A barium enema, also called a lower GI series, uses which imaging modality?

• A. CT scan
• B. Fluoroscopy
• C. MRI
• D. Ultrasound

Answer: (B)

Fluoroscopy is the imaging modality used for a barium enema because this exam relies on real-time X-ray visualization as the radiopaque barium contrast moves through and coats the colon. This dynamic imaging lets the radiologist observe how the bowel fills, expands, and empties, making it possible to spot polyps, diverticula, diverticular disease, strictures, and other mucosal or luminal abnormalities as they occur live.

Other imaging options aren’t used for the standard lower GI series. CT scans provide cross-sectional images and are used for CT colonography or other abdominal assessments, not the traditional enema study. MRI isn’t the typical choice for this procedure, and ultrasound isn’t ideal for viewing the gas-filled colon and is rarely used for this purpose.