Observation of Gravitational Dependence of Regional Fractional Ventilation in Human Lungs with 2D and 3D Multi-Breath Washout Imaging of 3He and 129Xe

Felix Clemens Horn¹, Martin Heiner Deppe¹, Helen Marshall¹, Graham Norquay¹, Juan Parra-Robles¹, Jim Wild¹

The effects of gravity in multiple-breath inert gas washout MRI of hyperpolarised ³He and ¹²⁹Xe with 2D and 3D imaging are demonstrated in a volunteer at 1.5 T. To compare different washout experiments the regional fractional ventilation factor r (=% of gas exchanged per breath) was used. It is seen that the gravitational effects are irrespective of imaging sequence and gas type being used and the offset between r-values of different experiments is likely to be dependent upon the gas used, on sequence and respirational volume.