CT-guided radiolabelled aerosol studies for assessing pulmonary impairment in children with bronchiectasis

Objective. To determine whether CT-guided mucociliary clearance studies allow differentiation between bronchiectasis associated with primary ciliary dyskinesia (PCD) and those unrelated to congenital or genetically transmitted defects. Materials and methods. Fifteen children aged 4-18 years with a CT diagnosis of bronchiectasis were included in the study. Six had PCD, while in nine cases no congenital disorder was demonstrated. Results. CT showed bronchiectasis in 26 (29 %) of 90 lung regions. Radiolabelled aerosol studies were conducted globally for each lung and on the regions affected by bronchiectasis. Global half-time of activity (t(1/2)) values of patients with PCD were significantly higher (P < 0.001) than those with bronchiectasis unrelated to congenital disorders. Among the 26 lung regions in which CT demonstrated bronchiectasis, regional clearance was abnormal in 24 cases. Patients with PCD showed no statistically significant difference between regional and global t(1/2) values. Patients with bronchiectasis unrelated to congenital disorders showed significantly higher regional t(1/2) values in the affected regions with respect to the corresponding global pulmonary t(1/2) (P < 0.06). Conclusions. The combination of morphological CT information with functional data concerning the clearance of radiolabelled aerosol adds to our understanding of pulmonary impairment in children with bronchiectasis. In particular, regional studies allow the recognition of different mucociliary clearance patterns in bronchiectasis associated with PCD and those unrelated to congenital or genetically transmitted defects