This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdominal Radiography, Subject name: Radiology
Diamond sign is seen in- 
Select and explain. 
A. Congenital pyloric stenosis, B. Esophageal atresia, C. Intestinal obstruction, D. Colon cancer
A: Congenital pyloric stenosis
Answer: A: Congenital pyloric stenosis 
Explanation: Ans. is 'a' i.e., Congenital pyloric stenosiso Double/triple track sign is seen in congenital hypertrophic pyloric stenosis.Barium study in CHPSElongation and narrowing of pyloric canal (2-4 cm length)Passing of small barium streak through pyloric canal seen as a string of barium known as string sign.Crowding of muscle folds in pyloric canal known as double/triple track sign.Transient triangular tent-like cleftniche in mid portion of pyloric canal with apex pointing interiorly; seen due to mucosal belonging between 2 separated hypertrophied muscle bundles on greater curvature side within pyloric canal, known as diamond sign/ twining recess.Outpouching along lesser curvature due to disruption of antral peristalsis, known as pyloric teat/teat sign.Mass impression upon antrum with streak of barium pointing toward pyloric channel, known as beak sign/ antral beaking.Indentation of the base of duodenal bulb known as umbrella/kirkin/mushroom sign.Gastric hyperperistaltic waves known as caterpillar sign, a Single bubble sign.Shoulder sign : - Round indentation caused by very hypertrophied pyloric muscle.