Researching the diagnostic significance of Biliary Tract Neoplasm under combining DWI sequence with MRCP versus MRCP only separately.

The purpose of the study is to evaluate the usefulness of diffusion weighted imaging(DWI) combined with MRCP of 3.0T magnetic resonance imaging (MRI) in the evaluation of suspected malignant bile duct diseases. People with suspected Biliary Tract Neoplasm based on clinical symptoms (such as jaundice and thinness with unknown reasons) and CA-199 value raises are included.Diagnosis divided into two steps: the first one，only provide conventional MR sequences and MRCP images to make a diagnosis; the second step,provide the DWI images additionally, combining the image data before to make a diagnosis. Hypothesis is that DWI sequence should be regularly added into MRCP examination for improving diagnosis rate of Biliary Tract Neoplasm.

Inclusion Criteria:

• Informed consent
• Suspected Biliary Tract Neoplasm based on clinical symptoms(such as jaundice and thinness with unknown reasons)and CA-199 raises（>37U/mL）
• No evidence of clinical symptoms or CA-199 increase by non-bile duct cancerous factors(hepatitis,cholangeitis,stones)
• Age ≥ 16

Exclusion Criteria:

• Previous Biliary Tract Neoplasm surgery
• Contraindication for MRI (such as pacemaker or inner ear implant)
• Claustrophobia
• Age < 16

Two experienced professors of radiology observed and analyzed the images separately. They were not involved in image acquisition and were blinded to the patients' clinical, surgical and histological information. Conventional MR sequences were qualitatively analyzed in the first reading session, including T2WI, FIESTA, 2D MRCP and 3D MRCP sequences, and after one week, DWI under three different b values with ADC map combined with the preceding conventional sequences were analyzed respectively as the second reading session.