Homogeneity of bronchopulmonary distribution of 99mTc aerosol in normal subjects and in cystic fibrosis patients.

We characterized the bronchopulmonary distribution of a 0.9 percent saline aerosol (1.12 microM) labelled with 99mTc sulfur colloid in nine normal subjects and five patients with CF. Homogeneity of distribution was quantified using indices derived from computerized analysis of Anger camera pulmonary images including skew (a measure of distribution asymmetry) and kurtosis (a measure of distribution range). Aerosol clearance in 97 minutes (a measure of large, central airway deposition) was also assessed. Values of skew and kurtosis were reproducible for the patients with CF and were significantly elevated compared to the normal subjects. Reproducibility of skew and kurtosis were not studied in the normal subjects. Clearance was not significantly different in the two groups. We conclude that the bronchopulmonary distribution of this radioaerosol is nonuniform in patients with CF, compared to normal subjects, and clearance may be impaired in patients with CF who are severely ill.