The test will show whether your symptoms are caused by gallstones. More than four out of five bile duct cancers will be clearly seen by this method. It will also show whether the cancer has spread to other nearby parts of the body.

You lie on your back on a couch. When you are comfortable, a gel will be spread on your abdomen to help the sound waves transmit through your skin.

A device like a microphone is pressed onto your abdomen. Sound waves from it bounce off the internal organs, and echo back to make pictures on a computer screen.

This is not painful, but if you are already tender, there may be some discomfort when the doctor or radiographer presses firmly to get a good picture. It takes between 15-45 minutes to do.

There are no known side-effects.

The ultrasound scan will be done during a day visit to the radiology (X-ray) department at your local hospital.