To assess mucociliary clearance in patients with tracheobronchoplasty, radioaerosol inhalation scanning was performed in 14 patients. The unilateral total lung clearance curve was fitted into two compartmental curves, fast and slow, by least-squares techniques in order to assess mucociliary clearance of the bronchial tree quantitatively. Half-time (T 1/2) of the curve resulting from the subtraction of the slow compartment curve from the fast compartment curve was calculated. The mucociliary clearance of the bronchial tree post so-called lobectomy (N = 5) was intact (T 1/2; 13.1 +/- 7.3 min). On the other hand, the mucociliary clearance of the bronchial tree postreconstruction (N = 14) was prolonged (T 1/2; 28.3 +/- 10.6 min), compared with that of the control bronchial tree (N = 15, T 1/2; 11.9 +/- 3.9 min) (p less than 0.01). However, the mucociliary clearance of the bronchial tree postreconstruction showed improvement with the passage of time, and the original clearance was regained 5 to 12 mo after the operation. Radioaerosol inhalation studies revealed both the degree of impairment and the recovery time of mucociliary clearance in patients post-tracheobronchoplasty.