Imaging Studies

Ultrasound

1. Often used as the first evaluation procedure for suspected biliary tract disease, along with ALP assay.

2. Blockage of the biliary tree leads to dilation of the ducts proximal to the blockage; the dilated ducts can be visualized and measured by ultrasound.

3. Stones may also be visualized in the duct by ultrasound.

Biliary tract and hepatic radionuclide scanning

1. Labelled IDA (iminodiacetic acid) is taken up by the liver and excreted into the bile.

2. This is the current procedure of choice for diagnosis of acute cholecystitis.

3. Failure to visualize the gallbladder with the label is diagnostic of acute cholecystitis with cystic duct blockage.

4. Similar methods are used in hepatic scanning: labeled colloidal particles are taken up by Kupfer cells in the liver and can be used to visualize metastases as “filling defects” (note the defect in the superior right lobe of this scan).

5. Liver scans are useful to distinguish a diffusely enlarged liver from one that contains discrete masses. Scanning can also identify cirrhotic livers by demonstrating characteristic patterns of uptake of the label.

Endoscopic retrograde choledochopancreatography (ERCP)

1.ERCP can also be used to visualize stones in the common bile duct.

2.Once located, many stones can be removed via the endoscope, avoiding the need for abdominal surgery.

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