Final answer:
The GI disease that has a string sign on an x-ray is gastric outlet obstruction. The string sign is a radiographic finding that indicates a narrowing or constriction of the stomach or proximal duodenum. It is useful in diagnosing and assessing the severity of gastric outlet obstruction.
Step-by-step explanation:
The GI disease that has a string sign on an x-ray is gastric outlet obstruction.
The string sign is a radiographic finding that indicates a narrowing or constriction of the stomach or proximal duodenum. It appears as a narrow, linear filling defect on the x-ray. This can be caused by conditions such as peptic ulcer disease, gastric cancer, or pyloric stenosis.
The string sign is useful in diagnosing and assessing the severity of gastric outlet obstruction, as it helps determine the presence and location of the narrowing.