What are the specific examination methods for liver cancer? Introduction to the methods of ultrasound examination for liver cancer

Regarding the method of ultrasound examination, this is a question that many liver cancer patients are concerned about. The following experts will introduce the ultrasound examination method of liver cancer.

1. Encapsulation

Liver cancer nodules with a diameter of <3cm often have a complete capsule. The capsule is composed of fibrous tissue, and its acoustic impedance is higher than that of the surrounding liver tissue and tumor, thus forming an interface reflection. On the two-dimensional sonogram, a thin low-echo membrane can be shown surrounding the entire tumor nodule. The thickness of the capsule is estimated to be <0.5mm. On the sonogram, the capsule is relatively smooth and uniform, with a regular shape, and is round or oval. This reflects the characteristics of the expansive growth of small liver cancer. However, the capsule on the sonogram always appears interrupted on both sides of the nodule, which is the echo loss effect of the large interface. When the liver cancer is very large, its capsule is generally unclear. However, there are also cases where the capsule of the cancer nodule is greater than 5cm in diameter and is still very intact. At this time, the inner echo is often accompanied by an acoustic halo.

2. Internal Echo

The echoes inside cancerous nodules vary in height and tend to be variable. Except for uniform low-echo nodules, the echoes of other cancerous nodules are unevenly distributed. The detection rate of liver cancer nodules <1 cm by ultrasound is 33% to 37%. Cancerous nodules are classified according to the height of the echoes as follows:

1. Hypoechoic nodules

2. Hyperechoic nodules

3. Mixed nodules

4. Echoic nodules

5. Relationship between nodule echogenicity and blood supply

3. Color blood flow of cancer nodules

Liver cancer nodules and their surroundings are rich in blood supply, and various blood flow information can be obtained. Second harmonic acoustic contrast imaging color Doppler ultrasound has a high sensitivity in detecting tissue blood flow and can accurately reflect the blood supply of liver cancer. Color Doppler ultrasound can identify the inflow vessels, outflow vessels and intratumoral vessels of liver cancer nodules. The inflow vessels can be the hepatic artery or the portal vein. The outflow vessels can be the hepatic vein or the portal vein. The intratumoral blood vessels appear as tree-trunk-like, colorful dot-like or color-inlaid "clustered" plaques, which can be hepatic artery, portal vein or hepatic vein blood flow in spectral Doppler analysis. The blood flow around the cancer nodule can appear as a full circle or arc-shaped surround, and spectral Doppler can be used to measure whether it is continuous portal blood flow or pulsating arterial blood flow.

4. Cancer Thrombus

Patients with liver cancer are prone to cancer thrombi, which may appear in the portal vein system, hepatic vein system or biliary system.

1. Tumor thrombus in the hepatic veins Tumor infiltration in the hepatic veins is one of the characteristic lesions of liver cancer, and early lesions are no exception. Tumor thrombus can spread from small hepatic veins to larger veins, or block the outflow tract due to venous tumor thrombus, and spread in reverse to small portal veins, larger portal veins or the main trunk of the portal vein.

2. Portal vein cancer thrombus In pathological observation, almost all patients with hepatic vein cancer thrombus have portal vein involvement. In cases of liver cancer combined with cirrhosis, the cirrhosis leads to retrograde development of cancer thrombus due to obstruction of the output vein. Portal vein cancer thrombus may also occur if the tumor directly invades the portal vein.

3. Cancer in the bile duct system The bile duct system is an outflow duct and a channel for bile excretion. If the tumor breaks off or invades the small hepatic duct, it can flow downstream to form a tumor thrombus in the common hepatic duct or common bile duct. The tumor thrombus in the bile duct can also invade directly from the adjacent liver cancer or the portal vein. The bile duct tumor thrombus is often accompanied by symptoms such as persistent jaundice and obvious pain.

5. Lymph Node Metastasis

1. Ultrasound images of lymph node metastasis in the first hepatic portal area show round or oval hypoechoic foci of 0.5-2 cm in size around the gallbladder neck, common bile duct, and portal vein, single or multiple. Multiple enlarged lymph nodes can cause compression of the common bile duct and jaundice.

2. Second hepatic portal lymph node metastasis: The lymphatic vessels near the head and diaphragm of the liver converge to the peripheral lymph nodes where the three hepatic veins of the inferior vena cava flow into the second hepatic portal. Because of the deep location here, it is often difficult to detect enlarged lymph nodes.

3. Retroperitoneal lymph node metastasis Lymph node metastasis around the abdominal aorta, inferior vena cava and pancreas appears as round or oval hypoechoic foci, single or multiple.

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