Figure 6. 22-year-old man with marked right middle lobe atelectasis due to bronchiectasis. (a) Posteroanterior (PA) radiograph shows obliteration of the right cardiac border, but the finding is rather subtle. (b) Lateral radiograph shows a thin linear opacity (arrowheads). The diagnosis of right middle lobe atelectasis cannot be clearly made from PA and lateral views. (c) Apical lordotic radiograph demonstrates the atelectatic right middle lobe as a triangular opacity. Note the air bronchogram within the atelectatic lobe, indicating non-obstructive atelectasis.