- CT scans produce detailed images of the entire bowel but expose you to radiation and use contrast dye that some people cannot tolerate.
- MRE closely examines the small intestine but is expensive, time-intensive, and requires fasting and oral contrast (which some people cannot tolerate). It can also be difficult for people with implanted medical devices or claustrophobia, and may be contraindicated in others.
- Colonoscopy uses a flexible tube with a light on the end to show the entire large intestine and end of the small intestine (terminal ileum) and allows for biopsies and cancer screening. But it is invasive, requires sedation and bowel preparation using laxatives, and carries a small risk of bleeding, infection, or a tear in the bowel wall.
Intestinal ultrasound avoids many of these challenges. It’s safe, noninvasive, requires no fasting or bowel preparation, and provides results quickly. “Intestinal ultrasound has truly transformed the way I care for my patients with inflammatory bowel disease,” says Bincy Abraham, MD, the director of the Fondren Inflammatory Bowel Disease Program at the Underwood Center for Digestive Disorders at Houston Methodist Hospital in Texas and the president of the Strategic Alliance for Intercultural Advocacy in GI (SAIA-GI).
“Since it allows me to assess disease activity in the bowel in real-time during a clinic visit, my patients feel they have immediate answers and reassurance of how treatment is going. They also feel quite engaged in their care,” she says.
Research shows intestinal ultrasound is nearly as accurate as MRE scans. In one study of people with Crohn’s disease, MRE accurately detected disease activity in the terminal ileum 97 percent of the time, while intestinal ultrasound detected it 94 percent of the time.
Other research on Crohn’s has found that intestinal ultrasound performs better than MRE at detecting inflammation and thickening of the bowel wall, narrowing (stenosis), and fluid buildup (ascites).
Intestinal ultrasound does have some limitations: It is not ideal for examining the entire small intestine and is not a replacement for colonoscopy when screening for colorectal cancer. Instead, it serves as a complementary tool.
“Ultrasound is like taking a magnifying glass to specific parts of the bowel, and an MRE or CT scan is like you’re in a plane flying over a city and you can see the entire map and landscape of everything. Both are extremely valuable,” says Dr. Dolinger.
