Abstract
Intraductal ultrasonography, which employs a thin, high-frequency ultrasonic probe inserted into the bile duct, produces high-quality cross-sectional images of the bile duct. lntraductalultrasonography is useful in assessing biliary tumor staging including tumor depth infiltration, pancreatic parenchymal invasion, portal vein invasion, and right hepatic artery invasion.However, it has limitations in assessing lymph nodes metastases. The assessment of longitudinal cancer extension along the bile duct is a promising aspect of this area. However, thickening of the bile duct wall is a nonspecific finding that may represent either inflammatory changes that may result from mechanical irritation by a biliary drainage catheter or other factors, or the longitudinal extension of the cancer. ln distinguishing between benign and malignant diseases, a presence of sessile tumor, tumor size greater than 10.0 mm, and interrupted wallstructure on IDUS images were factors that predict malignancy.
