Clinical indications and accuracy of gray scale ultrasonography in the patient with suspected biliary tract disease.

One hundred patients with suspected biliary tract disease underwent gray scale cholecystosonography (GSCS) and had diagnostic confirmation by oral cholecystogram (OCG) and/or operation. Ultrasonography demonstrated the gallbladder in 94 of the 100 patients; 2 patients had had previous cholecystectomy and 3 of the 4 remaining patients had documented stones with no confirmation of a nonvisualizing OCG in the other patient. Among the 88 patients with OCG, GSCS findings correlated in 91 per cent (2 per cent false-positive; 7 per cent false-negative). Among the 43 operative patients, GSCS was proven correct in 91 per cent (no false positive; 9 per cent false-negative). Of 12 patients with jaundice GSCS correlated with operative findings in 75 per cent (no false-positive; 25 per cent false-negative). Diagnostic errors occurred in patients with very small biliary calculi, particularly when a single stone was impacted in the cystic duct. Failure to identify the gallbladder with ultrasound signifies probable cholelithiasis in the patient without previous cholecystectomy. On the basis of this experience, we conclude that (1) GSCS is most useful when jaundice or acute illness precludes conventional studies; (2) GSCS provides an inexpensive, quick, accurate means of diagnosing cholelithiasis with a very high specificity (97 per cent) and moderate sensitivity (88 per cent); and (3) GSCS is the optimal diagnostic procedure for evaluating the biliary tract in the acutely ill, jaundiced, vomiting, allergic, and/or pregnant patient.