CT evaluation of airway foreign bodies in children: emphasis on the delayed diagnosis and differentiation from airway mucus plugs

Abstract

To review clinical and CT findings of airway foreign bodies (FBs) among children, with an emphasis on delayed diagnosis and differentiation from mucus plugs (MPs). The CT findings and medical records of 27 patients (M:F = 17:10; mean age, 18.2 months) confirmed for FB (n = 20) and MP (n = 7) were reviewed. These findings were correlated with the bronchoscopic results and clinical outcomes. CT revealed air-trapping (70 %), atelectasis (35 %), pneumonia (25 %), and pneumomediastinum (5 %). Three patients with FB in the carina did not show air-trapping. The densities of the FBs ranged from 17 to 123 Hounsfield units (HU) (n = 17). Eight out of 20 patients (33 %) had a delayed diagnosis of FB. The CT of eight patients revealed air-trapping (n = 2), air-trapping with pneumonia or atelectasis (n = 3), and atelectasis only (n = 1). The airway MPs had a low density (0-5 HU) and were associated with atelectasis (29 %), atelectasis with pneumonia (43 %), and pneumonia (14 %). Air-trapping of the ipsilateral lung may not be a reliable finding among patients with an FB located in the carina and with a small-calibered FB. The absence of air-trapping, the difference in the HU, and the shape of the endobronchial lesion are helpful findings in the differential diagnosis of an MP.