What does a chest X-ray (CXR) typically show in the case of pleural effusion?

In cases of pleural effusion, a chest X-ray typically reveals blunting of the costophrenic angle. This blunting occurs because the pleural fluid accumulates in the pleural space, which is the area between the pleura lining the lungs and the chest wall. When fluid builds up, it causes the normally sharp angle at the bottom of the lung to become rounded or obscured, making this finding a classic sign of pleural effusion on radiographic imaging.

The presence of blunted costophrenic angles is often assessed by comparing the angles on both sides of the chest; in normal circumstances, these should be clearly defined. As the amount of pleural fluid increases, the blunting becomes more pronounced, and if large amounts of fluid are present, a meniscus may be visible along the pleural fluid's upper border.

The other options typically do not indicate pleural effusion. Clear lung fields with normal lung markings would suggest no significant pathology, while prominent vascular markings may indicate conditions like pulmonary congestion rather than an effusion. Lastly, elevation of the diaphragm can occur but is not a definitive sign of pleural effusion; it can result from a variety of other conditions. Therefore, blunting of the cost