Choledocholithiasis and cystic duct obstruction: difficult ultrasonographic diagnosis.

Ultrasonography of 53 patients with stones in either the common bile duct (CBD) or the gallbladder neck/cystic duct revealed respective sensitivities of only 30% and 29% for detection of calculi. The data, which were collected over a period of 40 months, were also analyzed with respect to our early experience (first 24 months) versus our later experience (last 16 months). Although there was no improvement in the diagnosis of gallbladder neck/cystic duct calculi (only those in the gallbladder neck could be identified), significant improvement occurred in the diagnosis of choledocholithiasis, with a sensitivity of 15% in the early period and a sensitivity of 55% in the later period. In part this was due to greater dependence upon real-time equipment and more emphasis on the examination of the distal CBD. A limiting factor in the diagnosis of choledocholithiasis was the normal caliber of the duct in 30% of these patients. Despite improved equipment and technique, ultrasonography cannot detect cystic duct obstruction, and the ultrasonographic diagnosis of CBD calculi remains difficult.