[Ultrasound in gastroenterology--liver and spleen]

Conventional B-mode and colour duplex imaging is the first choice imaging technique after history taking and physical examination and for the interpretation of laboratory parameters. In the hands of a gastroenterologist ultrasound has become an equally important diagnostic tool as endoscopy. The constantly evolving technique with its possibility of higher resolution by use of "harmonic imaging" and signal enhancement with contrast medium is the reason for a practically relevant review of the situation. Practical references will be given for diagnostics of the liver and portal system including the spleen. The significance of the sonographic diagnosis of "fatty liver" is critically discussed. The overall importance of ultrasound to distinguish different aetiologies of diffuse liver diseases is relatively low. Nevertheless, it is a very sensitive means to detect complications of liver cirrhosis. Portosystemic shunts and typical changes in blood vessel morphology can be diagnosed by colour duplex sonography and used as indirect signs of advanced damage to liver parenchyma. In addition, ultrasound has its value in the confirmation or exclusion of dilated bile ducts as well as in the detection and differentiation of circumscribed liver lesions. The characterisation of focal liver lesions by ultrasound is sufficient in typical cases. The use of ultrasound contrast media (signal enhancers) raises the rate of differentiation and can avoid the uncritical and sequential application of radiological imaging (computed tomography [CT] or magnetic resonance imaging [MRI]). If in doubt about the nature of a lesion, a histological diagnosis remains indispensable. The examination of the spleen and its feeding vessels is regularly done in cases of diffuse parenchymal liver disease when searching for its complications, e. g., portal hypertension. Focal spleen lesions can be observed especially in the context of lymphoma (infiltration) and other bone marrow diseases. Through the application of contrast media, changes of vascularisation (e. g., infarcts) can be visualised and traumatic lesions can be diagnosed more precisely.