Quantifying Free-breathing Murine Tracheal Dynamics Using Retrospectively-Gated Ultra-short Echo-time (UTE) in MRI

The trachea expands and retracts almost uniformly while breathing, but these dynamics are altered by congenital malformation and injury to tracheal cartilage. Tracheal collapse—tracheomalacia—is a common comorbidity in of disorders, including bronchopulmonary dysplasia (BPD), idiopathic pulmonary fibrosis (IPF) and cystic fibrosis (CF) and can cause life-threatening airway obstruction. While tracheomalacia is clinically diagnosed via bronchoscopy, no tool exists to noninvasively assess tracheal dynamics in small animal models. Here we use retrospectively gated, 3D UTE to resolve changes in tracheal caliber during tidal breathing and show these dynamics change as a function of tracheal position and breathing rate.