mario Castro AU - Jason Woods AU - Andrea Aliverti Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P538.abstract N2 - Maps of Specific Gas Volume variations (ΔSVg) between different lung volumes have been proposed to identify and quantify the extent and severity of trapped gas in severe emphysema (Aliverti et al, ERJ 2013). The aim of this study was to compare ΔSVg maps to the corresponding 3He ventilation images.Five asthmatic subjects were scanned at total lung capacity (TLC) and residual volume (RV) through high-resolution CT. Images at TLC were registered onto the RV scans (Thirion, MedImageAnal 1998),and maps of ΔSVg were obtained by subtracting voxel-by-voxel the two lung volumes. On the same subjects, 3He ventilation imaging was performed at FRC+1L. ΔSVg and 3He data were compared per patient by computing the linear correlation between the median values of ΔSVg and 3He in thirty corresponding regions, selected in ventral, intermediate and dorsal areas at five equally-spaced lung levels between aortic arch (AA) and top diaphragm (TD).Fig. 1 shows ΔSVg maps (top), the corresponding 3He-MR images (middle) and their correlation (bottom, R2=0.56, p&lt;0.001) in a representative patient with ventilation defects in the upper lobes. In the overall population the average±SD correlation coefficient was R2=0.54±0.09 (p&lt;0.001).In conclusion, CT-based and 3He-MRI ventilation imaging show a reasonable correlation in asthmatic subjects, suggesting that ΔSVg maps can be used to identify ventilation defects. ER -