MRCP

Description

MRCP (Magnetic Resonance Cholangiopancreatography) is a diagnostic MRI procedure used to image the hepato-biliary system and its associated bile ducts. It is typically performed as an outpatient procedure and used to diagnose a wide variety of conditions such as gallstones, inflammation, and tumours.

Being an MRI based procedure, MRCP is relatively safe and quick compared to other similar diagnostic procedures such as ERCP and radiographic imaging e.g. X-Rays/CT Scans. Patients can return to normal activities immediately as long as no sedative is used.

Complications are relatively rare; with a strong focus on preventing any direct MRI related complications through a pre-procedure safety questionnaire designed to ensure that the MRCP is safe for the patient. This includes ensuring that no implants or similar devices are present within the patient which may become dislodged and cause severe injury. More minor complications include reactions to the contrast or sedative.

What is it?

MRCP (Magnetic Resonance Cholangiopancreatography) is a type of MRI scan used to visualise the gallbladder, bile ducts, and the pancreatic ducts. MRI scans use strong magnetic fields to produce highly detailed pictures and videos inside the body. The MRCP is a non-invasive procedure that allows the doctors to investigate the cause of any disease in this area and plan any interventions needed to treat the disease. The areas of interest within the MRCP scan include:

1. The liver and its associated bile ducts
2. The bile duct system
3. The gallbladder
4. The pancreas and its associated bile ducts (1).

Bile is formed in the liver which lies in the upper right quadrant of your abdomen. Through a series of small tubes called bile ducts, the bile travels from the liver into the first portion of the small intestine (the duodenum) where it aids in the digestion of fatty foods. Any bile that is not currently being used is stored in the gallbladder. Bile and other associated enzymes are also moved from the pancreas through to the duodenum alongside this duct system. Hence it follows that disease can occur at any point along this interconnected system, most commonly in the form of inflammation or gallstone formation (2).

Why is it done?

MRCP scans are conducted for a number of different reasons; most often to investigate the possibility of biliary or other abdominal disease. Uses of MRCP include:

1. Detecting any gallstones, tumours, or inflammation within the biliary system.
2. Detecting any inflammation in the region:
3. If this occurs in the pancreas it is called pancreatitis. If the doctor suspects pancreatitis, additional medication (Secretin) may be given around the time of the procedure to help visualise any scarring in the pancreas, the pancreatic biliary system, and to establish how much of the pancreas is functional. This procedure is known as Secretin Enhanced MRCP (3).
4. If this occurs in the bile ducts themselves this is known as cholangitis. This can often manifest as blockages and cysts within the ducts which can be seen on MRCP.
5. If this occurs in the gallbladder it is known as cholecystitis
6. Investigating the cause of any unexplained abdominal pain (4).

MRCP is a purely diagnostic procedure, and hence it does not provide any opportunities to treat the underlying condition. Based on the findings of the MRCP, treatment in the form of surgery or ERCP procedures can be conducted.

Anesthesia

Because MRCP is a pain free and non-invasive scan as opposed to an ERCP which is an actual intervention, no anesthesia or painkillers are required for the procedure. If you do experience claustrophobia, there is the possibility of giving a sedative to help you relax while in the MRI scanner; hence you should speak to a member of the team or your GP well before the procedure if you require this (8). If you are administered a sedative, it is recommended that you avoid driving and heavy lifting for 24 hours after administration, hence you will need to arrange for a friend/family member to pick you up from the hospital.

Will I need to do any preparation

When given your MRCP appointment, you will be sent a safety questionnaire that is required to be filled out before the procedure can take place. Since MRCP uses strong magnetic fields, it is imperative to fill out this safety questionnaire as accurately as possible, taking special care to include any metal prosthesis or replacements inside the body. People with certain implants or prostheses will not be able to undergo the MRCP procedure as these can be dislodged and result in injury. These include:

1. Internal defibrillator or cardiac pacemaker
2. Cochlear Implants
3. Internal surgical clips or staples
4. Implanted artificial heart valves
5. Artificial limbs or metallic joints (9).

If you have had any of the above procedures conducted in the past, either one of the following options will be available to you:

1. The doctor will recommend you to have X-Ray scans to check if any surgical clips/staples still remain in your body. If they do not, then the doctor may decide that the MRCP can go ahead.
2. If the implant is permanent, the doctor may recommend you to have an alternative procedure such as a CT scan or ERCP.
3. The MRCP may get postponed till the equipment either dissolves (surgical staples) or is removed.

It is also recommended that you do not have anything to eat or drink within 4 hours of the MRCP scan, as this will allow the doctors to get the most accurate images and diagnosis.

The Procedure

On arriving at the hospital, you will be checked in and a member of the team will go through the completed safety questionnaire with you to ensure that it is safe for you to have the MRCP scan. You will be given a gown to wear and you will be required to remove all metal jewellery and piercings for your own safety. You may also be given contrast in the form of an injection to help the doctors visualise and image the hepato-biliary system more easily. This injection is usually administered through an injection via a vein in the arm.

The MRI scanner is a long, cylinder piece of equipment that you enter while lying down, head first. The bed is motorised and hence you will be moved automatically into the MRI scanner, which is lined with a large magnet. Pads and head rests are fixed to help you be as comfortable as possible. It is imperative you lie as still as possible during the procedure to ensure that the most accurate pictures are taken. You may begin to feel warm and experience a tingly sensation in your extremities; however should you experience any discomfort, you can press the emergency buzzer that will be provided to you before you enter the MRI scanner which can be used to stop the procedure. The medical team will be watching and monitoring you in a separate room; and you will be able to communicate back and forth with the medical team using a microphone system if you have any concerns. If you prefer, a friend/family member can stay with you while doing the scan, although they may be required to wear protective equipment and remove any metallic objects (10).

A device will be placed on your upper abdomen, which will be used to monitor data during the procedure and receive the radio waves from the MRI scanner. The MRI scanner will provide audio instructions relating to your breathing; hence you will be asked to hold your breath for a short period at certain times. The MRI scanner can be noisy and hence you will be given some headphones to protect your ears and through which you can listen to music or the radio while the procedure is being conducted.

The whole procedure can take between 15-40 minutes depending on the quantity and quality of information needed and whether more detailed scans need to be taken (11).

Post-Procedure

MRCP are usually carried out as an outpatient procedure, and hence you will not need to stay in hospital overnight and can return to your normal activities immediately after the procedure as no recovery is required provided you were not administered with a sedative. A specialist radiologist will study the images and send the reports back to your doctor, which may take anywhere between 1-2 weeks.

Caring for yourself at home

As there are no side effects from the MRCP procedure, you can resume normal activities immediately. However, if you have been given a sedative, somebody will be required to stay with you for 24 hours to help you if you are unable to move about the house.

Where can I find more information

NHS information on MRI scans - https://www.nhs.uk/conditions/mri-scan/