US of gastrointestinal tract disease.

The potential use of ultrasonography (US) in evaluating gut disease has been underappreciated in most diagnostic imaging departments in North America. The impression that US has a questionable role in bowel assessment is related to the operator-dependent nature of the modality, the technical challenges of performing bowel US examinations, and the lack of familiarity of radiologists and technologists with the US appearances of normal and abnormal bowel. However, with development of technical experience by the sonographer and integration of a clinical focus at patient evaluation, US can become a powerful tool for bowel assessment. Unlike computed tomography and magnetic resonance imaging, it provides a widely available, noninvasive, inexpensive method for evaluating the gut without the use of ionizing radiation. These factors are of particular importance in young patients and those who require recurrent follow-up imaging. Because US is performed with real-time imaging, the modality also allows the sonographer to view and assess the motility properties of the bowel, a feature that has not been previously used to its full potential. Color Doppler US can yield useful information about mural vascularity in bowel disease when used in conjunction with gray-scale findings and clinical symptoms. Radiologists should be familiar with the static and dynamic US appearances of the normal and abnormal bowel, recognize features of various pathologic conditions, and understand potential errors at imaging interpretation. Online supplemental material is available for this article.