gross distortion of the normal small bowel mucosa

What does this barium follow-through show?
What is the underlying condition?

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There is gross distortion of the normal small bowel mucosa with "rose thorn" ulceration and narrowing of the bowel lumen, in the upper part showing a "string" sign ie long thin narrowing of a segment of bowel. These are features of advanced acute on chronic Crohn's disease of the terminal ileum.