Auxiliary examination methods for bile duct cancer

At present, the medical community has not yet clearly concluded the cause of bile duct cancer, so bile duct cancer must be supplemented with some examination items to be diagnosed. Although some related factors have been found, such as pancreatic juice reflux, bile stasis, tumor-like differentiation of liver stem cells, etc., which may induce bile duct cancer; some related symptoms, such as abdominal discomfort, nausea, etc., but this still cannot confirm that it is bile duct cancer, so today we will learn about the auxiliary examinations for bile duct cancer.

1. Laboratory examination: The main manifestations are abnormal liver function of obstructive jaundice, such as increased bilirubin and alkaline phosphatase.

2. Ultrasound examination: Repeated and careful ultrasound examinations can show dilated bile ducts, obstructed sites, and even tumors. The ultrasound images of bile duct cancer can be mass-like, cord-like, protruding, and thrombus-like. Intrahepatic bile duct cancer often presents as a mass or cord-like, hilar cancer often presents as a cord-like, and lower bile duct cancer often presents as a protruding type. Thrombotic images of the hilar region may be hilar cancer, gallbladder cancer, or metastatic cancer. Since bile duct dilatation occurs before jaundice, ultrasound has the value of diagnosing early bile duct cancer.

3. CT: CT is still a conventional examination method. The basic manifestation of cholangiocarcinoma is that the proximal bile duct of cholangiocarcinoma is obviously dilated. The bile duct wall close to the tumor is thickened. The bile duct is clearer and can be enhanced during enhanced scanning. The lumen is unplanned and narrowed. It provides a basis for the staging of the lesion and the possibility of surgical resection. CT scanning can achieve the same effect as B-ultrasound, and the image is clearer.

4. PTC: Percutaneous transhepatic cholangiography is the basic means of diagnosing bile duct tumors and the main method of diagnosing bile duct cancer. PTC examination can be performed on patients with intrahepatic bile duct dilatation shown by B-ultrasound and CT examination. This examination is of great significance for determining the surgical plan before surgery, and its correct diagnosis rate can reach more than 90%. However, this examination is traumatic and can easily cause bile leakage and cholangitis. To avoid the above complications, it is best to perform the examination one day before surgery, try to drain the contrast agent as much as possible after the examination, and be ready for surgery at any time.

5. EUS: Endoscopic ultrasound is a new diagnostic tool that combines two imaging technologies, endoscopy and intracavitary ultrasound. The bile duct wall can be divided into three layers under EUS: the first layer is high-echo equivalent to mucosa plus interface echo; the second layer is low-echo smooth muscle fiber and fibroelastic tissue; the third layer is high-echo loose connective tissue plus interface echo. The detection rate of cholangiocarcinoma is 96% when it appears as a low-echo or high-echo mass under EUS, and it can indicate the size of the tumor and the presence of lymph node metastasis.

6. ERCP: Retrograde pancreaticocholangiopancreatography is suitable for cases where the bile duct is not completely blocked. It can show the obstruction site and determine the range of the lesion from the distal end of the bile duct. Biliary drainage (ENBD/ERBD) can also be performed after surgery. The combined use of PTC and ERCP can significantly improve the diagnosis rate of bile duct cancer. The drained bile can also be tested for tumor markers and cytology. ERCP alone can only show the situation in the middle and lower parts of the common bile duct, but combined with PTC, it helps to clarify the site of the lesion, the upper and lower boundaries of the lesion, and the nature of the lesion. It is especially suitable for those with incomplete bile duct obstruction accompanied by coagulation disorder. After ERCP examination, the diagnostic compliance rate is less than 7.5%.

7. SCAG: Angiography generally cannot diagnose the nature and extent of the tumor, but it can mainly show whether the blood vessels at the liver portal are invaded. If the proper hepatic artery and portal vein are invaded, it means that the tumor has extended outside the liver and it is difficult to perform a radical resection. This examination helps to estimate the resectability of the tumor before surgery.

8. MRCP: Magnetic resonance cholangiopancreatography can simultaneously display the bile ducts proximal and distal to the obstruction, thus being able to calculate the length of the obstruction and the distance from the ampulla, facilitating the formulation of surgical plans.

9. Fiber choledochoscope can clearly identify the location and range of lesions, and is especially suitable for early stage tumors of intrahepatic bile duct and duodenal pancreatic bile duct. Fiber choledochoscope can not only show the morphology of lesions, but also perform biopsy to confirm the diagnosis. Peroral choledochoscope (PCS) and fiber choledochoscope can directly visualize lesions in the bile duct and take tissue biopsy or cell brushing.