Question
Which among the following are true about the diagnostic technique shown in the picture below ?
A. MRI is used to obtain the image.
B. CT is used for the images.
C. It shows the biliary tree.
D. a and c.
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Correct Answer » D Explanation |
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The diagnostic technique shown in the picture above represents MRCP.
Magnetic resonance cholangio pancreatography (MRCP)
It is a non – invasive alternative to evaluate biliary tree. The ‘high signal bright bile technique’ is preferred & performed using either CE- FAST (contrast enhanced Fourier aquired steady state) or FSE (fast spin echo) pulse sequences in coronal plane without intravenous contrast agent.
CE-FAST is a variant of gradient echo imaging & utilize T2- w breath hold sequences. It is more accurate in demonstrating choledocholithiasis. Whereas, FSE is spin echo imaging and more accurate in imaging cause of obstruction in malignant biliary or pancreatic disease.
MRCP can visualize common bile duct, common hepatic duct, & main right and left ducts. It has replaced PTC (percutaneous transhepatic cholangiography) & ERCP in significant proportion. Since conventional MRCP does not rely on contrast excretion, it is suitable for jaundiced patient, a major advantage over CT- intravenous cholangiography (CT – IVC).
Contrast enhanced MRCP uses hepatobilary contrast eg. Mangafodipir trisodium, gadobenate dimeglumine & gadoxetic acid disodium. Images are taken 30 min after IV infusion to allow hepatocyte uptake and biliary excretion, therefore depends on near normal hepatocyte function (as with CT – IVC) and uses T1 weighted images (allowing more manipulation).
It is used for liver donor transplant workup, assessments of bile leak & biliary communication with cysts, detecting segmental obstruction. However, it is not as sensitive as MRCP for detecting choledocholithiasis.
