Irritable bowel syndrome is one of the most common functional gastrointestinal disorders. Its main symptoms are abdominal pain and changes in the nature of stool, with the abdominal pain being related to defecation, meaning that the pain is followed by a bowel movement. Since it is a functional gastrointestinal disorder, there are no organic changes, meaning there are no physical changes in any part of the body. It is solely a functional change, and therefore cannot be detected through an ultrasound. In fact, no tests can detect the functional nature of this disorder. In terms of examining the intestinal mucosa, ultrasound cannot visualize it either. The only way to clearly see the intestinal mucosa is through a colonoscopy, so ultrasound cannot detect irritable bowel syndrome.