system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
X-ray feature of pyloric stenosis is -
assistant
The correct answer is  The plain XR will show a "single bubble" with air in a distended stomach. An elongated and narrowedpyloric canal (2-4cm in length) results in a "string" sign when a small amount of barium streaks through the pyloric canal