Pierluigi Ciet, Presenter: Nothing to Disclose

Piotr Alfred Wielopolski PhD, Abstract Co-Author: Nothing to Disclose

Sandra Lever, Abstract Co-Author: Nothing to Disclose

Marleen de Bruijne PhD, Abstract Co-Author: Nothing to Disclose

Maarten H. Lequin MD, PhD, Abstract Co-Author: Nothing to Disclose

Harm Awm Tiddens MD, Abstract Co-Author: Nothing to Disclose

Tracheomalacia(TM) is an exaggerated collapse of the intrathoracic part of the trachea. Bronchoscopy is the gold standard method for diagnosis, but requires general anaesthesia and therefore does not supply information during standardized breathing manoeuvres and it is cumbersome to acquire exact airway dimensions. Cine-CT can be used as a non-invasive alternative to diagnose TM; it does not require anaesthesia and airways can be studied during static and dynamic conditions, which are highly relevant for the diagnosis of TM. An important drawback of cine-CT in children is the radiation burden. The aim of our study is to develop cine-MRI sequences to visualize central airways in static and dynamic conditions and to develop post-processing tools for automated image analysis.

To date cine-MRI has been used in 4 adult volunteers and in 6 children (mean age 14) with a suspicion for TM, evaluated also by bronchoscopy. Subjects were trained to perform breathing manoeuvres (forced expiration and coughing) prior to the MRI to optimize the imaging assessment. Cine-MRI settings: BH scans (13”) covering the entire thoracic region were acquired at end-inspiration and –expiration using a 3D gradient echo (GRE) sequence (TR/TE=1.2/0.5ms, α=2°, sagittal acquisition, isotropic 2.8mm3voxels). 3D Dynamic-scans were performed with the same parameters, but covering only the central thorax region (1/3 volume, temporal resolution=500ms/volume) using TRICKS sequence. In-house software for segmentation and analysis was used.

All subjects managed to follow the required breathing manoeuvres. Images of central airways during static and dynamic conditions were acquired and could be analyzed. One of the 6 children had a TM just above the carina during forced expiration, confirmed by bronchoscopy.

This pilot study shows that Cine–MRI can be used as a non-invasive radiation free alternative for bronchoscopy to acquire static and dynamic images of the central airways of sufficient quality to allow analysis of central airway dimensions.

This work is highly relevant for clinical research and practice: automated lumen segmentation in patients with TM is the first step for automatic grading of airway malignancy.

Ciet, P, Wielopolski, P, Lever, S, de Bruijne, M, Lequin, M, Tiddens, H, Tracheomalacia Assessment in Pediatric Patients with MR Imaging: Preliminary Report.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9015254.html