Nontuberculous Mycobacterial (NTM) Disease in Immunocompetent Patients: Expanding Image Findings on Chest CT

Purpose: The aim of this study was to evaluate the chest CT features of nontuberculous mycobacterial (NTM) disease regardless of the specific organisms. Materials and Methods: This study included 74 consecutive patients (35 men, 39 women; mean age, 63 years; age range, 25-89 years) who were diagnosed with NTM disease according to the American Thoracic Society Guidelines (1997 and 2007) between January 2005 and July 2007. Chest CT images were randomly reviewed by two radiologists with consensus. Results: The most common organism associated with NTM disease is M. avium-intracellulare complex (87.8%), followed by M. abscessus, M. kansasii, and M. chelonae. The most common chest CT finding was a nodular bronchiectatic lesion (n = 35, 46.7%), followed by a cavitary lesion of the upper lobe (n = 21, 28.0%), combined lesions of two prior subtypes (n = 6, 8.0%), consolidative lesion (s) (n = 5, 6.7%), a bronchogenic spreading pulmonary tuberculosis-like lesion (n = 5, 6.7%), a cavitary mass lesion with small satellite nodules (n = 2, 2.7%), and a miliary nodular lesion (n = 1, 1.3%). More than 5 segments were involved in 60 cases (81.1%). Conclusion: The nodular bronchiectatic lesion or cavitary lesion of upper lobe presents with multi-segmental involvement and the occurrence of combined consolidation is indicative of NTM disease.