[Imaging of the small intestine: current knowledge]

Imaging of the small intestine is most challenging in daily routine. With endoscopy (including balloon enteroscopy) and modern high resolution imaging methods, e.g., ultrasound (US), magnetic resonance imaging (MRI) and computed tomography (CT), the gastroenterologist has ideal complementary methods available. Radiation exposure has to be kept in mind using CT and conventional X-ray-techniques. Therefore, most importantly ultrasound and MRI have changed the routine diagnostics of intestinal diseases. The three methods are not only assessing the lumen but similarly important also the wall and the surrounding structures of the small intestine. Furthermore functional processes can be visualized and provide important information about passage and perfusion which is mainly true for the real-time technique ultrasound. Balloon enteroscopy is the method of choice to examine the mucosa and luminal aspects and to achieve histological proven diagnosis by biopsy. The future role of capsule techniques has not yet been determined. This article addresses the endoscopist, radiologists and ultrasonographer interested in small intestinal disease. The authors give an overview of the actual significance of each method imaging the small intestine. After comments on the methods the typical indications are discussed.