Purpose: TM is an excessive narrowing of the intrathoracic part of the trachea. TM is a common congenital pediatric anomaly, but it’s often not recognized due to its unspecific clinical presentation. The aims of our study are: 1) to develop cine-MRI sequences to visualize central airways in static and dynamic conditions in patients that were able to follow specific breathing manoeuvres;2) to develop post-processing tools for image analysis.

Methods and Materials: To date 10 subjects (7 males; 2 adults) were enrolled in the pilot study: mean age 15, (range 6 to 30yrs). Volunteers were trained to perform spirometry controlled breathing maneuvers (peak flow and coughing) using a MRI compatible spirometer. “Static” 13-second breath-hold scans covering the entire thoracic region were acquired at end-inspiration and end-expiration using a 3D GRE with TR/TE=1.2/0.5 ms, alpha = 2, sagittal isotropic volume (2.8) x 3mm3 voxels. “Dynamic” scans were performed with the same parameters but covering only the central thorax (1/3 volume), temporal resolution was 500 ms per volume using the TRICKS. In-house developed software for segmentation and analysis was used.

Results: All subjects managed to follow the required breathing maneuvers. Images of central airways during static and dynamic conditions were acquired and could be analyzed. Three out of the 8 children had a TM just above the carina during forced expiration, confirmed by bronchoscopy.

Conclusion: This pilot study shows that Dynamic-MRI is feasible in pediatric population and allows avoiding radiation exposure and bronchoscopy for the evaluation of central airway dimensions.