Comparative appearances of non-tuberculous mycobacteria species: a CT study

Abstract

Our objective was to characterise the CT features of the various species of non-tuberculous mycobacteria (NTM) and to identify differences, if any, between Mycobacterium avium intracellulare( MAI) and other species. Fifty-five patients, who were culture positive on at least two occasions for a single NTM species, were evaluated. All patients had CT scans performed within 6 months of NTM identification. The CT scans were assessed for the presence and severity of bronchiectasis, nodules, cavities, tree-in-bud pattern, consolidation and for evidence of pre-existing lung disease. Bronchiectasis was identified in most patients (52 of 55, 95%) and nodules were present in approximately half (29 of 55, 53%). Patients with MAI ( n=16) were found to have significantly higher bronchiectasis scores and higher prevalence of nodules than the other species (both p<0.01). Patients with M.kansasii ( n=9) and M.xenopi ( n=9) had cavities, tree-in-bud pattern, and pre-existing emphysema as the dominant CT features. Patients with M.chelonae and M.fortuitum were younger than the other groups and also had a high incidence of pre-existing lung disease. Patients with MAI infection have more severe bronchiectasis and more nodules on CT than the other NTM species. Morphological differences between the other species were identified but were less distinct.

Nontuberculous mycobacterial disease and Aspergillus-related lung disease in bronchiectasis

“…However, they may be encountered in severe bronchiectasis, such as CF, as a result of chronic bacterial infection and might therefore be inappropriate as selective criteria for diagnosis [21]. NTM infection, especially MAC infection, can give rise to bronchiectasis and pulmonary infiltrates, as seen in ABPA [10,11,22]. In view of this, the present authors did not attempt to review CT scans for evidence of ABPA but relied on combined clinical and serological criteria as recommended for patients with CF [21].…”

“…NTM disease itself may prove difficult to diagnose due to its nonspecific clinical and radiographical presentation, although characteristic radiographical features of some NTM species have been described [10][11][12]. NTM infection and concomitant Aspergillus-related lung disease have been reported previously.…”

Nontuberculous Mycobacterium Infections in Rheumatoid Arthritis Patients

“…The HRCT findings of MAC-PD also exhibit all three forms of lung disease, as described for NTM-PD, namely cavitary disease, fibronodular bronchiectasis, and HP (Cappelluti et al, 2003;Embil et al, 1997;Glassroth, 2008;Kahana et al, 1997). Fibronoduar bronchiectasis caused by MAC is most frequently observed in women >60 years old, and compared to patients with other types of NTM infection, the lingual and right middle lobe tend to be more severely and progressively involved (Hollings et al, 2002;Kim et al, 2005;Kubo et al, 1998;Obayashi et al, 1999;Prince et al, 1989;Tanaka et al, 2001). In a recent clinical study, MAC was cultured from the sputum of 25% of the patients with fibronodular bronchiectasis, and MAC infection was documented in 50% of bronchoscopies, including BAL and transbronchial biopsies (Griffith et al, 2007).…”

Tuberculosis and Nontuberculous Mycobacterial Infections in Older Adults

“…Computerized tomography (CT), particularly using the high-resolution technique (HRCT), has dramatically altered the understanding of pulmonary disease caused by MAC, and this is an extremely helpful tool in the evaluation of patients with M. avium complex in respiratory secretions. HRCT studies demonstrate that disease is generally more diffuse than generally appreciated on the basis of plain chest radiographs (47)(48)(49). In addition, HRCT studies often demonstrate what have come to be viewed as characteristic findings of MAC infection, namely, multiple small nodules and associated bronchiectasis (48,50,51).…”