New technique using intraductal ultrasonography for the diagnosis of bile duct cancer.

We investigated the extent to which BDca can be visualized and diagnosed via a percutaneous fistula using IDUS. IDUS was performed in 42 cases, including 15 of normal bile ducts; 12 of choledocholithiasis, and 15 of BDca. The depth of invasion of the BDca was diagnosed with a 93% accuracy rate by visualizing the EP or MA or both. The infiltration of BDca into the surrounding organs was clearly visualized and diagnosed with an accuracy of 100% in the RHA, 93% in the PV, and 93% in the pancreas. These accuracy rates were higher than those obtained by computed tomography or angiography. We believe, therefore, that IDUS should be further studied as a diagnostic modality for staging malignancy in the biliary field.