This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal Radiology, Subject name: Radiology
Saw tooth appearance on barium study is seen in 
Select and explain. 
A. Intussusception, B. Ileocecal TB, C. Ischemic colitis, D. Diveiculosis
D: Diveiculosis
Answer: D: Diveiculosis 
Explanation: Diveiculosis Saw-tooth appearance to the colon, usually sigmoid, with shoening of the bowel, crowding of haustra and picket-fencing of folds Ischemic colitis - thumb printing sign.