From the Guidelines
Magnetic Resonance Cholangiopancreatography (MRCP) should be performed using a heavily T2-weighted fluid-sensitive 3-D sequence, acquired over 3 to 5 minutes in the coronal plane using respiratory triggering or diaphragmatic gating, to visualize the biliary and pancreatic ducts without invasive procedures. This technique is particularly valuable for diagnosing conditions such as bile duct stones, strictures, tumors, and pancreatic duct abnormalities without radiation exposure or invasive procedures like ERCP 1.
To undergo an MRCP, patients should fast for 4-6 hours before the examination to reduce intestinal motility and gallbladder contraction. Upon arrival at the imaging center, patients change into a hospital gown and remove all metal objects. During the procedure, patients lie on their back on the MRI table, which moves into the scanner. The scan typically takes 15-30 minutes, during which patients must remain still. Sometimes, contrast agents like gadolinium may be administered intravenously to enhance image quality. Patients may be asked to hold their breath briefly during certain sequences to minimize motion artifacts.
The advantages of MRCP include its non-invasive nature, lack of radiation use, and lower cost, in addition to the potential to add MR elastography (MRE) for further information on disease staging and prognosis 1. However, limitations of MRCP include poor visualization of peripheral intrahepatic branches, which limits the ability to diagnose very early intrahepatic PSC, and false-positive findings in cirrhosis of any etiology due to tapering and duct distortion.
Key points to consider when performing MRCP include:
- Using a high-quality MRI evaluation to provide information on bile duct thickness and enhancement, the status of hepatic parenchyma, and complications of liver disease including evidence of portal hypertension 1
- Performing a complete, high-quality MRI evaluation to diagnose PSC, which has a pooled sensitivity and specificity of 86% and 94%, respectively 1
- Considering the use of MRCP in patients with suspected sclerosing cholangitis or biliary stricture, as it is the preferred imaging modality, avoiding the possibility of suppurative cholangitis that may be induced by endoscopic catheter manipulation of an obstructed biliary system 1
From the Research
Magnetic Resonance Cholangiopancreatography (MRCP) Procedure
To perform MRCP, the following steps can be taken:
- Use MR imaging to visualize fluid in the biliary and pancreatic ducts as high signal intensity on T2-weighted sequences 2, 3
- Utilize heavily T2-weighted RARE and HASTE sequences for the morphologic evaluation of intra- and extrahepatic bile ducts 4
- Consider using contrast-enhanced magnetic resonance cholangiography (CE-MRC) with hepatocyte-selective contrast agents for a noninvasive functional evaluation of the hepatobiliary system 4
- Avoid using T2-weighted MRCP sequences after administration of Gd-EOB-DTPA, as this contrast agent decreases signal intensity of the biliary structure on these images 5
- Use the short-echo time (TE) Cube sequence for MRCP at 3 T, which has been shown to have better image quality and visibility of biliary structures compared to conventional 3D-FSE MRCP 6
MRCP Techniques
Some techniques that can be used in MRCP include:
- T2-weighted sequences to visualize fluid in the biliary and pancreatic ducts 2, 3
- Heavily T2-weighted RARE and HASTE sequences for morphologic evaluation of intra- and extrahepatic bile ducts 4
- Contrast-enhanced magnetic resonance cholangiography (CE-MRC) with hepatocyte-selective contrast agents 4
- Short-echo time (TE) Cube sequence for MRCP at 3 T 6
Clinical Applications of MRCP
MRCP has been shown to be useful in a variety of pancreatic and biliary disorders, including: