Ultrasound examination (ultrasound) of the liver

Ultrasonography is one of the most important imaging modalities for suspected liver disease, used both to prove the presence of a metastatic lesion and to rule out other pathology. It is one of the tools for assessing focal liver lesions. This study is invaluable in the differential diagnosis of jaundice, to identify complications of liver cirrhosis. As a result, ultrasound is an indispensable tool in clinical studies of the hepatobiliary system.

The relevance of the diagnostic method

The relevance of ultrasound examination of the liver is expressed in the fact that this study is the first and most important imaging method for suspected liver disease, as well as a first-line indication method in assessing liver function and cholestasis, for the differential diagnosis of jaundice (diagnosis / exclusion of cholestasis), for monitoring complications of cirrhosis (ascites, portal hypertension), to detect, exclude and monitor the tumor. Supplementing ultrasound with contrast agents enhances imaging, especially for tumor detection and characterization.

Sonography is necessary as a tool for monitoring interventions on the liver or in the biliary tree, for example for biopsy. Sonography is the most important imaging modality in cancer.

The use of ultrasound

Hepatic steatosis

Hepatic steatosis is the most common pathology of this organ. The sensitivity and specificity of the detection of hepatic steatosis by ultrasound is very high, and with transabdominal ultrasound, hepatic steatosis is characterized by increased echogenicity.

Cirrhosis of the liver

The accuracy of ultrasound in the diagnosis of liver cirrhosis in patients is high (> 90%). In the initial stage and in micronodular cirrhosis, the accuracy can be reduced to 30%. Sonographic features of cirrhosis include heterogeneous echotexture and uneven nodularity of the liver surface and many other possible abnormalities, including disrupted vascular architecture, also dependent on disease etiology.

Chronic viral hepatitis

With hepatitis B and C, signs of diffuse liver damage are revealed.

Primary biliary cirrhosis

The echo texture of the parenchyma in patients with primary biliary cirrhosis at stages I and II is often not expressive. Stage IV shows typical signs of liver cirrhosis.

Liver cyst

Cysts are common and easily diagnosed using routine ultrasound. Liver cysts are characterized by strong posterior wall echogenicity and post-cystic enhancement due to pulse difference.

Hemangioma

Hepatic hemangiomas are known to be the most common benign liver tumors.

Abscess

If a liver abscess is suspected, with the help of ultrasound it is possible to recognize the pathological focus in the parenchyma of the organ.

An ultrasound examination may be indicated in such cases if:

• there is pain in the right hypochondrium, which occurs and intensifies after drinking alcohol, fatty and fried foods, or after physical exertion;
• the skin changes its color, acquires a yellow, or yellow-gray color;
• a history of diseases of the pancreas or gallbladder;
• there is a suspicion of a neoplasm in the liver;
• there was an injury to the abdominal cavity, and there is suspicion of liver damage;
• there is a suspicion of a liver abscess;
• the patient has a history of drug or alcohol abuse;
• the patient takes long-term medications that can damage the liver;
• the patient has laboratory evidence of liver disease;
• disease control is required.

Doppler ultrasound is used to diagnose the following conditions:

• hypoplasia and aplasia of the common hepatic artery and / or its branches with atrophy of the associated segments of the liver;
• aneurysms of the common hepatic artery and its branches;
• atypical vascular directions;
• arteriovenous and arterioportal shunts;
• abnormal vascular malformations, more commonly associated with vascular changes in other organs (heart, lungs, brain, and kidneys), which usually determine the clinical course and prognosis.

Ultrasound examination of the liver is rarely performed separately, most often they diagnose diseases of the hepato-biliary tract, which includes, in addition to the liver, the gallbladder and bile ducts, since their pathology is often interconnected. Or, to diagnose various disorders of the digestive tract, a comprehensive ultrasound examination of the abdominal organs is performed. Also, ultrasound of this organ is carried out together with ultrasound diagnostics of the pancreas.

Normal ultrasound of the liver

Normal ultrasound readings:

1. The size. The size of the liver has been measured by many methods, including ultrasound. The normal dimensions of the liver are: thickness of the right 11,2-12,6 cm, vertical oblique size is 15 cm, length of the right lobe 11-15 cm, thickness of the left lobe approximately 7 cm, height of the left lobe ≤ 10 cm, total length 14-18 cm, the cross section of the organ is 20,1-22,5 cm, the sagittal size is 9-12 cm.
2. Form and structure. The normal form is described as pyramidal, the structure is homogeneous.
3. Circuit. The normal surface of the liver should be smooth, without protrusions or indentations. The lower border of the liver in a patient should normally have a sharp angular edge.
4. Texture, echogenicity. The normal liver parenchyma has an average homogeneous echogenicity, usually slightly darker than the spleen and slightly brighter than the renal cortex regardless of age, except in children. This is important when compared with the spleen and renal cortex.
5. Vienna. Three hepatic veins are located between the segments. They go to Glisson’s capsule – this is useful in determining the lobes and segments of the liver. The number and direction of the liver veins is somewhat variable.
6. portal vein. Formed by the confluence of the splenic and superior mesenteric veins, the portal vein can be visualized sonographically preferably in a left descended position and during deep inspiration. Inside the liver, the portal vein bifurcates into the main left and right branches. The first (right) branch of the portal vein splits into an anterior and a posterior branch that leads to segments V–VIII. The second (left) branch bifurcates into segments II and III and, in addition, into left medial branches for segments I (caudal lobe), IVa, and IVb.
7. hepatic artery. The common hepatic artery branches into the gastroduodenal artery and the hepatic artery proper (hepatica propria). There are often anatomical variations (up to 50%), such as the origin of the left hepatic artery from the left gastric artery, as well as variable arterial supply of the liver with the help of the superior branches of the mesenteric artery.
8. Bile ducts. The bile ducts accompany branches of the portal vein and hepatic artery from the liver to the liver lobules.

Preparing the patient for the procedure

It is recommended that the patient be fasted prior to an abdominal ultrasound, i.e. the ultrasound should preferably be performed on an empty stomach for better visualization to maximize gallbladder distension and reduce upper digestive tract food and gas residues that can reduce image quality or render the liver impossible to visualize. . This is necessary for complete visualization of the liver and associated bile ducts, but in an acute trauma situation, imaging of the gallbladder may not be necessary. The patient is allowed to drink a small amount of water prior to the scan, especially for taking any medication. There is some evidence that smoking may reduce the image quality of upper abdominal scans, and it is advisable that the patient should not smoke for 6-8 hours prior to the ultrasound. Smoking also increases the movement of gas into the upper gastrointestinal tract and may reduce image quality. In addition, certain chemicals in tobacco are known to cause gastrointestinal smooth muscle contraction and this may result in gallbladder contraction even if the test is done on an empty stomach.

What happens during the procedure

After placing the patient in the position required for diagnosis, a special gel is used to improve the contact of the sensor with the area of ​​the body being examined. The transducer is placed over the area of ​​interest over the gel and moved to capture the image. The transducer emits high-frequency sound and registers echoes that determine the size, shape, and consistency of soft tissues and organs.

The transducer sends out sound waves and receives echoes to produce ultrasound images that are displayed in real time on a computer screen.

Ultrasound examinations are painless.

What to Expect After an Ultrasound

After obtaining a high-quality image, the gel is removed from the surface of the skin. The standard ultrasound procedure usually takes up to 30 minutes, after which the patient can leave and return to their normal life.

The doctor will then analyze and interpret the images to detect any abnormalities.

Ultrasound in children

An ultrasound examination of a child is performed according to the following indications: hepatitis, jaundice, hepatomegaly, trauma in the liver area, if neoplasms are suspected, to detect parasites, etc.

Children are advised to follow a diet before the procedure that limits the intake of foods that contribute to gas formation, as well as not to eat high-calorie foods, it is advisable to take the test on an empty stomach, or eat food 6 hours before the test. The study is carried out in the same way as in adults, the results are available immediately after the examination, after which they need to be discussed with the attending physician.

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