A lower GI series uses x rays to help diagnose problems of the large intestine, which includes the colon and rectum. A lower GI series is sometimes called a barium enema because the large intestine is filled with barium liquid. The barium liquid coats the lining of the large intestine and makes signs of disease show up more clearly on x rays.
Image Source: NIH
A lower GI series can detect problems of the large intestine, including
• diverticula—bulges in the intestinal wall
• cancerous growths
• fistulae—abnormal openings in the intestinal wall that lead to the abdominal cavity, other organs, or the skin’s surface