Question

What type of negative contrast agent is administered rectally for virtual colonoscopy studies?

1) CO₂
2) water
3) barium sulfate oral agents
4) iodinated oral agents

Answer 1

CO₂ is the negative contrast agent used rectally for virtual colonoscopy studies, helping in clear visualization of the colon.

Step-by-step explanation:

The type of negative contrast agent that is administered rectally for virtual colonoscopy studies is CO₂. It is used because it distends the colon, which allows for better visualization during the imaging process. In contrast, barium sulfate and iodinated oral agents are typically used as positive contrast agents for other types of medical imaging, such as traditional X-rays, where they coat the intestinal tract to provide greater visual detail, aiding in the diagnosis of conditions such as acid reflux disease, Crohn's disease, and ulcers.