All the patients will have endobronchial valves insertion. We will evaluate before and 3 months after the evolution of the diaphragmatic strength and conformation.

a prospective monocentric study on hyperinflated COPD patients without collateral ventilation. Patients were evaluated before and 3 months after unilateral ELVR by transdiaphragmatic pressure (Pdi) measured at the functional residual capacity (FRC) after magnetic phrenic stimulation and by high-resolution computed tomography at the FRC allowing 3D modelling of the diaphragm for measurements of fibers length, length of the zone of apposition and radius of curvature of the diaphragmatic domes.

evaluate the difference in diaphragmatic function, assessed by the transdiaphragmatic pressure, before and 3 months after unilateral valves setting

evaluate the change of the diaphragm conformation, by measuring diaphragmatic fibers length in several planes, diaphragmatic area and radius of curvature, before and 3 months after unilateral ELVR.