Role of MRCP in Differentiation of Benign and Malignant Causes of Biliary Obstruction

Abstract

Background: Differentiation of the benign and malignant etiology of biliary obstruction is difficult. We studied the diagnostic accuracy of MRCP (Magnetic Resonance Cholangio-pancreatography) in differentiating between benign and malignant causes of biliary obstruction.

Aim: To evaluate the role of Magnetic Resonance Cholangio-Pancreatography in differentiating benign from malignant causes of biliary obstruction using surgical, ERCP or histopathological findings as gold standard.

Materials and methods: Seventy five patients with clinical and laboratory finding suggestive of biliary obstruction underwent MRI/MRCP. The final diagnosis was based on either surgical findings, histopathology of resected specimen or ERCP findings. Diagnostic effectivity of MRCP was calculated which included sensitivity, specificity and accuracy. Statistical analysis was done by using chi-square test and p value was calculated.

Results: Out of 75 cases, there were 54 benign and 21 malignant cases. Mean age of patients with malignant obstruction was more than benign with slight male preponderance. The diagnostic accuracy of MRCP in differentiating benign from malignant biliary obstructive diseases in correlation with surgical, ERCP and histopathological outcome was 93.3%, sensitivity 85.7%, specificity 96.3%. It was found that irregular, asymmetric and long segment narrowing was more common in malignant stricture.

Conclusions: MRCP is the investigation of choice for suspected choledocholithiasis, choledochal cyst and primary sclerosing cholangitis. A benign stricture can be differentiated from a malignant one if it shows regular, symmetric and short segment narrowing. Irregular, asymmetric and long segment narrowing was more commonly found in malignant stricture.

Keywords: Biliary obstruction; Cholangiocarcinoma; Choledocholithiasis.

[Table/Fig-3]:

Choledocholithiasis with Cholelithiasis (a) MRCP image shows multiple well defined filling defects (arrow), suggestive of multiple calculi, in the lumen of CBD and gall bladder (b) T2W axial image shows filling defect suggestive of calculus in distal CBD

[Table/Fig-5]:

Cholangiocarcinoma (a) MRCP shows dilated IHBR in both lobes of liver with narrowing at hilum proximal and mid CBD is not visulaised. Distal CBD is normal in caliber. (b) Long segment and irregular thickening of CBD is seen on T2W coronal image suggesting malignant pathology

[Table/Fig-8]:

Post Cholecystectomy Stricture: MRCP image show dilated IHBR with abrupt, short segment narrowing at hilum, mid and distal CBD normal in caliber

[Table/Fig-9]:

CBD Stricture with Pancreatitis (a) dilated IHBR and CBD seen on MRCP image with fluid collection near distal end of CBD. Distal CBD narrows abruptly. (b) T2W axial image shows pseudocyst near head of pancreas and pancreatitis involving body and tail region

[Table/Fig-10]:

Primary Sclerosing Cholangitis: MRCP image shows multiple strictures, irregularities of bile ducts and bile duct wall thickening

[Table/Fig-11]:

Choledochal cyst: MRCP image shows dilated both intra and extrahepatic biliary ducts suggestive of choledochal cyst type IV a