We compared computed tomographic pictures (CT) of primary pulmonary mycobacterium avium complex (MAC) infection with bronchiectasia (BE). These patients were examined during the period from 1988 to 1996. There were 51 patients of pulmonary MAC infection group (13 males and 38 females) with a mean age of 67.5 years and 27 patients of BE group (8 males and 19 females) with a mean age of 53.9 years. The results were as follows:
1. In both groups, bronchiectasis was most commonly found in the middle lobe and in the lingula. In pulmonary MAC infection group, 38 patients (74.5%) had bronchiectasis in the middle lobe, and 40 patients (78.4%) had them in the lingula. In BE group, 18 patients (66.7%) had them in the middle lobe and in the lingula respectively. In the lower lobe, bronchiectasis of BE group was observed more frequently. And in pulmonary MAC infection group, 15 patients (29.4%) had bronchiectasis in the central zone, 42 patients (82.4%) had them in the intermediate zone, and all 51 patients had them in the peripheral zone. On the other hand, in BE group, 18 patients (66.7%), 27 patients (100%) and 21 patients (77.8%) had them in the central zone, in the intermediate zone and in the peripheral zone respectively. Bronchiectasis of pulmonary MAC infection was observed in peripheral zone more frequently than that of BE group.
2. By the type of bronchiectasis, saccular bronchiectasis was observed more frequently in BE group than in pulmonary MAC infection group.
3. Nodules were seen in pulmonary MAC infection group significantly more than in BE group. They were seen in 96% of lobes with bronchiectasis, and 50% of lobes without bronchiectasis in pulmonary MAC infection group.
It was thought that the bronchiectasis with nodules predominantly in the peripheral zone was a characteristic CT finding of primary pulmonary MAC infection. As this finding was different from that of BE, it is suggested that primary pulmonary MAC infection caused this type of bronchiectasis.
