Biliary Obstruction Essay

Evaluation of biliary obstruction for its nature is common clinical problem. (Frances Tse) There are many imaging modalities used to investigate in patient with suspected biliary abnormality such as transabdominal ultrasound, endoscopic ultrasound (EUS), ERCP, CT, MRI or percutaneous transhepatic cholangiography (PTC). MRI has now been increasing use and can reduce the requirement of ERCP or PTC due to its accuracy for evaluation of most biliary condition. (O’Connor) Magnetic resonance imaging has now been increasingly used in a wide variety of clinical application. Magnetic resonance imaging has developed new techniques for evaluation of biliary tract such as magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted imaging (DWI). (Stroszczynski, Blechacz&Gore, Adamek, Suthar)
Study shows that MRCP has high sensitivity and specificity in terms of identifying presence and level of obstruction but is less helpful when it comes to differentiating
the cause of obstruction. (Romagnuolo, Yeh Benjamin M)
Dynamic contrast-enhanced MRI in combined with MRCP has proven to gives information the causes of obstruction. (Bilgin)
For DWI, many studies find it helpful in addition to MRCP for differentiating the nature of biliary obstruction.
(Rania A. Maarouf, Yoo, Cui) But no added value of DWI to conventional contrast-enhanced MRI/MRCP is observed. (Yoo,
Choi)
Gadolinium-based contrast agents (GBCA) is intravenous drugs used in MRI.
It is very helpful agent but also have its adverse effect, some is rare but can be fatal and without treatment (nephrogenic systemic fibrosis aka NSF) especially in patient with poor renal function. (FDA Drug Safety Communication: New warnings for using gadolinium-based contrast agents in patients with kidney dysfunction 12/2010) Additional contrast agent means increased cost of imaging modality. And also there are research showing possible deposition of Gadolinium-based contrast agent in dentate nucleus and globus pallidus in patient who underwent previous MRI with Gadolinium-based contrast administration. (Kanda) So consideration the use of Gadolinium-based contrast agent should not be lightly
taken. Our hospital is tertiary center hospital in northeastern Thailand, the highest endemic area of cholangiocarcinoma. (Sripa, Shin) Patients which cholangiocarcinoma in this area usually present with clinical manifestation of biliary tract obstruction. So early detection and differentiation of nature of biliary obstruction in our area means increased chance of curative treatment. (Mairiang, Denes) From our experience, some cholangiocarcinoma patients who underwent MRI protocol for eva/luation of biliary obstruction do not receive Gadolinium-based contrast agent due to poor renal function. Skeptical of accuracy in differentiating the causes of biliary obstruction is inevitable without presence of dynamic contrast-enhance MRI sequences.
Thus, the purpose of this study was to compare the diagnostic accuracy between combined MRCP with DWI images and combined MRCP with contrast-enhanced MRI images for differentiation of malignant and benign biliary obstruction.