Left lateral decubitus sonography of gallstones in the contracted gallbladder.

A prospective study of the accuracy in diagnosing gallstones using ultrasonography in the absence of a fluid-filled gallbladder was done over a 20 month period; 91 patients were studied. A focal echo complex with acoustic shadowing was shown to be a highly reliable criterion for diagnosing gallstones in a contracted gallbladder when (1) it was demonstrated on longitudinal, transverse, and left lateral decubitus views, and (2) the configuration of the echo complex remained the same.