Tracheal diverticula in cystic fibrosis-A potentially important underreported finding on chest CT.

Background: We aim to assess the prevalence and describe characteristics of tracheal diverticula (TD) in patients with cystic fibrosis (CF).

Methods: This retrospective study included 92 patients with known CF treated in our medical center who had available chest CT, performed between 2001 and 2013. Presence, number, size, and location of TD were recorded on the most recent chest CT. The severity of CF-related pulmonary CT findings and pulmonary function tests were recorded and correlated with the presence of the diverticula.

Results: Twenty-six (28%) of the 92 patients (17 males, 9 females, age range 5-59years) had one or more TD. The size of TD ranged from 2mm to 32mm. TDs were on the right posterolateral aspect of the upper tracheain nearly all patients. Small TDs appeared as a focal paratracheal lucency and larger ones as a soft tissue mass with central air bubbles. There was no significant difference in the Bhalla score between patients with and without TD. There was no correlation between the Bhalla score and patients' age, size, or number of diverticula. Pulmonary function tests were worse and declined faster in patients with TD compared to those without.

Conclusions: TDs are quite common on chest CT of CF patients. Those with diverticula have significantly worse pulmonary function tests than those without.