High accuracy sonographic recognition of gallstones.

Recent advances in the imaging capabilities of gray scale sonography have increased the accuracy with which gallstones may be diagnosed. Since the sonographic diagnosis of gallstones is often followed by surgery without further confirmatory studies, the avoidance of false-positive diagnoses assumes major importance. In an attempt to improve diagnostic accuracy, 420 gallbladder sonograms were evaluated for gallstones. Positive diagnoses were limited to cases in which the gallbladder was well visualized and contained densities that produced acoustic shadowing or moved rapidly with changes in position. Gallstones were diagnosed in 123 cases and surgery or autopsy in 70 of these patients confirmed stones in 69. There was one false-positive, an accuracy rate for positive diagnosis of 98.6%. Five cases were called indeterminate for stones; one of these had tiny 1 mm stones at surgery. The other four cases had no surgery. Of 276 cases called negative for stones. None of the 146 cases with negative sonograms and oral cholecystography or intravenous cholangiography had stones diagnosed by these methods. Because of its ease and simplicity, sonography is attractive as the initial study in patients suspected of having gallstones. With the criteria used here, a diagnosis of gallstones in the gallbladder can be offered with great confidence.