Tracheobronchial stenosis evaluated by inspiratory and expiratory three-dimensional computed tomography and impulse oscillation with three-dimensional color imaging in a patient with relapsing polychondritis.

Patients with relapsing polychondritis (RP) and airway stenosis have difficulty performing conventional spirometry that requires maximum forced expiration. We report a patient with RP who showed progressive severe bronchial stenosis on three-dimensional computed tomography (3D-CT) and impulse oscillation (IOS) with 3D color imaging using a Mostgraph®. The forced oscillation technique using IOS allows within-breath evaluation without forced expiration. A 68-year-old man who had RP presented with dyspnea due to stenosis of the trachea and left main bronchus (lt. mb). Stenting was performed twice in two years. Chest 3D-CT revealed a marked difference in the extent of bronchial collapse during expiration compared with inspiration. The forced expiratory volume in 1 second (FEV1.0), reactance at 5Hz (X5), resonant frequency (Fres), and integrated low frequency reactance area (ALX) measured by IOS showed temporary improvement after placement of the first stent, but respiratory resistance at 5Hz (R5) and 20Hz (R20) remained poor. 3D color images of respiratory resistance obtained with a Mostgraph® already showed high values at the time of diagnosis, resembling the features of chronic obstructive disease (COPD). 3D color images were helpful for interpreting the changes of IOS parameters during the clinical course. In conclusion, 3D-CT in inspiration/expiration and noninvasive IOS with 3D color imaging are useful for assessing airway stenosis in RP while reducing the burden of repeated spirometry.