Hepatobiliscintigraphy

Hepatobiliary scintigraphy is a functional-morphological method intended for studying the cholerative and bile excretory functions of the liver. On a series of scintigrams made at intervals of 2-5 minutes immediately after intravenous RFP, after 10-12 min after the appearance of the image of the liver, the bile ducts begin to be visualized, and a little later, after 3-4 minutes, an image of the gallbladder appears. In healthy people, the maximum radioactivity above the liver is recorded after about 12 minutes. By this time, the radioactivity curve reaches its maximum. Then it acquires a plateau character: during this period, the rate of capture and excretion of RFP by hepatocytes counterbalances each other. As the RFP is excreted with bile, the radioactivity of the liver decreases (by 50% over 30 min), and the intensity of radiation above the gall bladder begins to increase. In order to force the allocation of RFP with bile in the intestine, the patient is given a fat breakfast. After it, the emptying of the bladder is significantly accelerated, its image on the scintigram begins to progressively decrease, and the increasing radioactivity is recorded above the intestine. In the same way, it is possible to assess the patency of the biliary tract.

Choosing several "zones of interest" on the scintigrams (liver, gallbladder, bile ducts, intestines), you can build curves on the computer that reflect the passage of the RFP through the liver system-the bile ducts-the gall-bladder-the intestine. Based on the analysis of these curves, one can study the functional parameters of this system.

Hepatobiliary scintigraphy is indicated for all disorders of the bile excretory system: cholestasis of various nature, disknecia, developmental anomalies (eg, bile duct agenesis in children), pathological anastomoses, etc. Simultaneously, this method provides an idea of the detoxification function of the liver.

When hepatoscintigraphy, as in hepatobiliary scintigraphy, a series of images of the liver are obtained after intravenous administration of the corresponding RFP with an interval of several minutes. According to the first scintigrams, the vascularization of the organ is judged, followed by the functional activity of stellate reticuloendotheliocytes, but the main thing is the topography and macrostructure of the organ (position, shape, size, presence of focal formations). Of course, colloidal particles are trapped from the blood by reticuloendotheliocytes not only of the liver, but also found in the spleen and bone marrow. Normally, the liver captures about 90% of the RFP injected, so only its image is present on the scintigrams. When the liver is damaged on scintigraphs, along with the image of the liver (which is always weakened), an image of the spleen appears, and in some cases also of the bone marrow. Thus, this symptom - the appearance on the scintigraphy of the image of the spleen and bone marrow serves as an indirect sign of the failure of the liver function. The main indication for hepatoscintigraphy is the obtaining of an indicative functional and topographic characteristic of the liver, which is necessary for examination of patients with hepatitis, cirrhosis, and focal liver lesions of various nature.

From the data given, we can see what wide opportunities the expert in the field of radiation diagnosis has in the investigation of the liver and biliary tract. However, this is not all. According to the indications, a radiocontrast study of the vascular system of the liver is performed. By catheterization, a contrast agent is injected into the celiac trunk that extends from the abdominal aorta and a series of angiograms is performed. Thanks to this method, an image of the entire system of the celiac trunk and its branches is obtained. It depicts the left gastric and splenic arteries, the common hepatic artery, the gastroduodenal artery, its own hepatic artery and its branches in the liver. In the final phase of the goal, the contrast medium, passing through the arteries and the capillary network, appears in the veins and gives images of the splenic and gastric veins in the pictures, and finally, the portal vein - a return splenoportography. It should be noted that during the X-ray study of arterial vessels of the abdominal cavity preference is given to digital imaging methods - digital subtraction angiography. In this case, it is possible to get rid of the interfering shadows of the spine and abdominal organs and to obtain higher quality angiograms.

There are methods of direct contrasting of the portal vein. To do this, the contrast substance is injected through the puncture of the skin into the pulp of the spleen near its gate, from where the contrast material enters the portal vein - splenoportography. A transcutaneous (transparietal) puncture of one of the branches of the portal vein in the liver is also performed and the main trunk of the portal vein is retrograded-the percutaneous transhepatic portography.

The diameter of the portal vein is 14-16 cm. The shadow of the lenoportal trunk is intense, homogeneous, has straight contours. The intrahepatic portal system is a rich network of vessels. The peripheral lumen of the veins gradually narrows. In order to examine the trunks of the right, middle and left hepatic veins, they perform catheterization from the inferior vena cava with subsequent serial angiography.

An important instrumental non-invasive method for studying the blood flow in the liver and the vessels supporting it (hepatic artery, splenic, portal and hepatic veins, inferior vena cava) is Doppler ultrasound, especially color Doppler mapping.

[1], [2], [3], [4], [5], [6], [7], [8], [9]