We will build the instruments and design the methodologies to perform 3D MR spirometry acquisitions in V|LF systems (0.1 T, 0.2 T and 0.55 T). New RF coils, new pulse sequences, and new reconstruction algorithms will be developed for every strength. The technique will be validated on patients and healthy adults and children at low field (0.55 T). The imaging performances will also be proven in healthy adults at very-low field (below 0.1 T).