MRCP Flashcards
What does MRCP mean?
Magnetic Resonance CholangioPancreatography
Why do we do MCRP?
MRCP can be used to evaluate various conditions of pancreas and biliary ductal system, some of them are:
identification of congenital anomalies of the cystic and hepatic ducts
post-surgical biliary anatomy and complications
pancreas divisum
biliary stones
biliary strictures
chronic pancreatitis
trauma to biliary system
What is ERCP?
Endoscopic retrograde cholangiopancreatography, or ERCP, is a procedure to diagnose and treat problems in the liver, gallbladder, bile ducts, and pancreas. It combines X-ray and the use of an endoscope—a long, flexible, lighted tube.
Why do MRCP rather than ERCP?
MRCP demonstrates the anatomy and patency of the biliary tree. It does not allow treatment during the procedure, but:
MRCP is non-invasive
Complications of ERCP include
Pancreatitis
Duodenal perforation
Demonstrates anatomy and pathology of surrounding organs and structures
Appointment time usually 20-30 minutes
Suitable patients may have MRCP followed by therapeutic ERCP
Patient prep for MCRP?
Nil by mouth for 4 hours (no eating or drinking)
Glass of pineapple juice just prior to examination
Why do you eat nothing before MCRP, for patient prep?
Fluid is very hyperintense on the MRCP sequence
All structures containing fluid will therefore show up brightly
If the stomach and duodenum are filled with food and drink the signal returned from these structures will mask that of the biliary tree and reduce the diagnostic potential
Why drink pineapple juice before MCRP?
Negative oral contrast to ‘null’ the duodenum during MRCP:
Pineapple juice is rich in manganese and shortens T2 relaxation time
The test image demonstrates the T2 signal intensity of pineapple juice when compared to water and orange juice.
How do you avoid Motion artefact caused by respiratory motion during MCRP
Patient can be fitted with bellows during positioning so that the scans may be gated with respiratory movement
Some of the sequences may be so short that the patient can be asked to hold their breath for the duration of image acquisition
The scanner may have software to provide respiratory gating without the use of bellows
What is Secretin stimulated MRCP?
sMRI is used mainly to assess for pancreatic duct pathology
Secretin is a hormone that stimulates production of pancreatic fluid and relaxes the sphincter of Oddi
Imaging is performed repeatedly for up to 9 minutes post-injection of secretin.
The pancreatic duct is most dilated at 2-3 minutes.
The duodenum is best visualised at 8-9 minutes.
The MRCP images are often viewed as a Maximum Intensity Projection (MIP), what does this mean and what is good and bad about it?
3d volume is collapsed into a planar image – the highest attenuation focus creates the final attenuation on the images.
Can portray vessel calibre or stenosis inaccurately due to superimposition of high attenuation foci such as calcification.
Useful when vessels are very small and curved
hyperintense meaning?
appears brighter; higher signal
isointense meaning?
appears of equal brightness
hypointense meaning?
appears darker; lower signal
