Progressing features of atypical mycobacterial infection in the lung on conventional and high resolution CT (HRCT) images.

Abstract

PURPOSE: The aim of this study was to clarify the localization of abnormalities within secondary pulmonary lobules and the changes in follow-up studies of pulmonary atypical mycobacterial infection (AMI) by conventional and high-resolution computed tomography (HRCT). MATERIALS AND METHODS: Forty-six patients (16 men and 30 women; 43-84 years) with pulmonary AMI (M. intracellulare 36; M. avium 10) in the lung were examined by conventional and HRCT. RESULTS: In peripheral zones, all patients had the nodule located in the terminal or lobular bronchiole, and most of the patients also had nodules accompanied with a wedge-shaped or linear shadow connected with the pleura. In the follow-up scans, new centrilobular nodules appeared in other segments, and consolidation or ground-glass pattern appeared newly and was preceded by nodules. Bronchiectasis became more severe in five of 38 follow-up patients. CONCLUSION: The common HRCT findings of AMI were centrilobular, peribronchovascular nodules, bronchiectasis, consolidation, and pleural thickening/adhesion. The nodules frequently connected with the pleura. The initial and follow-up studies suggest that the disease may begin in the terminal bronchiole or as preexisting bronchiectasis and spread transbronchially along the draining bronchus or towards the pleura to produce lesions such as new nodules, cavities, consolidation, pleuritis, and bronchiectasis, or more severe bronchiectasis.