3D MR spirometry in healthy volunteers at 1.5 T using a UTE sequence with a flexible k-space sampling pattern

Motivation: To study lung function using 3D MR spirometry. Goal(s): To optimize 3D dynamic lung MRI with flexible k-space sampling for UTE acquisition. Approach: A non-Cartesian UTE sequence is developed to execute arbitrary trajectories stored in a readily available external gradient file library. 3D MR spirometry was then performed on freely-breathing healthy volunteers at 1.5 T. Results: High-quality 4D lung images are obtained, enabling the extraction of relevant respiratory biomarkers. Image quality can then be optimized by directly playing back the shapes and durations of the readout gradients from the files. Impact: A non-Cartesian, center-out MR sequence that allows out-of-the-box UTE capabilities with flexible k-space trajectories is developed. The result is high-quality 4D lung imaging in free-breathing and supine conditions. The lung functional biomarkers are expected to be sensitive to pathology.