SF 6 is used as a contrast agent for ultrasound imaging. Sulfur hexafluoride microbubbles are administered in solution through injection into a peripheral vein. These microbubbles enhance the visibility of blood vessels to ultrasound.F 6 is used as a contrast agent for ultrasound imaging. Sulfur hexafluoride microbubbles are administered in solution through injection into a peripheral vein. These microbubbles enhance the visibility of blood vessels to ultrasound.
Once constipation (no bowel movement) has gone on for some time, the result can be what is known as an impacted bowel (sometimes called fecal impaction). Essentially, this means that a large lump of dry, hard stool is stuck inside your rectum.
Just because you don't have a bowel movement every day doesn't mean you're constipated. Some people have a bowel movement two to three times a day, others every three days. If you go for more than three days without one, however, your stool may harden, making it more difficult to eliminate. In rare cases, new or progressively worse constipation may be a symptom of another, more serious problem, such as colorectal cancer or medication toxicity.