Ultrasound of inorganic retroperitoneal formations

Complex ultrasound examination of inorganic retroperitoneal formations

The retroperitoneal space is between the posterior leaf of the parietal peritoneum and the posterior wall of the abdominal cavity, which is formed by the vertebral bodies, the four lower ribs and the preperitoneal fascia, covering the diaphragm's legs, the square lumbar and iliac muscles. The upper boundary of the space is the diaphragm, the lower is the promontoryum and the nameless line, the lateral borders are the places of inflexion of the parietal peritoneum.

In the retroperitoneum, in the cellulose, stratified fascia, there are kidneys with ureters, adrenals, abdominal aorta with large branches, lower hollow vein with a number of large inflows, ascending lumbar veins, primary divisions vv. Azygos and hemiazygos, autonomic nervous plexuses, lumbar sympathetic nerve. Retrogradeal organs also include the duodenum (except for the initial section), the pancreas (except the tail). The foregoing determines the variety of clinical forms and the difference in the genesis of primary non-organic retroperitoneal tumors.

Summarizing data on the characteristics of non-organic retroperitoneal formations (NZO), it should be noted that:

1. There is no specific clinical picture of the NZO. The variety of clinical signs of the disease is due to the fact that NZOs can spread from the diaphragm to the small pelvis, and only the localization of the tumor causes the development of pathognomonic clinical symptoms.
2. The leading characteristics of the general condition are signs of tumor intoxication and weight loss. The discrepancy between the large size of the neoplasm and the small degree of its effect on the body for a long time is a characteristic feature of the NZO.

It is generally recognized that ultrasound in the B-mode is a screening method in the diagnosis of tumors of the abdominal cavity and retroperitoneal space. Based on the research data in the B-mode, you can get information about the size, shape and structure of education. Despite the fact that there are different points of view in the literature, ultrasound in B-mode provides quite definite information about the structure of individual nosological forms of NZOs, such as tumors from adipose tissue, some neurogenic formations, and teratomas.

To clarify the location of the neoplasm and the solution of the question of its resectability, V.V. Zvirkun proposed a scheme for dividing the retroperitoneal space into 5 zones, numbered in a clockwise direction:

1. between the diaphragm from above, the aorta on the left, the left renal artery from below and the lateral abdominal wall on the right;
2. between the left renal artery from above, the aorta on the left, the left iliac artery from below and the lateral abdominal wall on the right;
3. Pelvic floor - below the iliac artery and nameless line;
4. between the right common iliac artery from below, the infrarenal segment of the aorta on the right, the lateral abdominal wall to the left, and the right renal artery from above;
5. between the right renal artery from below, the suprarenal segments of the aorta on the right, the side wall to the left and the right diaphragm dome from above.

According to the US-images of the main arteries and veins, it is necessary to analyze their anatomical location and the course of the neoplasm. In this case, the anatomical course of the vessels can have the following options: unchanged, altered, or in the structure of the formation. The registration of LCS allows you to judge the status of hemodynamics in the studied vessels, taking into account the presence or absence of local changes in blood flow. So, according to Yu.A. Stepanova, among the 60 investigated NZO changes in the anatomical course of the vessels revealed in 76.7% of the observations, of which 65.9% of the patients were diagnosed with a hemodynamically significant extravasal shock of compression in this area. With recurrent tumors, changes in the anatomical course of the main vessels are possible.

Vessels enveloping the tumor are visualized only in malignant tumor genesis. The source of these vessels can be lumbar arteries. Lower hollow vein, iliac arteries and veins. Investigated vessels with a diameter of 1.5-3.0 mm are represented by arteries with collateral blood flow and veins with a monophasic blood flow spectrum. However, for tumors of large size, polycyclic and / or multinodular form, difficulties in determining the presence and recording of the anatomical course of the vessels may occur. Enveloping the tumor. In a number of cases, lumbar and iliac vessels are the source of vessels participating in the blood supply of the NZO. Using the regime of CDC and / or EHD, it is possible to trace their anatomical course to the tumor. Register the diameter (1.5-5.0 mm), as well as determine the nature and magnitude of blood flow.

Diagnosis of various variants of intratumoral angioarchitectonics is one of the interesting and poorly studied questions. When interpreting the data of angioarchitectonics, the NZO should assess the degree of their vascularization. NZOs can be hypervascular, hypo- and avascular. The degree of vascularization depends on the type, size of the tumor and the nature of its blood supply. We compared the results of a morphological study of inorganic tumors and color Doppler scan data. The data obtained by us made it possible to analyze the angioarchitectonics of various groups of retroperitoneal groups of different genesis and to reveal some of their features. Thus, an analysis of the angioarchitectonics of 80 NZOs, according to Yu.A. Stepanova, showed that the intra-tumoral blood flow is not detected in the lipoma. Liposarcoma traces the following trends: with a tumor size of less than 5.0 cm, no evidence of intratumoral blood flow has been obtained in any observation, but as the tumor increases, single arteries with a collateral type of blood flow and vein are revealed. Tumors of large sizes are predominantly hypervascular. They register a lot of arteries and veins. Recurrent tumors are usually hypervascular. The vascular network within the tumor increases with each new relapse. Apparently, it is this circumstance that can explain the absence of foci of disintegration in liposarcoma in contrast to leiomyosarcoma. Intra-tumorous network inside the leiomyosarcoma is represented by arteries and veins, however it is insignificant even at a tumor size of more than 15.0 cm. There was no intra-tumoral blood flow in hemangiomas, lymphangiomas, with systemic diseases. In malignant morphological forms, arterial and venous blood flow was diagnosed in patients with rhabdomyosarcoma, hemangiascarcoma, lymphangiosarcoma, mesenchymoma, neurosarcoma, tumors of unknown origin. The described ultrasound images at the level of tumor vessels abound in different variants, which is associated with a variety of morphological types of the tumor, different genesis and individual features of their blood supply.

Summarizing the data on the possibilities of color Doppler scanning for examination of patients with NZO, it should be emphasized that the method allows us to clarify the localization of the neoplasm and determine the relationship with the main vessels, to identify the sources and ways of supplying blood to the neoplasms; it is one of the leading methods in assessing regional anthrochitectics in zone of the NZO. Such a volume of information about the anatomical and functional state of the arteries and veins of the abdominal cavity and retroperitoneal space helps surgeons to decide the nature and extent of surgical intervention in this category of patients.

However, CDS is also inherent in the limitations: the ultrasound image of the vascular system is possible only in separate segments; in the presence of a low blood flow velocity in the vessel, it is not possible to trace its anatomical course.

Three-dimensional reconstruction of the ultrasound imaging includes a study in B-mode, ultrasound angiography and a combination of B-mode and ultrasound angiography. The use of three-dimensional reconstruction in the B-mode in the examination of patients with NZO makes it possible to obtain: a clearer image of the structural features of the studied formations due to the transparency of the image; a greater amount of information about the condition of adjacent tissues and structures due to their unification into a single visual array; advantages in assessing the marginal zone and the shape of the pathological focus.

Such information allows us to clarify the details of the structural features of the neoplasm, but the data obtained using the combination of B-mode and ultrasound angiography is of great clinical importance.

Three-dimensional reconstruction using a combination of B-mode and ultrasound angiography makes it possible to visualize the main vessels at a greater length, in some cases to trace the anatomical course, which is not determined by color Doppler scanning. Especially improves the possibility of visualization of vessels of medium and small caliber, which allows more carefully trace their anatomical course. This information is especially important in the diagnosis of vessels involved in the blood supply of the neoplasm, and the vessels surrounding it, as well as intra-tumoral vessels. Using a combination of B-mode and ultrasound angiography allows to correctly correlate the anatomical position of the vessels with respect to education and obtain a complete picture of angio-architectonics of inorganic retroperitoneal formations. Color Doppler scanning and three-dimensional reconstruction mutually complement each other, which gives grounds to offer these two methods for complex application in the ultrasound examination of patients with inorganic retroperitoneal formations.

Analyzing our material based on the results of examination of patients with NZOs using 3D reconstruction, we believe that the indication for the three-dimensional reconstruction is the specification of anatomical features and the location of the vascular system in the zone of inorganic retroperitoneal formation.

Thus, the use of the newest ultrasonic technologies - color Doppler scanning and three-dimensional reconstruction of abdominal vessels - has shown that non-invasive ultrasound diagnostics reaches a qualitatively new level that allows taking part in the choice of tactics for treating patients.