PURPOSE. We retrospectively evaluated sonographic findings in 946 cases of gallstones to determine whether the false-negative rate for gallstone detection by sonography has decreased as a result of technologic advances over the past 15 years.
Methods: We reviewed preoperative sonographic reports, operative notes, and pathologic reports for 614 women and 332 men (ages 22-78 years) seen over a 2.5-year period and compared sonographic findings with surgical pathologic findings after cholecystectomy. Sonograms for patients whose gallstones were missed on sonography were reviewed by 3 board-certified radiologists.
Results: Preoperative sonography of the gallbladder accurately predicted the presence of gallstones in 934 cases (98.7%). Gallstones were not identified by sonography in the remaining 12 cases. In those cases, sonography revealed polyps in 5, sludge in 5, sludge plus a polyp in 1, and neither stones nor polyps in 1. Thus, the false-negative rate was 1.3%.
Conclusions: Despite improvements in sonographic technology, detection of small gallstones remains difficult in some cases. Adherent gallstones can mimic gallbladder polyps. Our false-negative rate for detection of gallstones was no different from that in earlier studies.