On pleural effusion
Q: What are the usual clues on chest X-ray to suggest subpulmonic effusions?
Answer: Following few suggests subpulmonic effusions.
- Apparent elevation of the hemidiaphragm,
- lateral displacement of the dome of the diaphragm,
- increased distance between the apparent left hemidiaphragm and the gastric air bubble
Lateral decubitus films more reliably detect smaller pleural effusions. Failure of an effusion to layer on lateral decubitus films indicates loculated pleural fluid or some other etiology causing the increased pleural density.
The film on the left at first glance doesn't appear to show fluid in the pleural space. The right hemidiaphragm is elevated, and if one looks carefully there is blunting of the right const-phrenic sulcus. Is there fluid in the pleural space? With the patient imaged with their right side down (B), fluid flows by gravity out from under the diaphragm and layers along the chest wall.