Assessment of Central Airways Mechanics Using Dynamic Magnetic Resonance Imaging (Cine‐MRI): A Comparison to Flexible Bronchoscopy

Background Flexible bronchoscopy (FOB) is the current gold standard for diagnosing tracheobronchomalacia (TBM). While dynamic magnetic resonance imaging (cine‐MRI) has emerged as a radiation‐free alternative for TBM diagnosis, a direct comparison of its diagnostic performance with FOB has not yet been performed. Objective This study aimed to evaluate the diagnostic performance of cine‐MRI versus FOB in detecting TBM and to assess the effect of bronchodilators on observed tracheobronchial collapse. Methods The study included 10 children (median age 11 years, range 8–17 years; five males) who were referred for suspected TBM. Cine‐MRI was performed using a 3 Tesla GE 750 W scanner with specific sequences for static and dynamic imaging. Bronchodilator testing was conducted using 400 µg salbutamol. Children suspected of TBM underwent both FOB and cine‐MRI. Cine‐MRI protocol included spirometry‐controlled static and dynamic sequences, pre‐ and post‐bronchodilator administration. FOB diagnoses were made by pediatric pulmonologists, and cine‐MRI assessments were independently evaluated by two trained observers, blinded to FOB results. Moreover, each child completed spirometry and a respiratory questionnaire. Descriptive statistics were used to summarize data. Diagnostic agreement and measurements repeatability were assessed using the intra‐class correlation coefficient (ICC). Results FOB identified TBM in two children, whereas cine‐MRI detected TBM in four. In three of these four children TBM was not diagnosed by FOB. Notably, no TBM was observed during static pre‐bronchodilator cine‐MRI assessment, but two of the four children diagnosed with cine‐MRI met the diagnostic criteria of TBM only post‐bronchodilation. Conclusion Cine‐MRI, particularly post‐bronchodilation shows a unique capability to detect TBM cases undetected by FOB. This may reflect its ability to perform dynamic functional measurements during active respiratory maneuvers, highlighting its potential as a valuable diagnostic tool for central airway disease in children.