The spectrum of tuberculosis and non-tuberculous mycobacterial infection

The spectrum of radiographic findings in pulmonary infections due to M. tuberculosis (TB) and non-tuberculous mycobacteria (NTM) are being increasingly discussed, primarily as a result of the increasing prevalence of these infections. The NTM organisms are often overlooked as potential infecting organisms, diagnosis is often delayed and radiologists tend not to include NTM in their differential diagnosis. The literature on the imaging appearances of NTM pulmonary infections is now sufficiently large as to identify some features that would help to distinguish an NTM infection from conventional pulmonary tuberculosis, allowing the radiologist at least to raise the possibility of NTM infection. This review article is intended to describe the radiological features, in the immunocompetent host, that accompany TB and NTM pulmonary infections and highlight the imaging features that would favour an NTM as the causative organism.