Respiratory Motion-Resolved 4D Pulmonary Imaging with Stack-of-Spiral UTE at 0.55T and 3T

Recently, ultrashort echo time (UTE) has gained renewed interest for lung imaging at 1.5T and 3T, which captures short T2* signal from lung parenchyma. Lower field is attractive for lung MRI due to prolonged T2* and reduced susceptibility, and it was demonstrated that high-resolution high-quality structural lung imaging can be achieved with UTE at 0.55T. In addition to anatomical information, pulmonary function such as regional ventilation is also of great clinical interest. In this study, we developed free-breathing respiratory-motion-resolved 4D pulmonary imaging using stack-of-spirals acquisition with compressed-sensing at both 0.55T and 3T, which could enable quantitative evaluation of ventilation dynamics.