[A computed tomography-based study of features developmental patterns: Mycobacterium avium complex without predisposing conditions].

The aim of this study was to determine the computed tomographic (CT) features and developmental patterns of Mycobacterium avium complex disease (MAC disease). The author examined chest CT films from 36 cases of MAC without predisposing conditions, 8 early-stage cases, and 6 long-term follow-up cases. Prominent CT features included centrilobular abnormalities (in the lower part of the right upper lobe, middle lobe, and lingula predominance), airspace consolidation, and bronchiectasis in the middle lobe and lingula. Patterns of development typically began with centrilobular abnormalities in the lower part of the right upper lobe, middle lobe, or lingula. These centrilobular abnormalities tended to fuse, leading to airspace consolidation in the middle lobe and lingula. Bronchial wall thickening was followed by bronchiectasis in the middle lobe and lingula. These CT-image features and patterns (centrilobular abnormalities, airspace consolidation, and bronchiectasis) were thought to be manifestations of sequential phases of MAC disease development.