The efficacy of endoscopic ultrasound for the diagnosis of common bile duct stones as compared to CT, MRCP, and ERCP.

Biliary stone disease is one of the most common medical conditions that can lead to hospitalization and surgical intervention. Choledocholithiasis develops in approximately 10e20% of patients with gallbladder stones, while approximately 3e10% of patients undergoing cholecystectomy will have common bile duct (CBD) stones. The CBD stones can cause cholangitis, obstructive jaundice, acute pancreatitis and sepsis. Therefore, accurately diagnosing choledocholithiasis is important for clinical decision making. Clinical predictors for choledocholithiasis include elevated bilirubin, clinical ascending cholangitis or gallstone pancreatitis, and dilated CBD on transabdominal ultrasound (US). However, clinical presentations and biochemical tests are often insufficient, and imaging studies are always necessary to confirm the diagnosis. Currently, abdominal US, endoscopic ultrasonography (EUS), endoscopic retrograde cholangiopancreatography (ERCP), computed tomography (CT), CT cholangiography, magnetic resonance cholangiopancreatography (MRCP), and intraoperative fluorocholangiography are available imaging modalities for the detection of CBD stones. In most hospitals, abdominal US and CT are still the threshold imaging studies for patients with abdominal pain. However, the sensitivity of transabdominal US for detection of CBD stones is only 26%. The sensitivity and specificity of unenhanced helical CT in detecting CBD stones is reported to be 50e88% and 84e98%, respectively. The multi-slice CT has resulted in a transformation from cross-section imaging to true three-dimensional images. Reconstruction CT images have become routine in clinical practice; however, the coronal reconstruction of CT imaging did not increase its diagnostic efficacy on choledocholithiasis. Primarily, stone size affects the diagnostic rate of abdominal CT for detecting choledocholithiasis. The CT diagnostic rate was significantly lower in patients with choledocholithiasis of less than 5 mm than in patients with choledocholithiasis of 5 mm or more (56.5% vs. 81.2%). MRCP can also provide excellent anatomical detail of the biliary and pancreatic ducts, thus increasing the diagnostic efficacy of CBD stones. MRC was reported to have 85e92% sensitivity and 93e97% specificity for detection of choledocholithiasis. However, the stone size also affects the diagnostic rate of MRC for choledocholithiasis. The sensitivity decreased to 33-71% in the setting of small CBD stones