Magnetic resonance cholangiopancreatography (MRCP)

概述

Magnetic resonance cholangiopancreatography (MRCP) is a special type of magnetic resonance imaging (MRI). It makes clear images of the bile ducts, liver, gallbladder and pancreas. Healthcare teams use MRCP as a noninvasive test to check for diseases or conditions that might involve these organs.

MRCP is done using an MRI scanner. It uses a strong magnetic field, radio waves and a computer to make images. It does not use radiation. It may be done with or without the use of contrast material.

The test uses special image settings that highlight fluid in the bile ducts and pancreatic ducts. This lets a radiologist look for stones, blockages, narrowing, inflammation and other changes in these ducts. A radiologist is a doctor who reads imaging tests.

Types

In some situations, a specialized MRCP test called secretin-enhanced MRCP (S-MRCP) may be used.

S-MRCP uses a medicine called secretin. Secretin causes the pancreas to release fluid. This makes the pancreatic ducts easier to see for a short while and lets the radiologist watch how the duct responds. S-MRCP may provide more information than standard MRCP about how the pancreatic ducts look and function.

S-MRCP may be helpful for some pancreatic conditions. These include chronic inflammation of the pancreas, called pancreatitis, or structural issues with the pancreas, such as narrowing of a duct or changes after surgery.

目的

Your healthcare team may request MRCP when it needs a noninvasive, detailed look at your bile ducts, pancreatic ducts or nearby organs. It may be done as part of planning for a more invasive procedure, such as endoscopic retrograde cholangiopancreatography (ERCP) or surgery to remove a tumor.

MRCP can help evaluate several symptoms, including belly pain, a suspected blockage in the ducts, and yellowing of the skin and eyes, called jaundice.

MRCP may be used to look for:

• Pancreatic cysts or changes in the pancreatic duct.
• Gallstones in the gallbladder or in the common bile duct.
• Narrowing or blockage of a bile duct or pancreatic duct.
• Infection or injury of the bile ducts or pancreas.
• Pancreatitis and some of its causes or complications.
• Cancer in the pancreas, bile ducts or nearby structures.
• Differences in how the bile ducts or pancreatic ducts were formed.
• A cause of unexplained belly pain.

How MRCP compares with other imaging tests

Several tests can look at the liver, gallbladder, bile ducts or pancreas. The best test for you depends on what your care team needs to find out. Here is what some other tests are used for:

• An MRI gives detailed pictures of organs and soft tissues. It may be used to look for a tumor.
• A CT scan uses X-rays to quickly show the abdomen. It may be used for belly pain that comes on suddenly, tumors or complications of pancreatitis.
• A hepatobiliary iminodiacetic acid (HIDA) scan uses a small amount of radioactive material to show how bile moves through the liver, bile ducts and gallbladder. It may help check gallbladder function and look for bile leaks or blockages.
• An endoscopic retrograde cholangiopancreatography (ERCP) exam gives images of the bile ducts and pancreatic duct. It can be used to diagnose and treat conditions such as gallstones. But it is more invasive than MRCP. During an ERCP, your team passes a thin, flexible tube called an endoscope through your mouth down to your small intestine. The tube has a tiny camera at the end. Contrast material and radiation also are used.

MRCP and pancreatic cancer

MRCP can help find changes in the pancreatic ducts and tissues that may be signs of pancreatic cancer. It also can be used to plan surgery to remove a tumor.

MRCP alone does not determine whether a person has pancreatic cancer. Solid tumors are evaluated using other MRI images as well. These include contrast-enhanced images that show the tumor and its relationship to nearby blood vessels. CT scans or other tests also may be part of the evaluation.

风险

For most people, magnetic resonance cholangiopancreatography has little risk.

Possible risks include:

• Effect on metal or implanted devices. The strong magnetic field and radio waves of the MRI scanner can affect metal objects in the body and some implanted devices. Your care team checks for these before the exam.
• Contrast reaction. Some MRCP exams use a gadolinium-based contrast material. Contrast is given through a vein to highlight specific features on the MRI images. Allergic reactions are uncommon and typically mild. Newer contrasts that contain gadolinium are generally safe for people with kidney disease. But that might not be the case with older types of contrast. Ask your healthcare team if the type of contrast being used is safe for you.
• Sedation risks. If you need medicine to help you relax, your care team monitors you for concerns related to sedation.
• Risks during pregnancy. Tell your care team if you are or might be pregnant. Available evidence has not shown harm to a fetus from MRI without contrast material. Gadolinium contrast generally is avoided during pregnancy unless its benefits are expected to outweigh the risks.
• Risks related to secretin. Secretin can cause side effects. Mild nausea, belly pain or flushing have been reported, but severe reactions are not common.

如何进行准备

How you prepare depends on the imaging center you go to and the type of MRCP being done. Follow the instructions from your healthcare team closely.

Before the exam, your care team may ask you to follow specific instructions. These are often related to:

• Food and drink. Follow instructions about when to stop eating or drinking. Fasting instructions vary between facilities. Secretin-enhanced MRCP may have special instructions because food and drink in the digestive tract can affect the images.
• Medicine. Tell the care team about medicines you take. Unless your team tells you otherwise, take your regular medicines as usual.
• Allergies and other health conditions. Tell the care team about any allergies, health conditions, kidney disease or recent surgery.
• Pregnancy. Tell the care team if you are pregnant or think you might be pregnant.
• Implanted devices. Tell the MRI technologist about any pacemaker or other implanted medical device, metal fragments, or other metal in your body.

Typically, you are asked to change into a gown and to remove things that might affect the magnetic imaging. These might include:

• Jewelry.
• Hairpins.
• Eyeglasses.
• Watches.
• Wigs.
• Dentures.
• Hearing aids.
• Underwire bras.
• Cosmetics that contain metal particles.

Tell your care team ahead of time if being in a small space makes you anxious. Medicine to help you relax may be an option.

If you receive a sedative, your care team likely will ask you to have someone with you to drive you home.

可能出现的情况

What you can expect with magnetic resonance cholangiopancreatography varies according to where you have it done. Ask your healthcare team for specific information about your exam. Here's an overview of a typical MRCP procedure.

MRI scans in general take about 30 to 60 minutes. Using secretin adds more time.

Before the procedure

A member of the care team reviews MRI safety questions with you. If your exam includes contrast, secretin or another medicine given through a vein, your team places an IV in your forearm or hand.

Some facilities give you an oral contrast drink before MRCP to reduce fluid signals from the stomach and make the ducts easier to see.

During the procedure

You lie on a movable table that slides into the MRI scanner. The scanner uses a strong magnetic field, radio waves and a computer to make the images. A member of your care team monitors you from another room. You can talk with the team member by microphone.

You need to stay as still as you can. The technologist may ask you to hold your breath briefly while some images are taken. Movement and difficulty holding your breath can make the images less clear.

The procedure is painless. You don't feel the magnetic field or radio waves, and there are no moving parts around you. You may hear loud tapping or knocking sounds from the MRI scanner. Wearing earplugs or headphones can help block the noise.

If you are having secretin-enhanced MRCP, secretin is given through an IV. More images are taken as the pancreas releases fluid. Secretin-enhanced imaging adds time to an MRCP exam.

After the procedure

If you did not receive a sedative, you can return to your usual activities and eating habits after an MRI exam.

If you had medicine to help you relax, follow the discharge instructions from your care team. You will need someone to drive you home.

结果

A radiologist reviews the MRCP images and sends a report to the healthcare professional who requested the test. The report also may appear in your electronic health record.

An unusual MRCP result does not mean one specific disease. Depending on the reason for the test, the images may show findings such as:

• A stone in a bile duct.
• A widened, narrowed or blocked bile duct or pancreatic duct.
• Inflammation or changes related to pancreatitis.
• A cyst or mass.
• An unusual connection or arrangement of the ducts.

What happens next depends on your results and why your care team requested the test. Your healthcare team may recommend more testing or another procedure, if needed. For example, your team may request an ERCP to treat certain conditions, such as stones or a blockage in the bile duct. ERCP also can be used to get a tissue sample, called a biopsy, of a tumor. MRCP results may be used to plan treatment for pancreatic cancer.

Ask your care team when and how you will receive your results.