Real-time ultrasonography during biliary surgery.

High resolution real-time B-mode ultrasound scanning using a sterile 7.5 MHz transducer was performed during operations on the biliary tract. Ultrasound is useful for locating the common bile duct in the presence of acute inflammation and other abnormal anatomy, detecting small calculi in the gallbladder with a thickened wall, measuring the caliber of the common bile duct, and identifying calculi in the common bile duct. Intraoperative ultrasonography can permit earlier and more precise appraisal of operative findings and, thereby, decrease operative time.