String of kantor is seen in

The gastrointestinal string sign (string sign of Kantour) refers to the string-like appearance of a contrast-filled bowel loop caused by severe narrowing of a bowel loop.Originally used to describe the reversible narrowing caused by spasms in Crohn disease, it is now used for any severe narrowing of the bowel lumen, including that seen in hyperophic pyloric stenosis, gastrointestinal tuberculosis, carcinoid tumor and colon cancer.(Ref: Grainger and Allison&;s diagnostic radiology 6th edition, 662)