Diverticula of the duodenum are incidental findings in 1%-5% of barium examinations of the upper gastrointestinal tract. They are acquired lesions consisting of a sac of mucosal and submucosal layers herniated through a muscular defect in the bowel wall. They are found most commonly along the medial border of the descending duodenum where penetrating vessels cause potential weak spots in the bowel wall. Thirty to forty percent of diverticula arise in the third and fourth portions of the duodenum.

Clinical features -

Great majority of duodenal diverticula are asymptomatic. Clinical presentation may be characterized by non-specific abdominal symptoms and less than 5% of patients have abdominal symptoms. Abdominal discomfort is usually located in epigastrium, right upper abdomen or umbilical area which is made worse or brought on by eating and relieved by vomiting, belching or assuming certain posture.

Duodenal diverticulum is an incidental finding of UGI barium examination after ingestion of barium, study is made in erect, recumbent and oblique positions. One of most important feature is abnormal retention of barium in the sac. Barium retention for 6 or more hours is diagnostic. The use of a small amount of barium may help to avoid the overlapping of duodenum by jejunal loops and by the completely filled stomach. At times sac is better visualized from 1-2 hours following the opaque meals.

In upper GI series in patients with IDD, the “duodenal Wind Sock sign” may be seen. It consists of barium filled sac that lies entirely within duodenum and is surrounded by a narrow radio-luscent line which is well demonstrated as the barium in the duodenum passes distal to the diverticulum.

Duodenal wind sock sign in a patient with duodenal diverticulum. Image from an upper gastrointestinal series clearly demonstrates an intraluminal duodenal diverticulum (arrows) surrounded by a narrow radiolucent line (arrowheads). The diverticulum, arising in the second portion of the duodenum and extending to the third portion, was confirmed at surgery.

CT -

When associated with diverticulitis or perforation the CT appearance of DD include a mass like structure that is interposed between the duodenum and the pancreatic head containing air, an air fluid level, fluid, contrast material, or debris. On perforation, duodenal wall thickening and surrounding free air, fluid and fat stranding may be noted. When diverticulum is entirely filled with fluid it may mimic a cystic neoplasm arising from the head of the pancreas. Location and presence of small amount of intradiverticular gas when present may aid in establishing the diagnosis.