X-Ray feature of pyloric stenosis is
**Core Concept**
Pyloric stenosis, a condition characterized by the narrowing of the pyloric channel, often presents with non-bilious vomiting in infants. The X-ray feature of pyloric stenosis is a key diagnostic clue, which involves the visualization of a characteristic "olive" or "bullseye" sign on the abdominal X-ray.
**Why the Correct Answer is Right**
The "olive" or "bullseye" sign is due to the thickened pyloric muscle, which is seen as a concentric ring of muscle around a central area of thin mucosa. This appearance is a result of the hypertrophied pyloric muscle, which is a hallmark of pyloric stenosis. The X-ray is taken with the patient in the upright position, which helps in visualizing the pyloric channel more clearly.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not describe a characteristic X-ray feature of pyloric stenosis.
**Option B:** This option is incorrect because it describes a feature of gastric outlet obstruction, which is a different condition.
**Option C:** This option is incorrect because it describes a feature of intussusception, which is a different condition.
**Clinical Pearl / High-Yield Fact**
To remember the "olive" or "bullseye" sign of pyloric stenosis, recall that it resembles a target or a bullseye, with the hypertrophied pyloric muscle forming the concentric rings.
**Correct Answer: D. The "olive" or "bullseye" sign.**