[Ultrasonography and retrograde transpapillary cholangiopancreatography combined with sphincterotomy in the diagnosis of choledochal lithiasis. Our experience with 87 patients].

We retrospectively reviewed the US findings of 87 patients to assess US sensitivity in the detection of choledochal (CBD) stones. Endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy (ES) was used as the diagnostic standard, except for 1 patient who underwent surgical exploration. First, the distal CBD was studied with transverse and parasagittal US scans through the head and uncinate portions of the pancreas. CBD stones usually appeared as hyperechoic lesions, most of them with acoustic shadowing. In some cases, the stone moves during real-time scanning, which further confirms the diagnosis. Fifty-four of 87 patients had CBD stones and US detected them in 46 cases. The absence of a stone was diagnosed correctly in 28 of 33 patients. In our series, US sensitivity, specificity and accuracy were 85%, positive predictive value 88% and negative predictive value 78%. If the distal duct cannot be demonstrated adequately or if duct size is normal, US sensitivity in detecting stones decreases and other examinations, such as ERCP, should be performed. We conclude that US can be used as the diagnostic method of choice to examine the patients with suspected biliary tract disease. Although ERCP is the gold standard for diagnosis and therapeutic purposes in choledochal stones, it remains an invasive technique and must therefore be held in reserve.