[Can sonography give an indication of the chemical composition of gallstones?].

Eight sonographic patterns caused by gall stones are described. In an attempt to explain these different appearances, 62 stones were analysed chemically and physically. The chemical composition of the stones did not correlate with their sonographic pattern. Cholesterol stones cannot be recognised as such by sonography. The formation of an acoustic shadow depends largely on the position of the stone within the acoustic beam. It therefore follows that the examination must be done by keeping the focal plane of the transducer in proper relationship to the stone.