1. Male to female ratio was 1:1.4, and peak incidence (64 %) was in the fifth and sixth decades with the mean age of 5 1. 1 years 2. Bronchiectasis was the most common cause (30.6 %), and the others were chronic bronchitis (25.0 %), pulmonary tuberculosis (1 9.4 %), lung cancer (16.7 %), and non-specific inflammatory disease (8.3 %). This suggests benign disease is 5 times more common cause of ritht middle lobe collapse than lung canCer 3. Among the plain chest radiolograph findings , obliteration of right cardiac border and triangular radiopaque density were the most frequent findings (77.8 % in each) and the next was downward and anterior displacement of minor and major fissures (55.6 %)4. Bronchography was done in 11 cases: bronchiectasis was found in 8 cases and chronic bronchitis in 3 cases. Right middle lobe bronchus was obstructed in 2 cases of chronic bronchitis 5. Chest C-T scan was performed in 4 cases of lung cancer, 2 of non-specific inflammatory disease , and 1 of pulmonary tuberculosis: all of lung cancer revealed hilar mass, buldged or lobulated fissures , inhomogenous density , and mediastinal lymphnode e nlargement, and all be nign diseases showed homogenous density and flat to concave fissures. Right middle lobar bronch us narrowing was seen in 5 cases and its obstruction in 2 cases• 충남대학교 의과대학 땅사션과

Open brochus w ith diffuse narrowing, stretching, and leafless t ree appearance of the bronchi is th e well