Understanding Lung Collapse: Identifying Asymmetry on Chest X-rays

Asymmetry caused by a collapsed lung (unilateral hyperlucency) is commonly seen on the posteroanterior (PA) chest radiograph.

- The affected side is hyperlucent (black) because there is less tissue to attenuate the x-ray beam, with loss of volume.

- The diaphragm is elevated, and tracheal deviation away from the collapsed lung is common.

- The cardiac silhouette shifts toward the side of the collapse.

- The ipsilateral lung markings are decreased or absent, and the vessels may appear crowded together.

- The ipsilateral hilum is elevated, and the ribs may be more prominent.