CT findings of pulmonary non-tuberculous mycobacterial infection in non-AIDS immunocompromised patients: a case-controlled comparison with immunocompetent patients.

Objective: To describe CT findings of non-tuberculous mycobacteria (NTM) pulmonary infection in non-AIDS immunocompromised patients (ICPs) and to compare these findings with those in immunocompetent patients. Methods: From July 2000 to August 2007, 369 patients (mean age 58.3 years; 169 males and 200 females) with pulmonary NTM infection were retrospectively reviewed. Of these 369 patients, 24 ICPs (mean age 64.8 years; 15 males and 9 females) were identified. 16 patients had diabetes mellitus, and 6 patients had received long-term steroid therapy. One had received solid organ transplantation and one had received high-dose chemotherapy for haematological disease. 24 age- and sex-matched immunocompetent patients (mean age 64.6 years; 15 males and 9 females) were selected as the control group from the same registry. CT images were reviewed in consensus by three chest radiologists, who were blinded to immune status. Each lung lobe was evaluated in terms of extent of the lesion, bronchiectasis, parenchymal opacity and the presence of ancillary findings. Results: A total of 287 lobes were evaluated in ICPs and the control group. The ICPs showed a higher prevalence of ill-defined nodules, with cavities and large opacity >2cm with/without cavity (p=0.03, 0.04 and 0.02, respectively). Regardless of the immune status, the most common CT findings were bronchiectasis and ill-defined nodules without cavity. Conclusion: The most common CT findings of pulmonary NTM infection in ICPs were bronchiectasis and ill-defined nodules, similar to those in the control group. Ill-defined nodules with cavity and large opacity >2cm with/without cavity were more frequently found in ICPs. Advances in knowledge: In patients affected by NTM infection, large opacities and cavitation in pulmonary nodules are more frequent in ICPs than in immunocompetent patients.