Figure 3. 20-year-old man with marked right lower lobe atelectasis due to bronchiectasis as a result of childhood pulmonary infection. (a) Posteroanterior radiograph. The atelectatic right lower lobe is so small that it can hardly be seen. The right hilum is small, and compensatory overinflation and decreased vascular markings in the right lung are present. Note that the anterior mediastinal triangle has shifted to the right (black and white arrowheads), forming the upper triangle sign. (b) Lateral radiograph. The atelectatic lobe cannot be identified. Note that the right hemidiaphragm is seen throughout. (c) CT shows a small opacity with air bronchogram at the right paravertebral region (arrow).
