الفهرس 
Anatomy of the biliary systemOnly 14 pages are availabe for public view
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Abstract
Malignant hepatic tumors including primary hepatic cancers & metastases are considered among the most common tumors in the world. Perfect detection is very necessary to ensure accurate staging, to prevent tumors from being falsely diagnosed as inoperable and patients with inoperable tumors from being planned for surgical procedures.
Intrahepatic cholangiocarcinoma represents 5–30% of all primary hepatic malignant tumors, and considered the second most common primary malignant tumor of the liver subsequent to hepatocellular carcinoma (HCC)
In comparison with MRI, CE-CT has a restricted ability to evaluate the spread of bile ducts tumors. MRI is the most useful at this task . This is due to its superior ability for soft tissue contrast and so that it is represented as the imaging modality of choice for cholangiocarcinoma diagnosis and staging . Its accuracy is similar to combined CE-CT and direct cholangiography.
An excellent MRI protocol for cholangiocarcinoma assessment should include MRCP, conventional T1- and T2- weighted abdominal MRI pulse sequences including T1 in- and out-of-phase imaging, diffusion weighted imaging (DWI), and triphasic contrast-enhanced sequences represented in the arterial, portal venous, and delayed phases.
Advantages DW MRI over other imaging modalities in diagnosis of hepatic tumors because it is accurate, no radiationexposure & no utlization of nephrotoxic contrast agents, it can be obtained during a single breath-hold,provides unique information that reflects tissue cellularity and organization , so it seems logical to expect that the use of DW images of the liver will become very common, & may replace routine multiphasic post contrast imaging approaches.
The ADC can provide quantitative measurements of tissue water diffusion, which not used only for disease evaluation, however it is used also for the evaluation of disease responsibilty to treatment.
In our study, 50 patients of finally diagnosed cholangiocarcinoma are evaluated by MRI& DWI were classified into inrahepatic & extrahepatic types which are further subclassified to mass forming, intraductal & strictures types.
According to our study the intrahepatic cholangiocarcinoma (60%) of cases was more common than the extrahepatic types(40%) of the cases as well as the mass forming cholangiocarcinoma is the most common subtype (38 cases ).
Our study illustrated the value of dynamic images as well as DWI in diagnosis of the mass forming& intraductal subtypes of cholangiocarcinoma, however had a limited role in evaluating the stricture type of cholangiocarcinoma which showed no any pattern of enhancement or restricted diffusion.
In our study we found that no significant difference in ADC value between the intrahepatic & extrhepatic cholangiocarcinoma. We also concluded that the ADC value of cholangiocarcinoma lies between the ADC of liver & the ADC of the spleen which are used as a reference for ADC calculation.
SUMMARY AND CONCLUSION
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We also concluded that the sensitivity of DWI is more sensitive than MRCP in diagnosing the mass forming cholangiocarcinoma.
In our study we concluded that diffusion-weighted MRI sequence with