Ultrasound of the visceral arteries of the aorta

Unpaired visceral arteries

As the practical activity showed, color Doppler scanning has high informative value in assessing the condition of the superior mesenteric artery, celiac trunk, hepatic (PA) and splenic artery (CA). This creates the prerequisites for expanding the methodological possibilities and, in particular, studying the question of ultrasound anatomy of the extra- and intraorgan organisms of the spleen.

The technology of investigation of the splenic artery and vein in the regime of the spleen artery and / or EDC in the area of the spleen gates assumes oblique scanning in the region of the left hypochondrium at the patient's position on the back, through the intercostal spaces in the patient's position on the right side or from the back. Performing ultrasound, it is necessary to obtain an image of the spleen along the long axis of the organ, the spleen and splenic vessels. Splenic artery and vein are located side by side, while the vein lies somewhat anterior to the artery. Not reaching the gate of the spleen, the trunk of the CA is divided into two, less often - into three branches. These are branches of the splenic artery of the first order, or zonal arteries.

Theoretically, the ultrasound image of the spleen along its long axis is divided at the gate level into two halves - the upper and the lower. The anatomical course of one artery of the first order is directed toward the upper half of the spleen, the second artery to the lower half. Tracing the anatomical course of the branches of the first order in the distal direction, it is clear how these vessels reach the parenchyma of the spleen. In the organ parenchyma, each branch of the first order is divided into two branches - segmental arteries. In turn, each segmentary artery is divided into two branches, etc. The division of the intraorganic branches of the splenic artery is, in the main, a successive dichotomous character. Of the two segmental arteries of the upper half of the spleen, a is located laterally. Polaris superior, medially. Terminalis superior. Similarly, in the lower half of the spleen - a. Polaris inferior and - a. Terminalis inferior. A. Terminalis media is located in the parenchyma at the level of the spleen gate. A qualitative evaluation of the angioarchitectonics of the spleen parenchyma indicates that most of the vessels are located and branched in close proximity to the spleen gates, to the inner and the front surface of the spleen, and small branches are directed to the outer surface of the spleen.

An area for determining the vascular zones of the spleen can serve as zone extraorganic vessels. The anatomical distribution of segmental arteries underlies segmental division of the spleen. V.P. Shmelev and N.S. Korotkevich is considered to be a zone that is fed by an arterial branch of the first order. Accordingly, there may be 2-3 zones of the spleen, the shape of which resembles a 3-4-faceted pyramid. The segment is considered to be a morphologically distinct area of the organ tissue, fed by a second-order arterial branch. The number of segments depends on the anatomical variation of the division of branches of the first order and is from 2 to 5. According to A.D. Khrustaleva, the main trunk of the splenic artery in 66.6% of cases is divided into two main branches, in 15.9% - into three main branches, and in other cases branches may be larger. According to our data, when studying UZ-anatomy of the splenic artery in 15 practically healthy people aged 25 to 40 years, the splenic artery was divided into 2 zonal arteries in 73.3% of cases, by 3-26.7% of observations. Each zonal branch in the parenchyma of the spleen was divided into 2 segmental arteries. The diameter of the splenic artery was 4.6-5.7 mm, the peak systolic velocity (PSS) was 60-80 cm / s, the average speed was 18-25 cm / s. The diameter of the zonal branches in the DCM and / or EHD regime is 3-4 mm, the PSS is 30-40 cm / s, the segmental branches are 1.5-2 mm, the PSS is 20-30 cm / s, respectively.

The study of hematological and immunological parameters after splenectomy and organ-preserving surgeries made it possible to show the advantage of saving surgery. The study of ultrasound anatomy of the zonal and segmental branches of the splenic artery is of great practical importance. Knowledge of the principles of distribution of internal spleen vessels enables the surgeon to choose the most acceptable and anatomically justified method of saving operation in case of spleen involvement.

Occlusive lesions of the visceral arteries have characteristic features. The process extends to the visceral arteries for 1-2 cm from the mouth, with non-specific aorto-arteritis - in the form of a hypertrophied wall, with atherosclerosis - determine a locally located plaque that can pass from the aortic wall. The inferior mesenteric artery is involved in the process with nonspecific aortoarteriitis seldom and usually participates in blood flow compensation.

Regardless of the cause leading to narrowing of the artery lumen, with stenosis of more than 60%, a local increase in LSC is observed in combination with changes in the spectral characteristics of the blood flow acquiring a turbulent nature, which is confirmed by data from the analysis of the spectrum of Doppler frequency shift and the change in staining of the lumen of the vessel in the DSC regime. With a stenosis of 70% or more, the systolic speed in the BWA is 275 cm / s or more, the diastolic velocity is 45 cm / s or more, in the celiac stem - 200 cm / s and 55 cm / s and more, respectively.

In case of occlusion of the visceral arteries, the lumen of the vessel does not stain and LCS is not recorded. With occlusion of the celiac trunk, an inverse blood flow (retrograde) can be detected in the gastroduodenal or common hepatic arteries. The sensitivity of the DSA method in diagnosing stenosis is 50% or more, or the occlusion of the superior mesenteric artery is 89-100%, specificity is 91-96%, for the trunk - 87-93% and 80-100%, respectively. With hemodynamically insignificant stenosis, the informativity of the spectrum of the Doppler shift of frequencies is significantly reduced. The most difficult diagnosis of hemodynamically insignificant changes in nonspecific aortoarteritis, in particular, it is difficult to assess the condition of the wall. We introduced the technique of three-dimensional reconstruction of unpaired visceral arteries into clinical practice, which widened the range of diagnostic capabilities of ultrasound diagnostics.

The three-dimensional reconstruction program includes studies in B-mode, ultrasound angiography and combination of B-mode and ultrasound angiography. As experience accumulates in the study of this contingent of patients, we believe that the results of a study in B-mode are more informative. Due to the transparency of the image of the wall and the lumen of the vessel, structural features and the contour of the wall are more clearly recorded. Comparison of the capabilities of color Doppler scanning and 3D reconstruction showed that 3D reconstruction is more informative in determining changes in wall echogenicity. A qualitative analysis of the three-dimensional image makes it possible to estimate the wall thickness. However, it should be noted that the current three-dimensional reconstruction program does not allow for a quantitative assessment of the structures under study, and also does not provide information on the status of hemodynamics. Consequently, in the diagnosis of changes characteristic of non-specific aorto-arteritis, these two methods complement each other, which makes it possible to offer them for complex application. Indication for a three-dimensional reconstruction of the visceral arteries is the presence of II or III variants of lesions of the thoracoabdominal aorta with nonspecific aortoarteriitis.

One of the reasons for the violation of hemodynamics in the celiac trunk (ES) is extravasal compression, caused by compression of the mid-arch diaphragm. Criteria for hemodynamics of significant compression of ES are: angular deformity of the artery in the cranial direction; increase in systolic velocity by 80.2 + 7.5% and diastolic rate by 113.2 ± 6.7%; a decrease in the level of peripheral resistance, confirmed by a decrease in the values of the ripple index (PI) by 60.4 ± 5.5% and the index of peripheral resistance (IPA) by 29.1 ± 3.5%; decrease in blood flow velocity and peripheral resistance indices in the splenic artery (systolic - by 49.8 ± 8.6%, IP - by 57.3 ± 5.4%, IPS - by 31.3 ± 3.1%.

Diseases of the abdominal cavity can lead to a violation of hemodynamics as a type of local or diffuse changes in the visceral arteries and their branches. Thus, with extravasal compression (EVC) or sprouting of the celiac trunk, hepatic artery with enlarged lymph nodes, volume formations of the liver, pancreas with a decrease in the lumen of the vessel more than 60%, local changes in blood flow are recorded. According to our data, with cholangiocellular carcinoma, extravasal compression of the hepatic artery was diagnosed in 33% of cases, which is probably due to the infiltrating nature of tumor growth. In patients with hepatocellular carcinoma, ES and PA were suppressed in 21% of cases, VBA - in 7% of cases. Simultaneous compression of ES and PA was noted in 14% of cases. Out of 55 patients with secondary liver tumors, the hemodynamically significant EVC of the celiac trunk was diagnosed in 1.8% of cases, and the own hepatic artery (SPA) in 4.6% of cases. Germination of spa branches was noted in 4.6% of cases. In pancreatic cancer, the superior mesenteric artery, the ES and its branches are involved in the process in the late stages of the disease. Signs EVK were detected in 39% of cases, thrombosis or sprouting of arteries - in 9.3% of cases.

The presence of voluminous formations of the abdominal cavity organs or inflammatory genesis causes a diffuse increase in the rate of blood flow in the artery, which directly participates in the blood supply of this organ. Thus, during the acute phase of hepatitis, an increase in systolic and diastolic blood flow in the PA was recorded. In a study of 63 patients with ulcerative colitis, Crohn's disease, during an exacerbation of the process, an increase in systolic and diastolic blood flow in the NBA was noted in combination with a decrease in the IPS. During the remission, hemodynamic parameters returned to normal. According to our data, in hepatocellular cancer, metastatic liver damage, a statistically significant increase in diameter values and an increase in blood flow velocity in the celiac trunk and hepatic artery are recorded.