Crampy Abdominal Pain: Your Impression?

A 62 year-old woman presents to the hospital after the sudden onset of crampy abdominal pain followed by several bloody bowel movements.  She had a screening colonoscopy 12 years ago which was unremarkable. A CT of the abdomen is performed in the emergency room and reveals circumferential bowel wall thickening around the region of the descending colon. A colonoscopy is performed and demonstrates the image seen in the Figure.

What is the diagnosis?

Pleaese leave your impressions below then click here for answer and discussion.