MRI of the upper airways in children and young adults: the MUSIC study

Abstract

RationalePaediatric laryngotracheal stenosis (LTS) is often successfully corrected with open airway surgery. However, respiratory and vocal sequelae frequently remain. Clinical care and surgical interventions could be improved with better understanding of these sequelae.ObjectiveThe objective of this cross-sectional study was to develop an upper airway MRI protocol to obtain information on anatomical and functional sequelae post-LTS repair.MethodsForty-eight patients (age 14.4 (range 7.5–30.7) years) and 11 healthy volunteers (15.9 (8.2–28.8) years) were included. Spirometry and static and dynamic upper airway MRI (3.0 T, 30 min protocol) were conducted. Analysis included assessment of postoperative anatomy and airway lumen measurements during static and dynamic (inspiration and phonation) acquisitions.Main resultsGood image quality without artefacts was achieved for static and dynamic images in the majority of MRIs. MRI showed vocal cord thickening in 80.9% of patients and compared with volunteers, a significant decrease in vocal cord lumen area (22.0 (IQR 17.7–30.3) mm2 vs 35.1 (21.2–54.7) mm2, p=0.03) but not cricoid lumen area (62.3±27.0 mm2 vs 66.2±34.8 mm2, p=0.70). Furthermore, 53.2% of patients had an A-frame deformation at site of previous tracheal cannula, showing lumen collapse during inspiration. Dynamic imaging showed incomplete vocal cord abduction during inspiration in 42.6% and incomplete adduction during phonation in 61.7% of patients.ConclusionsStatic and dynamic MRI is an excellent modality to non-invasively image anatomy, tissue characteristics and vocal cord dynamics of the upper airways. MRI-derived knowledge on postsurgical LTS sequelae might be used to improve surgery.

Structure and Function of the Vocal Cords after Airway Reconstruction on Magnetic Resonance Imaging

“…In summary, static imaging showed vocal cord thickening in the majority of patients (80.9%) 17 . In 12 patients (25.5%), signs of fibrosis located at the vocal cords were seen; in 6 patients (12.8%), signs of edema located at the vocal cords were seen; and in 9 patients (19.1%), a combination of fibrosis and edema was seen.…”

“…The study was approved by the local medical ethics committee (MEC2018‐013) and written informed consent was obtained from all study participants. Anatomical data were previously reported 17 …”

“…A 30‐min upper airways MRI protocol was developed and performed on a 3T scanner (Discovery MR750, GE Healthcare, Milwaukee, WI, USA) using a dedicated and flexible 6 channel carotid coil (Machnet B.V., Rhoden, The Netherlands and Flick Engineering B.V., Winterswijk, The Netherlands) 24 . The MRI protocol has previously been published 17 . Briefly, the protocol consisted of static two‐dimensional (2D) morphological sequences with high in‐plane resolution in three planes (0.5 × 0.5 (in plane) × 2 mm (slice thickness)) and 2D and 3D dynamic sequences with a temporal resolution of 330 ms.…”

“…Tissue characterization assessment consisted of the evaluation of T2‐weighted images on the presence of tissue thickening and/or hyperintense signal, as signs of fibrosis, edema, or a combination of both 17 …”

Practical protocol for lung magnetic resonance imaging and common clinical indications

“…T2-W sequences enable assessment of bronchial wall thickening and mucus plugging. Bronchial wall imaging can be further improved with black-blood preparations [ 10 , 11 ] using heavy T2 weighting (longer effective echo time). Black-blood preparation removes signal of pulmonary vessels, facilitating detection of bronchiectasis, mucus plugging and small nodules.…”