Chest X-ray pulmonary oedema refers to the radiographic appearance of excess fluid in the lung interstitium and alveoli, typically seen as bilateral opacities on a chest X-ray. This finding is clinically significant as it indicates underlying conditions such as heart failure, pneumonia, or acute respiratory distress syndrome, necessitating prompt diagnosis and management. A key association is with congestive heart failure, where pulmonary oedema can lead to respiratory distress and impaired gas exchange.