X-ray signs of liver and biliary tract diseases

Recognition of liver and biliary tract diseases is currently the result of collective efforts of therapists, surgeons, radiation diagnosticians, laboratory doctors and other specialists. Radiation methods occupy an important place in the complex of diagnostic measures.

Diffuse liver lesions. Accurate diagnosis of diffuse lesions is based on anamnestic and clinical data, results of biochemical studies and, in some cases, liver biopsy. Radiation methods usually play only an auxiliary role. An exception is fatty hepatosis. Fat absorbs X-ray radiation worse than other soft tissues, so the liver shadow in fatty hepatosis on CT scans is characterized by low density.

In hepatitis, X-ray, sonograms and scintigrams show a uniform enlargement of the liver. Both sonograms and scintigrams may show slight heterogeneity of the image. The spleen is moderately enlarged.

Significantly more pronounced are the radiation symptoms of liver cirrhosis. The liver is enlarged, its edge is uneven. Later, a decrease and deformation of the right lobe of the liver may be observed. An enlarged spleen is always noticeable. Scintigraphy with colloidal solutions shows a significant increase in the radioactivity of the spleen, while in the liver the concentration of the radiopharmaceutical decreases. Foci of decreased accumulation of the radiopharmaceutical in areas of connective tissue proliferation and, conversely, increased accumulation in regeneration nodes are detected. The motley appearance of the organ is especially clearly determined by layer-by-layer radionuclide examination - emission single-photon tomography. Hepatobiliary scintigraphy reveals signs of impaired hepatocyte function: the liver radioactivity curve reaches its maximum late, 20-25 minutes after the start of the study, the plateau of the curve lengthens (a sign of intrahepatic cholestasis), the bile ducts are contrasted late.

Sonograms confirm the heterogeneity of the liver structure: its image reveals multiple foci of varying echogenicity - decreased and increased. MRI and CT allow us to detect areas of regeneration among cirrhotic fields. The branches of the portal vein in the liver are narrowed, and the portal vein itself and the splenic vein are dilated, since cirrhosis leads to portal hypertension. Sonography and CT establish the presence of effusion in the abdominal cavity. Varicose veins - a consequence of portal hypertension - can be detected on computer tomograms and angiograms.

Varicose veins of the esophagus and stomach are quite clearly revealed during X-ray examination of the upper digestive tract with barium sulfate. Against the background of folds of the mucous membrane of the esophagus and, to a lesser extent, the stomach, varicose nodes form round, oval and serpentine stripes of enlightenment - filling defects.

Patients with liver cirrhosis are always shown an X-ray examination of the esophagus and stomach with barium sulfate.

In cirrhosis, all vascular systems of the liver are involved in the process. The hepatic artery and especially its branches are sharply narrowed, while the gastric and splenic arteries are dilated. This is clearly demonstrated by angiography. In the parenchymatous phase of angiography, the liver is unevenly contrasted. In most areas, the tissue pattern is depleted, while in the regeneration nodes, hypervascularization zones are noted. During the return (venous) phase, it is possible to document collateral blood flow pathways, varicose veins, including in the esophagus and stomach, dilation of the splenoportal trunk and, at the same time, deformation and narrowing of the intrahepatic portal vessels.

Focal liver lesions. Focal (volumetric) liver lesions include cysts, abscesses, and tumors. Fluid-filled cysts are the most reliably recognized. On sonograms, such a cyst looks like an echo-negative round formation with clear, even contours and a thin wall. There are both single and multiple cysts of varying sizes. Cysts smaller than 0.5-1.0 cm in diameter are not determined if there are no calcifications in their capsule. Marginal annular calcifications are most typical for echo-cojugular cysts. One of the varieties of cystic liver lesions is polycystic disease, in which most of the organ parenchyma is replaced by fluid-containing cavities. In this disease, cysts can also be found in the kidneys and pancreas.

On computer and magnetic resonance tomograms, a cyst is reflected as a round formation with smooth contours containing fluid. Cysts are especially clearly visible on enhanced computer tomograms, i.e. obtained after the introduction of contrast agents. The spatial resolution of CT and MRI is much higher than that of sonography. These studies can detect cystic formations with a diameter of only 2-3 mm. Liver scintigraphy is rarely used to detect cysts due to its low spatial resolution.

Liver abscess, like cyst, causes a limited image defect on sonograms, scintigrams, CT and MRI scans. In addition to clinical data, additional signs help to distinguish these two lesions. First, an abscess is usually surrounded by a zone of altered tissue. Second, the outlines of an abscess are less even than cysts, and in terms of densitometric density on CT scans it surpasses the cyst. Small pyogenic abscesses are usually located in groups, and seals are often visible in them - along the edge or in the center of the cavity.

Most benign liver tumors are hemangiomas, less common are adenoma and nodular hyperplasia. On sonograms, they are visible as hyperechoic formations of a round or oval shape with clear contours and a homogeneous structure. On CT scans, hemangioma causes a limited area of low density of a heterogeneous structure with uneven outlines. With enhanced CT, an increase in the densitometric density of the affected area is noted. Adenoma gives a similar picture on CT scans, but when enhanced with a contrast agent, its shadow is less intense than the surrounding liver tissue. With nodular hyperplasia, multiple small hypodense foci are detected on CT scans. Hemangioma is quite clearly outlined in MRI, especially when this study is combined with contrasting with paramagnetics. As for radionuclide visualization, in terms of spatial resolution it is inferior to all the listed methods of liver visualization and is currently rarely used for this purpose.

Hepatocellular carcinoma (hepatoma) causes an area of uneven density with irregular contours on sonograms. Tumor decay appears as an echo-negative zone of irregular shape, and edema around the tumor appears as a vague rim, also echo-negative. On computer, magnetic resonance tomograms and scintigrams (emission tomograms), hepatoma causes a defect of irregular shape with irregular contours.

The radiographic picture of metastases of malignant tumors in the liver (and this is, unfortunately, a common lesion) depends on the number and size of tumor nodes.

Among all the means of visualizing metastases, CT has the best spatial resolution, especially when performed using an enhanced technique, followed by MRI, and sonography and scintigraphy complete the above-mentioned group.

Examination of such patients usually begins with sonography as the most accessible and inexpensive method. In our country, in oncology dispensaries, according to established tradition, in addition to sonography, liver scintigraphy is performed on most patients with malignant neoplasms in order to detect metastases. However, gradually, as the material base of these medical institutions develops and strengthens, CT is becoming increasingly important in detecting liver metastases. Note also that in the presence of metastases, as with other volumetric processes in the liver (primary malignant or benign tumor, abscess), AT and sonography allow for targeted puncture of the pathological formation, taking tissue for histological (or cytological) examination and, if necessary, introducing the necessary drug into the affected area.

Patients with small hepatocellular malignancies and solitary metastases (in particular, colorectal cancer) are treated under the control of radiation studies. Either percutaneous injections of ethanol into the tumor node or laser irradiation via optical fibers, also percutaneously introduced into the tumor, are used. Sonograms and tomograms allow evaluating the results of treatment. Intraoperative sonography is a valuable aid in surgical interventions on the liver. A sterile ultrasound sensor brought to the liver makes it possible to clarify the anatomical variants of branching of vessels and ducts of the liver and to detect previously unnoticed additional tumor nodules.

Diseases of the biliary tract. In recent years, the incidence of gallstone disease has increased significantly. According to composition, there are cholesterol, pigment, calcareous and mixed (cholesterol-pigment-calcareous) stones.

Sonography plays a decisive role in the diagnosis of gallstones. Its sensitivity reaches 95-99%, and the limit of stone detection is 1.5-2 mm. A stone on a sonogram causes a hyperechoic formation in the gallbladder cavity. An acoustic shadow is determined behind the stone - a "sound track".

Gallstones can be recognized on conventional radiographs only if they contain calcified deposits. Other stones are detected by cholecystography if the cystic duct is passable and contrasted bile enters the gallbladder. Stones create defects in the shadow of the gallbladder. The number, size, and shape of the defects depend on the number, size, and shape of the stones. Stones are clearly detected by CT. With the development of sonography, cholecystography, which was the main method for detecting stones in the gallbladder, has lost its significance.

Bile duct stones are rarely detected by sonography, since they are usually small; in addition, some part of the common bile duct is covered by the duodenum, which impairs ultrasound visualization of this part of the biliary system. In this regard, the main method of visualizing bile duct stones is CT, and only if it is not possible to perform it, cholegraphy can be prescribed. The picture of bile duct stones on MRI is indicative. In mechanical jaundice, important diagnostic data can be obtained using ERCP. In recent years, interventional methods of treating cholelithiasis have become increasingly widespread. Under ultrasound or CT control, percutaneous puncture of the gallbladder, its catheterization and subsequent administration of drugs (aliphatic alcohols) that dissolve stones are performed. Methods of extracorporeal shock wave lithotripsy have also come into practice. X-ray surgical interventions used for occlusive lesions of the bile ducts are rapidly developing. Special catheters are inserted into the liver via percutaneous access, and through them the necessary instruments are inserted to remove gallstones left behind during surgery, eliminate strictures, place a drainage tube in the ducts for biliary decompression and external or internal drainage of the bile ducts.

Radiation methods are a valuable aid to the clinician in diagnosing cholecystitis. Firstly, they allow one to immediately differentiate calculus. Secondly, they help to identify a group of patients with inflammatory stenosis of the terminal section of the common bile duct. Thirdly, they make it possible to establish the patency of the cystic duct and the degree of impairment of the concentration and motor functions of the gallbladder, which is very important when planning treatment, especially when deciding on surgical intervention.

In acute cholecystitis, the primary method of examination is sonography. It reveals an increase in the size of the bladder, thickening of its wall. An edema zone appears around the bladder. A very common finding in sonography is intravesical gallstones; they are observed in 90-95% of patients with acute cholecystitis. All these symptoms are quite clearly revealed by CT, but with positive sonographic and clinical data, it is not often performed. An indirect sign of cholecystitis in sonography may be limited mobility of the right half of the diaphragm during breathing. Note that this symptom is also revealed by X-ray examination of the chest organs - fluoroscopy.

Chronic cholecystitis is manifested by similar signs in sonography: the size of the bladder is often enlarged, less often, when the bladder is shriveled, it is reduced, its walls are thickened, sometimes uneven, the liver tissue surrounding the bladder is usually compacted, stones or deposited dense components of bile are often visible in the bladder. In some cases, the bladder is significantly deformed due to sclerosing pericholecystitis. The latter symptom should be assessed with great caution. It should be remembered that 8% of healthy people have congenital deformations of the gallbladder, sometimes quite bizarre. All of the listed symptoms can also be detected using other methods of radiation visualization - CT and MRI. Hepatobiliary scintigraphy allows detecting bladder dyskinesia of varying degrees of severity, up to a complete loss of its concentration function and contractility.

Radiation methods and biliary tract surgery are inextricably linked. Ultrasound monitoring expands the capabilities of laparoscopic surgery. Papillotomy and sphincterotomy are performed under ERCP control. Percutaneous transhepatic cholangiography is a mandatory preliminary procedure before percutaneous drainage of the bile ducts and the introduction of various instruments into them, in particular for dilatation of narrowed sections of the ducts. Cholangiography through a drainage tube is used to detect gallstones left during surgery. Venoportography is used to assess the function of the hepatic-portal anastomosis imposed on a patient with liver cirrhosis. It is quite clear that the main radiation methods - sonography, CT and MRI - are necessary for liver transplantation.

Portal hypertension syndrome. The term "portal hypertension" refers to increased pressure in the portal vein system. A distinction is made between suprahepatic blockade, when hypertension is caused by impaired blood outflow from the liver due to compression or thrombosis of the inferior vena cava, thrombophlebitis of the hepatic veins, constrictive pericarditis, intrahepatic blockade, mainly in liver cirrhosis, and subhepatic blockade caused by a developmental anomaly, thrombosis, or compression of the trunk of the portal vein itself.

In portal hypertension, varicose veins of the esophagus and stomach are observed, which can be complicated by bleeding. To assess the localization and severity of varicose veins, X-ray examination of the esophagus and stomach with barium sulfate, endoesophageal sonography or angiography (CT or MRI angiography) are used. A catheter is inserted into the portal vein via transhepatic access, and then embolization of varicose veins is performed.

Abdominal trauma. The location and nature of the X-ray examination for blunt abdominal trauma or wounds from a gunshot or bladed weapon depend on the condition of the victim. In moderate cases, the examination is conducted in the X-ray diagnostics department. Clinically unstable patients (serious condition, shock) must be examined in the intensive care unit. Victims requiring emergency surgery are examined directly on the operating table. In all cases, the following procedure is followed.

Chest X-ray is important to rule out associated thoracoabdominal injury; chest bone fractures, traumatic lung collapse, and pneumonia may also be detected.

Sonography allows to establish an enlargement of the affected organ, a break in its contour, the presence of subcapsular or intraorgan hematomas, the presence of fluid (blood, bile) in the abdominal cavity. CT is more effective than sonography, since the latter is hampered by flatulence, which is usually observed with abdominal trauma. Damage to the abdominal wall can also interfere with sonography. CT is a "sensitive" method for detecting fluid in the abdominal cavity. The presence of fluid suggests damage to the intestine or mesentery. Recently, greater capabilities have been shown for spiral computed tomography, performed after oral administration of 500 ml of a 2-5% solution of a water-soluble contrast agent. A series of tomograms makes it possible to recognize bruises and ruptures of abdominal organs, hematomas and hemoperitoneum, bile accumulations (bilomas), pseudoaneurysms, venous thrombosis, etc. In unclear cases, decisive information is obtained from angiography. It allows to establish the source of bleeding, rupture of certain vessels. It can be used to perform therapeutic procedures, such as the administration of hemostatic drugs or embolization of a bleeding vessel.