Ultrasonographic screening of the common hepatic duct in symptomatic patients after cholecystectomy

The role of sonography in imaging of the biliary tract

Sonography is the recommended initial imaging test in the evaluation of patients presenting with right upper quadrant pain or jaundice. Dependent upon clinical circumstances, the differential diagnosis includes choledocholithiasis, biliary stricture, or tumor. Sonography is very sensitive in detection of mechanical biliary obstruction and stone disease, although less sensitive for detection of obstructing tumors, including pancreatic carcinoma and cholangiocarcinoma. In patients with sonographically documented cholelithiasis and choledocholithiasis, laparoscopic cholecystectomy with operative clearance of the biliary stone disease is usually performed. In patients with clinically suspected biliary stone disease, without initial sonographic documentation of choledocholithiasis, endoscopic ultrasound or magnetic resonance cholangiopancreatography is the next logical imaging step. Endoscopic ultrasound documentation of choledocholithiasis in a postcholecystectomy patient should lead to retrograde cholangiography, sphincterotomy, and clearance of the ductal calculi by endoscopic catheter techniques. In patients with clinical and sonographic findings suggestive of malignant biliary obstruction, a multipass contrast-enhanced computed tomography (CT) examination to detect and stage possible pancreatic carcinoma, cholangiocarcinoma, or periductal neoplasm is usually recommended. Assessment of tumor resectability and staging can be performed by CT or a combination of CT and endoscopic ultrasound, the latter often combined with fine needle aspiration biopsy of suspected periductal tumor. In patients whose CT scan suggests hepatic hilar or central intrahepatic biliary tumor, percutaneous cholangiography and transhepatic biliary stent placement is usually followed by brushing or fluoroscopically directed fine needle aspiration biopsy for tissue diagnosis. Sonography is the imaging procedure of choice for biliary tract intervention, including cholecystostomy, guidance for percutaneous transhepatic cholangiography, and drainage of peribiliary abscesses.

Transabdominal sonography of bile ducts

Ultrasound is considered to be the initial imaging modality of choice for evaluation of bile ducts. In this article, sonographic anatomy of the bile ducts and ultrasound findings in congenital, inflammatory, neoplastic, and other abnormalities of bile ducts are described. Roles of color Doppler ultrasound and newer applications, such as harmonic imaging and three-dimensional ultrasound, in evaluation of bile ducts are discussed.

Postoperative bile duct strictures: ultrasound and endoscopic retrograde cholangiopancreatography/percutaneous transhepatic cholangiography evaluation

This retrospective study was undertaken to assess the role of ultrasound (US) and to compare it with endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC) in the evaluation of post-operative common bile duct (CBD) strictures. Seventy-four patients with postoperative CBD strictures were evaluated by ERCP and/or PTC. Of these, US scans were available in 52 patients. Ultrasound findings of CBD strictures were: proximal dilatation of CBD with smooth tapering stenosis (41%); abrupt cut off of CBD (18%); and echogenic nodule, without acoustic shadowing, in 16%. Of the remainder, mild proximal dilatation of the CBD was seen in 6%, and 19% of the patients had normal US scans.

Intrahepatic versus extrahepatic cholestasis. Discrimination with biliary scintigraphy combined with ultrasound

Biliary scintigraphy and ultrasound imaging were performed in 52 patients with suspected biliary tract pathology. Results were correlated with the findings of direct cholangiography. Several new innovations in scintigraphic technique were used. The combination of ultrasound imaging and scintigraphy correctly identified biliary tract obstruction in 17 of 19 patients, 12 of whom had dilated bile ducts on ultrasonography. Intrahepatic cholestasis was correctly diagnosed in 11 of 13 patients. Accurate discrimination between intrahepatic and extrahepatic cholestasis was achieved in 28 of 32 patients (88%) with the combined studies. Scintigraphy also provided a correct diagnosis of acute cholecystitis in all 9 patients with surgically confirmed disease. Eleven additional patients with gallbladder or pancreatic disease had normal bile ducts at scintigraphy, which was confirmed with cholangiography. When combined with ultrasound imaging, modern biliary scintigraphy can (a) provide excellent discrimination between intrahepatic and extrahepatic cholestasis and (b) help determine the need for subsequent invasive diagnostic studies in selected patients.

Ultrasound detection of choledocholithiasis: prospective comparison with ERCP in the postcholecystectomy patient

The role of ultrasound as a screening test for choledocholithiasis was prospectively assessed by comparing the results of upper abdominal ultrasound with direct cholangiography in 59 unselected symptomatic postcholecystectomy patients. Ultrasound detected duct stones in 13 of 29 patients (sensitivity, 45%) and their absence in 29 of 30 (specificity, 97%). A positive ultrasound diagnosis of choledocholithiasis was correct 13 times out of 14 (predictive value, 93%) whereas a negative diagnosis was correct on only 29 of 45 occasions (predictive value, 64%). No significant learning effect was seen. Intestinal gas obscuring the distal common duct was the most important factor limiting the ability of ultrasound to detect duct stones. Duct stones were present in 25 of 35 patients shown to have a dilated common duct on ultrasound, and in 4 of 24 with nondilated ducts; the predictive value of duct dilatation at ultrasound for duct stones was therefore 71% and that of nondilatation in excluding stones was 83%. Dilated intrahepatic bile ducts were demonstrated at ultrasound in only 17% of patients with choledocholithiasis. We conclude that ultrasound cannot reliably diagnose or exclude bile duct stones and is an inadequate screening test for the symptomatic postcholecystectomy patient.

Sister-chromatid exchanges in mouse embryos after exposure to ultrasound in utero

Mouse embryos at 2 stages of development were exposed to ultrasound. The bone-marrow cells of the mother, the whole embryo, and the embryonic liver cells were analyzed. There was no consistent increase of sister-chromatid exchanges. Furthermore, the thermal effect of ultrasound did not appear to influence the frequency. Thus, ultrasound doses much higher than those used in clinical diagnosis do not induce cytogenetic damage as assayed by sister-chromatid exchanges.