Ultrasound examination of the sigmoid colon: possible new diagnostic tool for irritable bowel syndrome

Irritable bowel syndrome (IBS) affects about 10% of the population, and is primarily a disease of women. It may cause chronic pelvic pain. As yet there is no imaging test to aid in diagnosis, which relies upon history. We aimed to determine whether transvaginal sonographic investigation of the sigmoid colon could aid in the diagnosis of IBS.

Transvaginal ultrasound was used in 175 female patients undergoing pelvic ultrasound studies for a variety of reasons, none specifically for bowel complaints. We measured the wall of the sigmoid colon and then obtained the history of positive or negative for IBS.

The majority of those 27 reporting a history of IBS had thickening of the wall of the sigmoid colon. A cut-off of 3.0 mm gave a sensitivity for this group of patients of 70%, specificity of 95%, positive predictive value of 73% and negative predictive value of 95%.

Transvaginal ultrasound may be useful in identifying patients at risk for IBS. Consideration of colon wall measurement during pelvic ultrasound should be studied, as IBS may be a cause of chronic pelvic pain.