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X-ray of the liver and biliary tract
Last reviewed: 23.11.2021
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The liver is one of the most complex in structure and functions of organs, is the largest gland in the body, takes part in the processes of digestion, metabolism and circulation, and performs specific enzymatic and excretory functions. With the help of a variety of research methods, doctors learned to objectively evaluate the morphology of the liver and to learn its multifaceted functions. Among these techniques, ray methods took a worthy place. This completely applies also to the study of the biliary tract and pancreas. Here, radiation diagnostics has won the leading position without exaggeration, but provided that it is considered as an integral part of the general diagnostic scheme.
Indications for X-ray of the liver and biliary tract
Indication for x-ray examination (roentgen) of the liver and biliary tract is established by the clinician on the basis of anamnesis and clinical picture of the disease. The choice of the method of radiation research is carried out jointly by the clinician and radiation diagnostician. The latter composes the research plan, analyzes its results and formulates a conclusion.
X-ray examination of the liver and biliary tract
The liver consists of two parts, which are usually divided into 8 segments. Each segment includes a branch of the portal vein and a branch of the hepatic artery, and a bile duct emerges from the segment. Segments I and II constitute the left lobe of the liver, and III-VIII is the right lobe. The main cellular mass of the liver - about 85% of all cells - form hepatocytes. They are collected in lobules, which in the liver are about 500 000. Hepatocytes in lobules are arranged in rows along the bile capillaries and the tiniest venous branches. The walls of the latter consist of stellate reticuloendotheliocytes - Kupffer cells, they constitute 15% of all hepatic cells.
The circulatory system of the liver includes two blood vessels that bring blood: a portal vein, through which 70-80% of the total incoming blood flows, and a hepatic artery, which accounts for 20-30%. The outflow of blood from the liver occurs through the hepatic veins that go to the inferior vena cava, and the outflow of lymph - through the lymphatic ways.
On the overview radiographs, the liver produces an intense uniform shadow of approximately triangular shape. Its upper contour coincides with the image of the diaphragm, the outer one stands out against the background of extraperitoneal fatty tissue, and the lower one corresponds to the anterior margin and looms against the background of other organs of the abdominal cavity. A normal gallbladder in ordinary pictures is rarely seen, and then mostly in the bottom.
With ultrasound, the image of a healthy person's liver is fairly uniform, with a fine-grained echostructure due to stromal elements, vessels, bile ducts and ligaments. The border between the right and left lobes of the liver is oval hyperechoic formation - a display of the circular ligament of the liver.
Thin-walled tubular formations are defined in the region of the liver gates. This is primarily a portal vein with its relatively thick walls and caliber of the main trunk of 1-1.2 cm, hepatic arteries, as well as a common bile duct with a diameter of about 0.7 cm. Inside the liver, arteries and bile ducts are invisible, but clearly marked by echonogenic bands venous vessels. Particularly clear are the hepatic veins that are directed to the inferior vena cava.
On sonograms, the gallbladder differs well as a uniform echo-negative formation of an oval shape with even margins. Its dimensions vary widely - from 6 to 12 cm in length and from 2.5 to 4 cm in width. The thickness of the gallbladder wall in the region of the bottom and body is 2 mm, in the funnel and neck area - 3 mm.
The image of the liver on computer tomograms depends on the level of the excreted layer. If you go from above, then at the height of Thix-ThX appears the shadow of the right lobe, and at the ThX-ThXI - and the left lobe. In subsequent sections, a homogeneous liver structure with a density of 50-70 HU is found. The contours of the liver are even and sharp. On the background of liver tissue can be determined images of blood vessels; the density of their shadow is lower (30-50 HU). The gates of the liver are clearly visible, at the posterior margin of which the portal vein is determined, and anterior to and to the right of it is the common bile duct (normally appears indistinctly). At the ThXI-ThXII level, a picture of the gallbladder is noted. On spiral tomographs it is possible to investigate the vascular system of the liver. For this purpose, the tomography is performed with the patient's breathing delayed after the bolus water-soluble contrast agent is injected into the venous bed.
The possibilities of magnetic resonance imaging of the liver are similar to those of CT, but with MRI it is possible to obtain an image of the layers of the liver in all planes. In addition, by varying the method of magnetic resonance imaging, it is possible to obtain an image of the liver vessels (MR-angiography), bile ducts and pancreatic ducts.
For radiographic examination of the gallbladder and bile ducts, a number of methods for their artificial contrasting have been developed. They are divided into three groups:
Of the methods of radiographic examination, the most attention deserves angiographic methods and studies with the introduction of contrast media in the biliary and pancreatic courses. These methods are of great importance for the differential diagnosis of liver cirrhosis, biliary atresia, portal hypertension, recognition of the volumetric process in the liver and biliary tract. Based on the results of these studies, patients are selected for surgical treatment.
The method with contrasting of the esophagus with barium for the detection of varicose veins is being used less and less, as endoscopic research gives much better results. The survey radiograph of the abdominal cavity also loses its clinical significance for the diagnosis of liver diseases.
Angiography of the liver
Angiography of the liver has acquired great clinical significance with the introduction of selective angiography of the visceral branches of the abdominal aorta. Among angiographic methods, the most common are celiac and mesentericography. Angiography is used to identify the pathological process and refine its features, as well as to address the issue of surgical treatment. The method is used for the diagnosis of focal lesions of the liver, recognition of tumors, parasitic diseases, malformations and own vascular pathology in this zone. The method is contraindicated in case of severe patient condition, acute infectious diseases, mental disorders, hypersensitivity to iodine preparations.
[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]
Splenoportography
Splenoportograficheskoe study consists in the introduction of contrast medium in the spleen followed by radiography. The system of portal and splenic veins is clearly contoured on the roentgenogram, which allows to reveal violations of the portal circulation, the presence of collaterals and even focal lesions of the liver and spleen. Indications for splenoportography are splenomegaly, hepatomegaly, gastric bleeding of unclear etiology. In the presence of portal hypertension, the entire system of splenic and portal veins, deformation of the vascular pattern of the liver with sites of thrombosis, and the presence of collateral blood flow are noted.
To clarify the origin of portal hypertension, splenoportocholangiography can be used. Its essence lies in the fact that the spleen is injected with readily secreted by the liver contrast substances (billing, etc.). This method allows us not only to assess the condition of the portal blood circulation, but also to determine the patency of the bile ducts.
Hepatovenography
In addition, in clinical practice, hepatovenography (hepatic phlebography) is used. The method is used to diagnose Badca-Chiari syndrome, to clarify the state of outflow from the liver before the operation of the shunt in patients with cirrhosis of the liver.
Direct portography
Direct portography (ileomezentikoportografiya) is most widely used in surgical practice to clarify the causes and severity of portal blood circulation disorder: conditions of the outside and intrahepatic portal channel, the presence of collaterals that are not contrasted with slenoporgography. Direct portography in conjunction with other special research methods allows you to determine the scope of surgical intervention. Of particular importance is direct portography for patients with portal hypertension syndrome after surgery, when it is necessary to solve the problem of imposing a mesenteric-caval anastomosis. The mesenteric vessels are used for the study.
[11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21]
Cholecystocholangiography
Oral and intravenous cholecystocholangiography in acute diseases is poorly informative, as affected hepatocytes excrete bile contrast substances. These survey methods give the best results in the period of convalescence of viral hepatitis, with isolated pathology of the biliary tract, as well as in chronic hepatitis.
[22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33]
Pancreatocholangiography
Endoscopic retrograde pancreatocholangiography (ERCPH) is used in cases where other methods fail to establish the cause of cholestasis. Prior diagnostics include careful collection of anamnesis, examination of the patient, ultrasound and (or) CT, if possible, intravenous contrast. Endoscopic retrograde pancreatocholangiography is of great importance in the recognition of pancreatic and biliary tract diseases. The study includes fibroduodenoscopy, cannulation of the large duodenal papilla by a catheter, the introduction of a contrast agent (vero- graphene) into the biliary and pancreatic passages and radiopaque studies. The method is used to diagnose choledocholithiasis, tumors of intra- and extrahepatic bile ducts, periholedoistnogo lymphadenitis, pancreatic cancer.
In addition, with combined liver damage and bile ducts for differential diagnosis of mechanical and hepatocellular jaundice, transhepatic (transparietal) cholangiography can be used, consisting in the introduction of a contrast agent into the intrahepatic bile ducts by puncture liver biopsy. Since at the same time the bile ducts are well contrasted on the roentgenogram, it is possible to determine the localization of the obturation and the genesis of the onset of cholestasis. However, this method of research in children is rarely used.