What radiological finding is characterized by blunting or obliteration of the costophrenic angles?

The radiological finding characterized by blunting or obliteration of the costophrenic angles is associated with pleural effusion. When fluid accumulates in the pleural space, it can cause the costophrenic angles, which are the angles formed where the diaphragm meets the ribs, to appear obscured or blurred on imaging studies like chest X-rays. This is because the presence of fluid disrupts the normal anatomical outlines seen in healthy lungs.

In contrast, other conditions such as pneumonia might show signs of inflammation or consolidation but would not specifically cause blunting of the costophrenic angles. ARDS (Acute Respiratory Distress Syndrome) or IRDS (Infant Respiratory Distress Syndrome) can lead to diffuse alveolar damage and increased opacity across the lungs, but again, this does not specifically result in blunting of the costophrenic angles like a pleural effusion does. Similarly, pulmonary embolism might have indirect effects on lung structure and blood flow, but it does not typically present with this specific radiological finding.

Therefore, the recognition of blunting or obliteration of the costophrenic angles is a key indicator in diagnosing pleural effusion based on radiological evidence.