ERCP - Anatomy, Procedure and the role of the Radiographer

What does ERCP stand for?

Endoscopic Retrograde Cholangiopancreatography

What is an ERCP?

A technique utilizing endoscopy and fluoroscopy to diagnose and treat certain problems of the biliary or pancreatic ductal system.

When is an ERCP performed?

When the patient’s bile or pancreatic ducts may be narrowed or blocked due to:

• Gallstones, pancreatic stones, tumour or scar tissue
•  Inflammation due to trauma or illness (such as pancreatitis)
• Sphincters not opening properly

Who is involved in an ERCP?

• The gastroenterologist (doctor performing the procedure)
• A scrub nurse (who remains "sterile" for the procedure)
• A scout nurse (who finds and prepares necessary equipment)
• An anaesthetist 
• A radiographer

Review of Relevant Anatomy

ERCP Anatomy

Specific Vessels related to ERCP

Procedure

•  The patient is places in a LAO position under conscious sedation
•  The doctor will feed the endoscope into the mouth, down the oesophagus, through the stomach until the duodenum and ampulla is visualized
•  The ampulla is dilated using a catheter and guidewire
•  Fluoroscopy is now used to assist in proper placement of the guidewire (i.e. to ensure the guidewire has gone into the CBD not the pancreatic or common hepatic duct)
•  Contrast is injected to visualize the ducts and determine if there are any stones, strictures or other abnormalities
•  The CBD is often dilated using a small balloon, which is filled with air and dragged along the duct and out through the ampulla. This can also be used to remove stones or other material blocking the duct
•  Sometimes, a small cut is made in the ampulla (known as a sphincterotomy) to allow for better drainage of the duct and stone removal
•  Frequently, a stent is also inserted to improve drainage post procedure

Your Role as the Radiographer

• Depending on your department's equipment, you may have to stand in the room to x-ray or you may be able to stay out in the control panel. In the latter, it is important to pay close attention so as not to miss your cue to x-ray.
• Generally the doctor will ask you to x-ray when it is required. As a general rule, if they don't ask you stop, stop screening when they stop looking at the x-ray screen.
• Once you have found your initial position, it is unlikely you will have to move. This initial position is simply being centred over the common bile duct. It is difficult to know exactly where that is until contrast has been injected, but as a guide, have the tip of the endoscope at the bottom, centre of your screen. 
• The middle of the spine should be on the right edge of the screen. Depending on the size of your image plate/receptor, this should allow the entire duct to be visualised. 
• If the detector is quite large, you may be able to centre a little higher and cone down.  
• The doctor may also ask you to magnify the image as required.

Ideal Positioning for ERCP

Generally speaking, when contrast is being injected, you will be needed to x-ray, so pay attention to what is going on around you (e.g. has contrast been asked for?) so you are prepared to screen when required. The doctor will usually ask you to save/take a picture when the duct is full of contrast or when pathology (such as a stone) has been visualised. 

What preparation should you do before an exam?

Doctors are always a lot more pleasant to work with when everything goes smoothly. This frequently will have nothing to do with you, but there are a few simple tips you can do to help:

• Have the patient ID details ready before the procedure begins so you are ready to x-ray straight away
• If you use cassettes, have as many clean cassettes ready as possible and have them as close as possible so they can be changed quickly as multiple quick images are often desirable
• Change any imaging settings (e.g. horizontal or vertical flip, magnification) so the image is correct from the first point of screening
• Where possible, stand in a position out of the way of the doctor/nurses as they often move around a lot
• Ensure everyone in the room is wearing a lead gown - including the patient if they are young
• Bring the detector as close to the patient as possible to decrease magnification and reduce scatter
• Pay attention!! Try to anticipate when you will need to screen. Doctors don't like to ask twice!!