FIGURE 4.

A 61-year-old man with usual interstitial pneumonia (UIP) proven by the clinical–radiological diagnosis as well as an incidental pulmonary nontuberculous mycobacterial infection detected during the UIP follow-up. (A) The initial, null, high-resolution CT transverse image lung window (1-mm reconstruction) at the basal segmental pulmonary artery level shows no significant main opacity. There are diffuse reticulation, ground-glass opacity, and air cysts with subpleural dominancy, all of which show a UIP pattern. (B) At the time of the follow-up 10 months later, a CT transverse image in the lung window (1-mm reconstruction) obtained following steroid therapy and at the same level, shows newly appearing, unusually shaped consolidation with a thick irregular cavity in the midst of fibrotic cysts compared to that seen on the null CT image (A). CT = computed tomography.