Large airway diseases in pediatrics: a pictorial essay

Abstract

"Large airway diseases" is being used as an all-encompassing phrase to describe a broad spectrum of pathological entities, which involves the trachea, main, lobar, and segmental bronchi of up to 3 mm diameter. Imaging modalities such as radiography, computed tomography, and magnetic resonance imaging contribute to the identification and diagnosis of each entity. Knowledge of clinical information, normal cross-sectional anatomy, and imaging characteristics of large airway diseases is necessary for appropriate radiologic evaluation. This review provides information about congenital and acquired diseases of the large airways in the pediatric population.

Keywords: CT; Chest; airways; bronchi; pediatric; trachea.

Fig. 1.

Coronal MPR showing a 17-year-old boy with right displaced tracheal bronchus (TB) for the posterior and apical segments and a normal bronchus (NB) for the RUL supplying the anterior segment, arising from the right main bronchus. The patient also exhibits noted scoliosis due to his underlying condition of arthrogryposis. CTDI_vol = 4.5 mGy.

Fig. 2.

(a) Axial CT image of a 5-year-old boy with left lung aplasia showing the hyperinflated right pulmonary parenchyma and the rudimentary left main bronchus (black arrow). (b and c) 3D volume-rendering technique (VRT) shows the rudimentary left main bronchus (white arrow). CTDI_vol = 1.1 mGy.

Fig. 3.

Bronchial atresia as an incidental finding in a 16-year-old male. (a) Axial minimum intensity projection CT image depicting the atretic right anterior segmental bronchus dilated and filled with mucus (arrow), surrounded by hypo-attenuated lung parenchyma due to air-trapping. (b) Sagittal CT image showing the characteristic Y-shaped atretic anterior segmental bronchus filled with mucous (arrow). CTDI_vol = 4.3 mGy (combined chest–abdomen–pelvis examination).

Fig. 4.

(a) Coronal minimum intensity projection and (b) 3D volume-rendering technique on a 7-month-old boy with mild congenital stenosis of the distal trachea and more prominent of the left main bronchus (arrows). Mosaic appearance of lung parenchyma due to air trapping can be appreciated. Tracheal stenosis was confirmed by flexible bronchoscopy. CTDI_vol = 1.88 mGy.

Fig. 5.

Bronchogenic cyst in a 10-year-old boy. MRI scan shows a thin-walled cystic lesion (arrow) with protein content in contact with the anteriorly displaced right main bronchus on (a) axial T2WI, (b) axial T1WI FatSat, and (c) axial BTFE studies, which do not show contrast enhancement on (d) T1WI FatSat post-gadolinium injection.

Fig. 6.

Esophagogram of a 20-day-old male revealing a congenital tracheoesophageal fistula (arrow). DLP = not available.

Fig. 7.

Chest CT on an 8-year-old boy shows the communication (arrow) between the trachea and the esophagus, and the formation of an acquired tracheoesophageal fistula. CTDI_vol = 2.2 mGy.

Fig. 8.

Chest MR angiography showcasing a double aortic arch on a 4-month-old male surrounding and compressing the trachea. (a and b) Axial T1WI post-gadolinium injection MR angiography and (c) coronal maximum-intensity projection.

Fig. 9.

Acquired tracheomalacia. Paired end-inspiratory/forced-expiratory CT. (a and b) End-inspiration phase and (c and d) forced-expiration phase show significant expiratory reduction in the cross-sectional luminal area of the trachea (arrow). Mosaic appearance of the apical lung parenchyma due to air trapping can be appreciated. CTDI_vol = 2.47 mGy (inspiration) and 2.41 mGy (expiration).

Fig. 10.

Foreign body aspiration (crushed nuts) in a 3-year-old boy on (a) chest radiography. (b and c) CT images showing multiple opacities inside the tracheobronchial tree (arrows) with peripheral lung collapse. (d) Bronchoscopic image showing part of nut swallowed. CTDI_vol = 0.83 mGy.

Fig. 11.

Incidental finding of papillomatous lesions on the tracheal wall. (a and b) Coronal and (c) sagittal CT image showing multiple nodular lesions (black arrows) projecting into the tracheal lumen. (d) Virtual bronchoscopy showcasing one of the papillomatous lesion (white arrow). CTDI_vol = 1.9 mGy (inspiration) and 0.52 mGy (expiration).

Fig. 12.

Neuroblastoma on a 9-year-old boy. (a and b) Axial CT image shows noted anterior displacement of the posterior mediastinal compartment and compression of the left main bronchus (arrow) due to mass effect from soft tissue mass, which encases the descending aorta. CTDI_vol = 3.6 mGy (combined chest–abdomen–pelvis study).

Fig. 13.

Mediastinal lymphadenopathy in a 9-month-old girl due to tuberculosis infection. (a and b) Axial CT images post-IV-contrast injection show lymph node conglomerates with necrosis and calcifications (white arrows) and (c) mild compression of the right intermediate bronchus (black arrow). CTDI_vol = 1.52 mGy.

Fig. 14.

Mediastinal lymphadenopathy on a 3-year-old girl due to Mycobacterium avium complex (MAC) infection. Oblique axial CT image shows a tumorous lesion (black arrow) obstructing the beginning of the medial segmental bronchus, along with the consolidation of the peripheral lung parenchyma and air bronchogram sign (arrowheads), which ultimately histologically proved to be, after middle lobe excision, lymphadenopathy from MAC infection. CTDI_vol = 2.7 mGy.