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.
Signs and Symptoms. Although bowel movement frequency varies greatly for each person, if more than three days pass without a bowel movement, the contents in the intestines may harden, making it difficult or even painful to pass. Straining during bowel movements or the feeling of incomplete emptying also may be considered constipation. Constipation is a symptom, not a disease, and can be caused by many factors. The most common are poor diet and lack of exercise. Other causes include irritable bowel syndrome, pregnancy, laxative abuse, travel, specific diseases, hormonal disturbances, loss of body salts and nerve damage.