The imaging diagnosis of pyloric atresia.

Pyloric atresia is a congenital anomaly manifested by gastric outlet obstruction. The radiographic signs are characterised by the presence of the gas-bubble sign, the pyloric dimple sign and the absence of the beak sign. The differential diagnosis of these signs is discussed in view of other gastric outlet obstructions. Ultrasonography is of value in demonstrating the absence of the normal echo pattern of the pyloric muscle and the pyloric canal, thus confirming the diagnosis of pyloric atresia, or even may replace the fluoroscopy of the upper gastrointestinal tract.