The Value of Contrast-Enhanced Ultrasound-Guided Contrast Injection via the Endoscopic Nasobiliary Drainage Duct in Diagnosing Residual Common Bile Duct Stones

Objectives. To investigate the diagnostic value of contrast-enhanced ultrasound- (CEUS-) guided contrast injection via an endoscopic nasobiliary drainage (ENBD) tube on the evaluation for residual stones in common bile duct (CBD). Methods. 116 patients with CBD stones were treated by endoscopic retrograde cholangiopancreatography and duodenoscopic sphincterotomy incision surgery and ENBD. The US group consisted of 54 patients who underwent US-guided saline injection via the ENBD tube to evaluate for residual CBD stones. The CEUS group consisted of 62 patients who underwent CEUS-guided contrast injection via the ENBD tube to evaluate for residual CBD stones. The length and width of CBD and the detection rate of residual stones before and after NS injection were compared. Results. In both the US group and the CEUS group, the rate of complete demonstration and the average length and width of CBD before and after injection of NS were all increased significantly. In the US group, 6 patients had verified residual stones, 1 of which was detected by conventional US (detection rate, 1/6), 5 of which were detected by saline injection ultrasound (detection rate, 5/6), and 4 of which were detected by ENBD cholangiography (detection rate, 4/6). There was 1 false positive result on saline injection US and 2 false positives on ENBD cholangiography. In the CEUS group, 6 patients had verified residual stones, none of which were detected by conventional US (detection rate, 0/6), all of which were detected by saline injection CEUS (detection rate, 6/6), and 4 of which were detected by ENBD cholangiography (detection rate, 4/6). There was 1 false positive result on ENBD cholangiography. Conclusions. CEUS-guided contrast injection via an ENBD tube helps to provide clear observation of residual stones in the CBD after ERCP with EST and provides comprehensive information for follow-up.