Figure 1.

A 54-year-old male with a pulmonary lesion identified on a routing chest computed tomographic scan. Axial lung window (A), axial soft-tissue window (B), and minimum-intensity-projection (MinIP) lung window coronal (C), and sagittal (D) contrast-enhanced CT images show a dilated, club-like structure surrounded by emphysematous changes of the peripheral lung fields at the superior segment of the left lower lobe; computerized tomography number is 28 HU; non-enhancement of the structure is shown on contrast-enhanced CT. The orifice of the superior segmental bronchus was not observed. CT features indicate a diagnosis of bronchial atresia. E, F, G, H are the corresponding normal control CT findings of A.B, C, D.