August 14, 2023
Primary liver cancer (HCC) is one of the top ten malignant tumors announced by the World Health Organization, with approximately 1 million people diagnosed each year. Among all malignant tumors, the incidence rate of primary liver malignant tumors in China is the third in men and the seventh in women. Primary liver cancer can generally be divided into three categories based on histological classification: hepatocellular carcinoma, cholangiocarcinoma, and mixed type carcinoma, with the most common being hepatocellular carcinoma. The pathological classification of liver cancer includes diffuse, nodular, and massive types. The main clinical symptoms include right upper abdominal pain, bloating, poor appetite, fatigue and weight loss, fever, and abdominal masses.
1. Ultrasound diagnosis of primary liver cancer
Ultrasound examination is currently the most commonly used and effective imaging diagnostic method for liver cancer. Its value lies in: ① identifying intrahepatic space occupying lesions, which can detect small liver cancer nodules with a diameter of 1cm; ② Indicating the nature of liver occupying lesions, especially the differentiation of cystic, solid, and hemangioma from liver cancer; ③ Clarify the exact location of liver cancer in the liver and its relationship with important structures to guide the selection of surgery and other treatment methods; ④ Understand the spread and metastasis of liver cancer, including satellite nodules and tumor thrombi in the portal vein; ⑤ Ultrasound guided liver puncture or local tumor injection treatment; ⑥ Liver cancer screening and combined with laboratory tests to improve the detection rate of small liver cancer.
2. Ultrasound manifestations of primary liver cancer
The sonographic manifestations of primary liver cancer mainly include the following aspects In the early stage, the volume of the lesion is small, and there is no significant change in the size and morphology of the liver. As the volume of the tumor increases, the liver volume can be localized and the contour is irregular. Diffuse hepatocellular carcinoma often has no significant changes in liver morphology, and sometimes its contour can be irregular The internal echoes vary in height and exhibit variability, with high echoes, low echoes, mixed echoes, and isoechoes all appearing. The capsule of liver cancer nodules smaller than 3cm can be seen as complete or incomplete. When the volume of liver cancer is large, the capsule is generally blurry, and some nodules with a diameter greater than 5cm still have intact capsules. At this time, the inner side of the nodules is often accompanied by sound halos Often accompanied by the background of liver cirrhosis ultrasound, the regenerative nodules in liver cirrhosis are mostly hyperechoic and have no capsule. Diffuse liver cancer is characterized by diffuse nodular echoes throughout the entire liver, mostly low echogenicity, with a diameter of several millimeters to 1cm. Tumor thrombi are often visible in the portal vein, while cirrhosis does not Scattered nodular hypoechogenicity can be seen around the larger primary lesion, with a diameter of 0.5~1.5cm. It is called a "satellite nodule" and is often a sign of intraparenchymal metastasis of liver cancer. ⑤ Lesions located in the hilar region can compress the bile ducts, causing the intrahepatic bile ducts above the compressed area to expand; When the compression site of the lesion is below the level of the cystic duct, the gallbladder, common hepatic duct, and their intrahepatic branches all expand. ⑥ Cancer thrombi can appear in the portal vein system, hepatic vein system, and inferior vena cava. The ultrasound manifestation is an increase in the inner diameter of the aforementioned blood vessels, with solid echoes detected within the lumen. Depending on the time of tumor thrombus occurrence, it can be low echo, isoechoic, or hyperechoic, or it can also appear as foggy echoes. If the tumor thrombus fills the lumen, the blood flow signal in the blood vessels disappears. ⑦ CDFI: High speed and high resistance arterial blood flow signals can be detected within the lesion, with literature reporting a maximum flow rate of 70-90cm/s and a RI (blood flow resistance index)>0.65. When the tumor volume is large, the surrounding blood flow formed by the pushing of the portal vein or hepatic vein can be seen around it. ⑧ Lymph node metastasis can be seen in the hilar area, around the abdominal aorta, inferior vena cava, and around the pancreas, with circular or elliptical hypoechoic lesions, single or multiple Color Doppler Energy Imaging (CDEI): Showing varying thickness and tortuosity of blood vessels within the tumor.
