Tracheomalacia by computed tomography (CT)

Axial CT airway imaging in (A) inspiration and (B) expiration and (C) dynamic expiration. There is excessive tracheal collapsibility on expiration. Note that in some cases the collapse cannot be demonstrated on end-exhalation, but is much more prominent on dynamic imaging. Reliance on in- and expiratory imaging alone can be a source for false negative examinations.