N CTCP can accurately define the obstructive site in lower bile duct obstructive diseases,and its specificity for the diagnosis of choledocholithiasis and malignant biliary obstruction is very high.

• N CTCP对低位胆管梗阻性疾病定位准确 ,对胆管结石及恶性胆管梗阻判断有较高准确性。