X-ray of the pancreas

The pancreas is located retroperitoneally. Its head is located to the right of the midline in the loop of the duodenum, and the tail extends towards the splenic hilum. The total length of the gland is 12-15 cm, width - 3-6 cm, thickness 2-4 cm. The secretion of the gland is released through the pancreatic duct (Wirsung's duct), the diameter of which usually does not exceed 2-3 mm. It opens into the duodenum together with the common bile duct through the large duodenal papilla. The accessory pancreatic duct (Santorini's duct) opens through the small duodenal papilla.

On plain radiographs of the abdominal cavity, the pancreas is indistinguishable. The only exceptions are rare cases of calcification - parenchyma, pseudocyst walls and stones in the ducts in chronic pancreatitis. Plain images, as well as contrast radiographic examination of the stomach and intestines, can reveal indirect signs of damage to the gland. Thus, with volumetric lesions, the loops of the small intestine are pushed apart, the distance between the stomach and the transverse colon increases. Volumetric processes in the head of the gland are especially clearly manifested from the side of the duodenal loop: it expands, the intestinal walls are deformed, its descending part takes the form of an "inverted three" (Frostberg symptom). In acute pancreatitis, chest radiographs can reveal infiltrates in the basal parts of the lungs and pleural effusion.

Sonography is the primary method of examining the pancreas. On sonograms, the gland is revealed as an elongated, not entirely uniform strip between the left lobe of the liver and the stomach in front and the inferior vena cava, abdominal aorta, spine and splenic vein behind. Other anatomical structures can be identified near the gland: the superior mesenteric artery and vein, splenic artery, hepatic artery, portal vein. The echogenicity of the gland is usually somewhat higher than that of the liver. It should be taken into account that the pancreas is not visible on sonograms in all individuals. In approximately 20% of patients, ultrasound localization of the gland is difficult due to intestinal loops distended with gas. The duct of the gland is detected on sonograms only in 1/3 of patients. Color Doppler mapping provides certain useful information. It allows assessing the intraorgan blood flow, which is used in the differential diagnosis of volumetric lesions. The spatial resolution of sonography in the diagnosis of volumetric processes in the pancreas is about 1 cm.

Computer tomography provides extremely important information about the condition of the pancreas. Its spatial resolution is significantly better than that of sonography and is about 3-4 mm. CT allows for an accurate assessment of the condition of the gland itself, as well as other organs: bile ducts, kidneys, spleen, mesentery, intestines. A significant advantage of CT over sonography is the ability to visualize the gland in cases where ultrasound is powerless - in conditions of severe flatulence. For differential diagnostics of volumetric lesions, CT with amplification is used, i.e. the introduction of contrast agents. MRI and scintigraphy are currently of limited value in examining patients with pancreatic lesions.

Endoscopic retrograde cholangiopancreatography (ERCP) is an important diagnostic study of the pancreatic ducts and, to some extent, its parenchyma. This method allows assessing the patency of the ducts in cancer and pancreatitis, which is extremely important when planning surgical treatment, and also to identify pathological communication of the ducts with cystic formations.

Pancreatic angiography is currently used rarely, mainly for differential diagnosis of endocrine tumors of the gland and in some cases to clarify the nature of surgical intervention. The celiac trunk and superior mesenteric artery are contrasted.

Interventional methods for examining the pancreas include fine-needle biopsy, drainage, and embolization. Fine-needle biopsy is performed under sonography or CT control. It allows one to examine the contents of a cyst or abscess, and perform a biopsy of tumor tissue. Percutaneous drainage is used to treat abscesses and cysts. In some cases, internal drainage of pancreatic pseudocysts into the stomach or intestines is used. This makes it possible to avoid surgical intervention in patients for whom it is contraindicated for some reason. Embolization of pancreatic arteries is performed in the presence of aneurysms, which can occur as complications of chronic induration pancreatitis.

X-ray diagnostics of pancreatic lesions

Acute pancreatitis is diagnosed based on the results of not only a clinical examination and laboratory tests (in particular, an increase in the concentration of trypsin in the blood), but also mainly CT and MRI. CT determines an enlargement of the gland, an increase in its density due to edema. After a preliminary overview tomographic study, an enhanced CT is performed. This allows us to differentiate between acute edematous pancreatitis, in which an increase in the density of the gland shadow is observed after the introduction of a contrast agent, and the hemorrhagic-necrotic form of pancreatitis, in which such an increase in the density of the gland tissue in response to the introduction of a contrast agent does not occur. In addition, CT allows us to identify complications of pancreatitis - the formation of cysts and abscesses. Sonography is of lesser importance in this disease, since ultrasound visualization of the gland is generally difficult due to the presence of a large number of swollen intestinal loops.

In chronic pancreatitis, sonography results are more convincing. The gland may be enlarged or reduced (in fibrous pancreatitis). Even small lime deposits and stones, as well as pseudocysts, are well diagnosed. On CT scans, the outlines of the pancreas are uneven and not always clear, the tissue density is non-uniform. Abscesses and pseudocysts cause areas of reduced density (5-22 HU). Additional data can be obtained by ERCP. Pancreatograms reveal deformation of the ducts, their expansion, narrowing, non-filling, penetration of the contrast agent into pseudocysts.

Examination of patients with suspected pancreatic tumor begins with sonography. The tumor causes an increase in some part of the gland, most often its head. The contours of this section become uneven. The tumor node itself is visible as a homogeneous formation with uneven contours. If the cancerous tumor compresses or grows into the common bile and pancreatic ducts, they expand in places. At the same time, congestive enlargement of the gallbladder is detected, as well as compression of the splenic or portal vein. Metastases in the lymph nodes of the abdominal cavity and liver can be detected.

Computer tomograms reveal many similar signs: enlargement of the affected section or the entire pancreas, unevenness of its contours, dilation of the bile ducts, inhomogeneity of the gland structure in the tumor area. It is possible to establish tumor growth into vessels and adjacent tissues, metastases in the lymph nodes, liver, kidneys, etc. In doubtful cases, a contrast agent is administered. On enhanced computer tomograms, tumor nodes are displayed more clearly, since the increase in the density of their shadow noticeably lags behind the increase in the shadow of normal pancreatic tissue. The density of cystic formations on enhanced computer tomograms does not change at all.

A number of important symptoms are detected during ERCP. These include narrowing or amputation of the ducts (sometimes with expansion of the prestenotic section), destruction of the lateral branches of the duct, its displacement by the tumor, deformation of the terminal part of the common bile and pancreatic ducts.

The study of pancreatic function is carried out not only by laboratory diagnostics, but also by radioimmunological analysis. As is known, the pancreas performs two main physiological functions. Firstly, as an exocrine (exocrine) gland, it secretes juice containing enzymes that hydrolyze the main groups of food polymers into the duodenum. Secondly, as an endocrine (endocrine) gland, it secretes polypeptide hormones into the blood that regulate the assimilation of food and some metabolic processes in the body. Both the exocrine and endocrine functions of the gland are studied using radioimmune tests. The secretion of lipase by the gland is judged on the basis of whole-body radiometry of a person after ingestion of radioactive trioleate-glycerol. The content of trypsin is determined by the radioimmune method.

Insulin is involved in the breakdown of sugar and is the main regulator of blood glucose levels. It is produced by the β-cells of the pancreas in the form of proinsulin. The latter consists of two parts: a biologically active form - insulin itself, and an inactive form - C-peptide. These molecules are released into the blood. Insulin reaches the liver and participates in metabolism there. In this process, about 60% of it is inactivated, and the remainder returns to the bloodstream. C-peptide passes through the liver unchanged, and its concentration in the blood is maintained. Thus, although insulin and C-peptide are excreted by the pancreas in equal quantities, there is more of the latter in the blood than insulin.

The study of the hormonal and enzymatic activity of the pancreas is performed by means of loading tests with glucose. Using a standard test kit, the concentration of hormones is analyzed before, as well as 1 and 2 hours after taking 50 g of glucose. Normally, the concentration of insulin after taking glucose begins to increase, and then decreases to a normal level. In patients with latent diabetes and normal blood sugar levels, the insulin level in the blood increases slowly, with the maximum increase occurring after 90-120 minutes. In overt diabetes, the increase in insulin in response to a sugar load is even more suppressed, with the maximum recorded after 2-3 hours. The value of determining C-peptide is great in cases where patients have been treated with insulin for a long time, since it is not possible to determine insulin in the blood using the radioimmunological method.