Figure 5. 52-year-old woman with marked left lower lobe and right middle lobe atelectasis with bronchiectasis. (a) Posteroanterior radiograph shows obliteration of the right cardiac border (the silhouette sign). Although the left hilum is small and the vascular markings in the left lung are decreased, it is difficult to detect the atelectatic left lower lobe. (b) Lateral radiograph shows the atelectatic right middle lobe as an oblique linear opacity. The atelectatic left lower lobe is not identified. The left hemidiaphragm is seen throughout. (c) CT demonstrates the right middle lobe atelectasis as a triangular opacity with air bronchogram. Marked left lower lobe atelectasis is seen at the left paravertebral region.
