Ultrasound signs of pathology of the gastrointestinal tract

Fluid in the abdominal cavity (ascites)

The patient should lie on his back, while the entire abdomen is examined, then every side is examined in an inclined position or in a position on the right or left side. In the presence of severe flatulence, the knee-elbow position of the patient is used. When searching for fluids, scan the lowest located areas of the abdomen in all projections. The fluid is visualized as an anechogenous zone.

Small amounts of fluid will be collected in two places in the stomach:

1. In women in the back bone space (in Douglas space).
2. In men in the hepatorenal cavity (in Morrison's pocket).

Ultrasound is an accurate method for determining free fluid in the abdominal cavity

If there is more fluid, the lateral pockets (the recesses between the parietal peritoneum and the large intestine) will be filled with liquid. When the amount of fluid increases, it will fill the entire abdominal cavity. The intestinal loops will float in the liquid, while the gas in the lumen of the intestine will collect at the anterior abdominal wall and move when the patient's position changes. When the mesentery thickens as a result of tumor infiltration or inflammation, the gut will be less mobile and the fluid between the abdominal wall and the intestinal loops will be determined.

Ultrasound can not distinguish ascites, blood, bile, pus and urine. Need for thin needle aspiration to determine the nature of the liquid

Adhesive process in the abdominal cavity can produce the formation of septa, while the fluid can be shielded by gas inside the intestine or by free gas. It may be necessary to conduct research in various positions.

Large cysts can simulate ascites. Examine the entire abdomen for free fluid, especially in the lateral canals and pelvis.

Under the control of ultrasound, small amounts of liquid can be aspirated, but certain skills are required for aspiration

[1], [2], [3]

The formation of the intestine

1. Solid formations in the intestine can be tumorous, inflammatory (eg, amoebae), or formations with ascariasis. The formations in the intestine usually have the form of a kidney. When ultrasound examination reveals thickening of the wall, unevenness, puffiness and fuzziness of the contours. Inflammation or tumor infiltration can cause intestinal fixation, and the appearance of fluid can occur as a result of perforation or bleeding. Clarifying organo-accessories can be complicated.

When detecting a tumor of the intestine, it is necessary to exclude liver metastases, as well as enlarged anechoic lymph nodes of the mesentery. Normal lymph nodes are rarely visualized by ultrasound.

2. Solid formations outside the intestine. Multiple, often confluent and hypoechoic formations are suspected of having lymphoma or enlarged lymph nodes. Children in the tropics may suspect the presence of Burkitt's lymphoma, while it is necessary to examine the kidneys and ovaries for the detection of the same tumors. Nevertheless, ultrasound differentiation of lymphoma and tuberculous lymphadenitis can be very difficult.

The retroperitoneal sarcoma is infrequent and can be represented by a large, solid structure of various echogenicity. Necrosis may occur in the center of the tumor. In this case, it is defined as a hypoechoic or mixed echogenic zone as a result of dilution.

3. Complex in structure of education

• Abscess: can be located anywhere in the abdomen or pelvis. He often gives pain, a concomitant fever, has fuzzy outlines. In addition to appendicular abscesses, there may be:
  • diverticulum of the large intestine with perforation: the abscess is usually localized in the left lower abdomen;
  • amebiasis with perforation: the abscess is usually located in the right lower abdomen, less often in the left half or somewhere else;
  • tumor perforation: the abscess can be detected anywhere;
  • tuberculosis or any other granulomatous inflammation: the abscess is usually detected in the right side of the abdomen, but can be anywhere else;
  • regional ileitis (Crohn's disease), ulcerative colitis, typhoid or other intestinal infection: abscesses can be detected everywhere;
  • perforation of parasites, for example Strongyloides, Ascaris or Oesophagostomum: an abscess is usually found in the right side of the abdomen, but can be seen everywhere. (Ascaris can be detected in cross-section in the form of long tubular structures)

Abscess is easy to detect, but it is rarely possible to determine the cause of abscess formation

4. • The hematoma looks like a cystic or mixed echogenic structure, similar to an abscess, but it does not give a fever. It is important to have an injury or anticoagulant therapy in the anamnesis. In the center of the hematoma may be a suspension or a dilution zone, in which septa can be determined. Also look for free fluid in the abdominal cavity.
5. Fluid containing formations. Most of them are benign, they are either congenital, or parasitic or have an inflammatory genesis).

4. • Doubling the intestine. This congenital anomaly is often determined in the form of liquid-containing structures of various shapes with a clearly traced wall. They can be small or large and can have an internal ehostrukturu due to the presence of suspended matter or partitions.
   • Lymphatic cysts or mesentery cysts. Although they are usually aneho-genes, septa can be identified, internal echostructure may or may not be determined. They can be localized in any part of the abdomen and have various sizes up to 20 cm or more in diameter.
5. Ischemia of the intestine. Ultrasound can detect a solid thickening of the intestinal wall, sometimes localized, but more often - extended. In this case, movable gas bubbles can be detected in the portal vein.
6. Echinococcal cysts (parasitic disease). Cysts in the abdominal cavity do not have any special characteristics and resemble other visceral parasitic cysts, especially the hepatic cysts. They are almost always multiple and are combined with cysts of other organs. (Perform an ultrasound examination of the liver and chest X-ray.) In detecting a cluster of multiple small cysts, less frequent alveococcosis (Echinococcus multHoculoris) can be suspected .

[4], [5], [6]

Suspicion of appendicitis

Ultrasonic diagnosis of acute appendicitis can be complex and even impossible. It takes some experience.

If suspected of acute appendicitis, examine the patient in the supine position using a 5 MHz sensor. Place the pillow under your knees to relax the abdomen, apply an optional gel to the lower right abdomen and start scanning longitudinally with a slight pressure on the sensor. To move the bowels, use a more pronounced push. If the intestinal loops are inflamed, then they will be fixed, they will not be determined by peristalsis: soreness will help determine the site of the lesion.

An inflamed vermiform appendix is visualized in the transverse section as a fixed structure with concentric layers ("target"). The internal lumen can be hypoechoic, surrounded by a zone of hyperechoic edema: a hypoechoic wall of the intestine is visualized around the edema zone. In longitudinal sections, the same structure has a tubular shape. With perforation of the appendix, an anechoic or mixed echogenicity zone can be defined near it with fuzzy contours, extending into the pelvis or elsewhere.

It is not always easy to visualize an appendix, especially if it is abscessed. Other causes of abscess in the right lower abdomen are perforation of the intestine as a result of amoebiasis, tumor or parasites. A careful comparison of the echographic picture with the clinic is necessary, but even in this case it is not always possible to diagnose with ultrasound examination.

Symptoms of gastrointestinal diseases in children

Ultrasound is very effective in the following pediatric diseases.

Hypertrophic stenosis of the pylorus

The diagnosis in most cases can be put clinically by palpation revealing the olive-like form of the pyloric thickening. It can also be easily detected and accurately diagnosed by ultrasound. As a result of the thickening of the pylorus's muscular layer, which normally does not exceed 4 mm in thickness, a hypoechoic zone will be revealed. The transverse internal diameter of the pyloric canal should not exceed 2 mm. Gastrostasis will be detected even before filling the baby's stomach with warm sweet water, which must be given to the child before further investigation.

On longitudinal sections the length of the pyloric canal of the child should not exceed 2 cm. Any excess of this size causes a strong suspicion of the presence of hypertrophic stenosis of the pylorus.

Intussusception

If the clinician suspects intussusception of the intestine, ultrasound can in some cases reveal intussusception in the form of a sausage: in the transverse sections, the presence of concentric rings of the intestine is also very characteristic of intussusception. A hypoechoic peripheral rim with a thickness of 8 mm or more with a total diameter of more than 3 cm will be determined.

In children, an ultrasound diagnosis of pyloric hypertrophy and intussusception requires certain experience and thorough clinical correlations.

Ascaridosis

The appearance of formation in any part of the intestine can take place as a result of ascariasis: while transverse scanning, typical concentric rings of the intestinal wall and of the body of the helminths contained in the lumen are visualized. Ascarids can be mobile, their movements can be observed when scanning in real time. Perforation can occur in the abdominal cavity.

Infection with the human immunodeficiency virus

HIV-infected patients often fever, but the source of infection can not always be determined by clinical methods. Ultrasound can be useful for identifying abscesses in the abdominal cavity or enlarged lymph nodes. With intestinal obstruction, overgrown loops of the small intestine with pathologically altered mucosa can be detected already in the early stages of ultrasound examination.

Ultrasound examination should include the following standard set of organ research techniques:

1. Liver.
2. Spleen.
3. Both subdiaphragm spaces.
4. The kidneys.
5. Small pelvis.
6. Any subcutaneous formation with swelling or soreness.
7. Paraorthal and pelvic lymph nodes.

When an HIV-infected patient begins to fever, ultrasound examination of the abdominal and pelvic organs is necessary.

Ultrasound examination does not help distinguish bacterial and fungal infection. In the presence of gas in the abscess, the presence of a predominantly bacterial infection is most likely, although there may be a combination of bacterial and fungal infection.