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How is a kidney ultrasound performed with a contrast agent? Ultrasound diagnostics (ultrasound) Generations of contrasts for ultrasound examination

Ultrasound is used in diagnosing a huge list of diseases (including urology and gynecology), as well as in managing pregnancy.

Unlike the X-ray method, ultrasound can be performed quite often, and this allows you to monitor the patient’s condition over time. This eliminates the risk of error in diagnosis and treatment.

Ultrasound examination is completely painless, extremely comfortable for the patient, and in 90% of cases does not require prior preparation.

Ultrasound with contrast

Contrast-enhanced ultrasound examinations appeared only in the last decade, but have already become an integral part of diagnosis. The use of a contrast agent allows you to obtain an accurate image of complex formations, disturbances in the structure of organs, vessels, cavities, etc.

Contrast ultrasound is used mainly in:

  • obstetrics;
  • angiology;
  • hepatology;
  • cardiology;
  • oncology;
  • orthopedics;
  • uronephrology.

But the high accuracy of the method suggests that in the near future contrast-enhanced ultrasound will be used in all areas of medicine.

Ultrasound during pregnancy

Ultrasound examinations are necessary both at the planning stage and during pregnancy management.

Ultrasound allows you to identify disorders that can interfere with the conception and bearing of a child. In the early stages of pregnancy - exclude ectopic pregnancy, improper attachment of the fertilized egg.

During further diagnostics, ultrasound examinations not only determine the sex of the unborn child, but also monitor its development.

Timely detection of developmental pathologies, intrauterine diseases, disorders in the urinary and reproductive systems of the mother herself allows us to avoid many risks associated with pregnancy, childbirth and the health of the unborn baby.

Modern myths

Many mothers, due to prejudice or too much pressure from the older generation, are afraid to undergo this procedure, as they believe that it can harm the child. However, many years of research have shown that ultrasound is absolutely harmless to the fetus.

The gel used during the procedure does not cause allergic reactions. It is sterile, does not penetrate into the deep subcutaneous layers and does not cause complications in inflammation of internal organs, including the uterus, ovaries and rectum.

During a transvaginal examination during pregnancy, the gel does not in any way affect the nature of fetal formation, the amount of amniotic fluid and other factors. Just as the frequency at which the ultrasound machine operates does not affect the formation of the child and in no case harms the formation of internal organs, brain, etc.

It has been proven that ultrasound is not only safe, but strictly indicated during pregnancy management.

Contraindications

Ultrasound examination should not be performed if:

  • infectious skin diseases;
  • suppuration on the surface of the epidermis and mucous membranes;
  • rashes of unknown etiology;
  • mental disorders.

You should also postpone the prescribed study if the patient experiences an exacerbation of inflammatory processes in the kidneys, ureters, and liver. At the peak of the disease, even slight pressure from the nozzle can cause severe pain.

All other contraindications are not associated with health hazards, but with low information content for diagnosing a specific disorder or the need to conduct research only during a certain period. For example, some gynecological or monological types of examinations are carried out only on the days of the cycle indicated by the doctor.

A. Martegani, MD, L. Aiani, MD.

Department of Diagnostic Imaging, Valducee Hospital, Como, Italy.

Translation of the article:"Technological advancements improve the sensitivity of CEUS diagnostics."

Contrast-enhanced ultrasound (CEUS) provides real-time imaging of the dynamics of vascularization of lesions, parenchyma, and blood vessels.

Characterization using ultrasound

Rice. 1. Solid heterogeneous focal formation in the VII segment of the liver (A). On contrast-enhanced ultrasound, the mass appears hypervascular in the arterial phase (B). In the late phase it has a washout effect (C). Corresponding arterial phase on contrast-enhanced MSCT* (D).

Final diagnosis:"hepatocellular carcinoma".
*MSCT: multi-slice computed tomography.

The use of contrast increases the diagnostic accuracy of ultrasound in the assessment of parenchymal and vascular diseases not only in the abdominal organs, but also in superficial structures.

Introduction

Contrast-enhanced ultrasound (CEUS) is based on the interaction between an echo contrast agent (UCA) and an ultrasound system with special software. The contrast agent consists of microbubbles stabilized by a membrane that allows them to persist in the bloodstream for at least 4-5 minutes. Microbubbles enhance the ultrasound signal coming from the blood. Their size, approximately corresponding to the size of red blood cells, allows them to pass through the alveolar-capillary barrier and reach the circulatory system without penetrating the endothelial barrier, even when administered intravenously, so they can be considered as a “blood depot” contrast agent.

Based on available data, echo contrast agents have a very good safety profile as adverse events, mainly allergic reactions, are rare.

Echo contrast agents were originally developed to enhance signals in the color mode and at the level of blood vessels that are too deep or in which the blood is moving too slowly.

However, the use of special algorithms at low acoustic pressure for visualization of contrast agents has made it possible to develop ultrasound techniques for studying micro- and macrovascularization of parenchymal tissues and pathological formations, as well as large vessels.

Contrast-enhanced ultrasound, as a new diagnostic method, allows one to amplify the acoustic signal from microbubbles and filter out the signal coming from surrounding static tissues, relying on the nonlinear properties of the response of the contrast agent. In this regard, this method makes it possible to detect only bubbles distributed in the blood circulation of the organ under study in real time, and thereby display microcirculation.

Recently developed technologies make it possible to use contrast-enhanced ultrasound to examine deep parenchymal tissues, superficial tissues and vascular structures in real time. Below are studies performed using convex and linear sensors and special software supported by the system (Samsung Medison Co. Ltd., Seoul, Republic of Korea).

Ultrasound with contrast for examination of the abdominal cavity, superficial structures and blood vessels

A. Evaluation and monitoring of hepatocellular carcinoma during sTACE therapy

Contrast-enhanced ultrasound demonstrates high sensitivity in detecting hypervascularization phenomena (primarily in the microvasculature) in real time, so this method plays an important role in early and long-term monitoring of cancer therapy, in particular percutaneous ablation or angiographic procedures.

Rice. 2. Solid and heterogeneous nodular formation with signs of intra- and perinodular blood flow in the mode, located in the right lobe of the liver (A). Contrast-enhanced ultrasound demonstrates intense arterial enhancement (B) with gradual and delayed washout (C) that becomes more evident in the late phase (D).


MSCT with contrast in the axial plane in the arterial phase (E) and reconstruction in the MIP-3D mode (F) reveal diagnostic features consistent with hepatocellular carcinoma.

In this particular case, contrast-enhanced ultrasound was able to identify lesions that would otherwise be unlikely to be seen on ultrasound scanning.

It helps in the management of patients after ablative procedures, in particular in the case of continued growth of tumors or relapses at the site of previously treated lesions (Fig. 2,3).

Rice. 3. Angiographic demonstration of vascularization of the neoplasm (A). Follow-up study after selective embolization (B): preservation of minimal tumor size, which receives nutrition from the blood supply from the right hepatic artery (red arrows). Below is a control ultrasound performed the next day: in B-mode (C) you can see a hyperechoic nodular formation due to the presence of air areas.


On contrast-enhanced echo (D), compared with B-mode, the mass appears largely avascular, confirming the angiographic findings of persistence of active tumor tissue in the periphery (F, G). Confirmation is on images obtained with contrast-enhanced MSCT in the arterial (H) and venous (I) phase. Diagnostic signs correspond to the state after subtotal therapy for hepatocellular carcinoma.

B. Assessment of hematogenous dissemination of metastases throughout the peritoneum

Modern technologies allow the use of contrast-enhanced ultrasound in the study of surface structures using high-frequency linear sensors.

Ultrasound with contrast showed higher sensitivity than in detecting changes in the macro- and microvasculature. This opens up the possibility of determining the solid and vascularized nature of space-occupying lesions, indicating the direction for further diagnosis (Fig. 4).


Rice. 4. Color Doppler ultrasound (A) confirms the presence of nodules in the parietal peritoneum (white arrows) and parietal pleura (yellow arrows). Associated ascites and isolated small vascular areas only in nodular formations on the pleura.




Selective study of a nodule on the peritoneum, performed with echo contrast using a high-frequency linear probe: compared with the original image (B), one can notice an intense increase in the signal in the nodule in the early arterial phase (C) and an increase in the signal from the nodule and adjacent liver parenchyma in late phase (D).


Compared with the original CT image (E), the contrast-enhanced image demonstrates enhancement (F) of the peritoneal nodule (pre-contrast, 49 Hounsfield units; post-contrast, 105 Hounsfield units).

Final diagnosis:"peritoneal carcinomatosis".

C. Examination of the internal carotid artery: occlusion or pseudo-obstruction?

Contrast-enhanced ultrasound can also be used to examine large blood vessels because it is more sensitive to slow blood flow and less affected by artifacts.

As reported in many recent publications, contrast-enhanced ultrasound allows for more accurate measurement of intima-media thickness, which is now considered an important indicator in determining the risk of cardiovascular disease, moreover, the contrast agent can help distinguish between severe carotid stenosis and pseudo-occlusion from complete occlusion, since it has a higher sensitivity to slow blood flow than the Doppler mode (Fig. 5).


Rice. 5. With B-mode ultrasound (A), a hyperechoic heterogeneous inhomogeneous echostructure is visualized in the postbulbar section of the internal carotid artery. Presence of a small calcified plaque (white arrow) adjacent to the bulbar wall of the internal carotid artery.




Color Doppler imaging (B) shows a weak signal from the vessel throughout the entire lumen of the carotid artery. On transcranial color Doppler (TCD), the Doppler spectrum of the contralateral middle cerebral artery (C) is characterized by low peak systolic velocity and low systolic-diastolic modulation, especially compared with the artery on the contralateral side (D).




Contrast-enhanced ultrasound (E-F-G) performed with a high-frequency linear transducer shows uniform lumen of the carotid artery within the bulb. The absence of contrast agent was confirmed in the postbulbar part of the internal carotid artery.

Final diagnosis: complete occlusion of the postbulbar section of the internal carotid artery.

Another option for the use of contrast-enhanced ultrasound for the carotid arteries is the study of plaques in the carotid arteries not only at the morphological, but also at the functional level, since the contrast agent can reveal the presence of vasa vasorum in plaques in real time. In a number of studies, the presence of vasa vasorum in atheromatous plaques correlates with their increased instability. Thus, contrast-enhanced ultrasound has the potential to become an important indicator of increased risk of cardiovascular disease in the near future.

Discussion

In our daily practice, we often use contrast-enhanced ultrasound to diagnose a variety of clinical cases and study various anatomical areas. The signal amplification effect that this technique provides is an important factor in planning an appropriate approach to diagnosis and treatment, as well as a comprehensive assessment of pathological features, potentially providing a comprehensive set of diagnostic tools capable of covering a wide range of anatomical structures.

Conclusion

When used correctly, contrast-enhanced ultrasound provides high sensitivity and can even produce results comparable to CT and MRI. The low invasiveness and low cost of the method are also advantages compared to other imaging methods. Given recent technological developments and the possibility of using contrast-enhanced ultrasound for superficial structures, this method may even open up prospects in the diagnosis of breast and prostate neoplasms.

Supported systems: , .

Literature

  1. EFSUMB Study: Group The EFSUMB Guidelines and Recommendations on the Clinical Practice of Contrast Enhanced Ultrasound (CEUS): update 2011 on non-hepatitis applications. Ultraschall Med. 2012; 33(1):33-59.
  2. Guidelines and good clinical practice recommendations for Contrast Enhanced Ultrasound (CEUS) in the liver - update 2012: A WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, A|UM, ASUM, FLAUS and ICUS. Ultrasound Med Biol. 2013;39(2):187-210.
  3. Meloni MF, Livraghi T, Fitce Cr Lazzaroni S, Caliada F, Perretti L: Radiofrequency ablation of liver tumors: the role of microbubble ultrasound contrast agents. Ultrasound Q. 2006;22(1):41-17.
  4. Bolondi L The appropriate location of CEUS in the diagnostic algorithm of liver lesions: a debated issue. Ultrasound Med. Biol. 2013; 39(2): 183-5.
  5. Piscaglia F, Bolondi L. The safety of Sonovues in abdominal applications: retrospective analysis of 23188 investigations. Ultrasound Med. Biol. 2006; 32 (9):1369-75.
  6. Martegani A, Aiani C Borghi C: "The use of contrast-ehnancend ultrasound in large vessels". Eur. Radiol. 2004; 14 Suppl 8:73–86.

One of the most promising research methods in radiation diagnostics today is contrast-enhanced ultrasound.

Andrey Vladimirovich Mishchenko, Doctor of Medical Sciences, Head of the Department of Radiation Diagnostics of the Federal State Budgetary Institution “National Medical Research Center of Oncology named after. N.N. Petrov" of the Russian Ministry of Health.

What is ultrasound with echo contrast? How is it different from a regular ultrasound?

In the USA and Western European countries, this technology has been widely used for more than ten years. In Russia, the first drugs for echo contrast were registered about three years ago, and since then ultrasound with contrast has been actively developing, including for the diagnosis of cancer.

Thanks to the use of contrast agents in ultrasound examinations, new opportunities have emerged. First of all, contrast-enhanced ultrasound is intended to assess vascularization, that is, blood supply to a particular organ or structure. Increased vascularization is one of the signs of malignant neoplasms.

If previously vascularization could be judged only on the basis of Doppler studies, now at the primary stage of differential diagnosis we can, based on the nature of vascularization, assume the benign or malignant nature of the changes, and understand whether there is a blood supply to the pathological tissue. Ultrasound with EC is extremely important and effective for identifying vascularized areas, when with a regular ultrasound there is tissue, but it is impossible to say whether this tissue is growing, blood-supplied, or fibrous (poorly supplied with blood - a scar).

Echo contrast is very helpful in determining the extent of damage to the tumor process.

Ultrasound with echo contrast allows you to find answers to many other questions without resorting to other methods of radiation diagnostics: CT, MRI, PET-CT - high-tech, but also having a certain harmful effect on humans due to X-ray, gamma radiation, nephrotoxic contrast agents.

The pictures clearly show the difference from a conventional ultrasound:

The echo contrast mode (left) allows you to clearly localize focal liver damage.

In echo contrast mode (left), metastases in the liver are clearly visible.

What echo contrast agents are used for ultrasound?

This is a non-toxic drug, completely inert for humans. This is a white powder that, when mixed with saline, forms microbubbles of air, which dissolve and are then excreted through the lungs. If necessary, contrast-enhanced ultrasound can be performed frequently. During its use throughout the world, no side effects have been reported.

Computed tomography (CT) or magnetic resonance imaging (MRI) has traditionally been used for contrast. The contrast agent used in CT or MRI shows both vascular structures and their permeability. Accordingly, in the image it is difficult for a specialist to understand whether there are so many vessels in the tissue or whether they are so easily permeable.

The drug used in contrast-enhanced ultrasound differs from those used in CT or MRI. In ultrasound with echo contrast, the “glow” of the drug occurs only due to the vascular bed because microbubbles do not go beyond the vascular wall and do not penetrate the interstitium (the intercellular space that forms the skeleton of most tissues).

The diagnostician clearly understands that microcirculatory vessels are present here in a very high concentration. Most often, a tumor differs in structure from a normal organ precisely in its vascular bed: either it is a low concentration of vessels per area, or, conversely, it is high.

Who determines the appropriateness of using contrast?

The study is usually prescribed by a radiologist and ultrasound diagnostician who first encounter the patient.

Thanks to the scientific literature, conferences and schools on radiation diagnostics, which are conducted by specialists from our department, more and more oncologists understand the promise and advantages of this technology, and the oncologist at the initial appointment can already recommend doing an ultrasound with echo contrast, realizing that the situation is complex and it can only be resolved with echo contrast.

More often, during an ultrasound examination, the doctor decides whether it is necessary to continue and upgrade the scanning technique to the use of echo contrast, or whether he has already received all the necessary information. At the same time, the ultrasound diagnostic doctor must be an expert, understand the essence of the ongoing pathological processes and, in conclusion, try to answer all the questions necessary for the oncologist to make decisions on treatment. That is, often a person is scheduled for a “simple ultrasound”, and a specialist determines whether there is a need to do an ultrasound with contrast.

How long does it take to see a patient during ultrasound with EC?

A standard ultrasound appointment takes no more than 20 minutes per scanning area. Formally, contrast slightly increases the reception time by another 5-10 minutes. More often it is necessary to prepare the room for the injection of a contrast agent, so the patient is asked to wait. An ultrasound specialist spends most of his time on special calculations and analysis of images without the patient.

Echo contrast is a complex procedure that requires special equipment and skills. Gas microbubbles should form inside the solution; you need to prepare a special solution with them, make sure that they do not collapse, carefully store and administer.


For what diseases is this research technique particularly effective?

The contrast technique in oncological practice is used for lesions of various areas: the liver, kidneys and bladder, lymph nodes, thyroid and mammary glands, uterus, ovaries, soft tissue tumors; there is also information about the successful use of echo contrast in the study of the prostate and pancreas. These studies are also carried out in full at the N.N. Petrov National Medical Research Center for Oncology.

Ultrasound in gynecology is used less frequently than in other areas. We approach new technologies carefully. Before using it in routine practice, we spent about a year accumulating our research experience, and also carefully studied the achievements of European and American specialists. With the help of ultrasound with EC, we check cases already known to us and thus can evaluate the effectiveness of the new technique. Now at the National Medical Research Center of Oncology named after. N.N. Petrov performs an ultrasound examination with contrast enhancement of the cervix, as well as the ovaries and uterine body for the purpose of differential diagnosis and assessment of the prevalence of tumors.

Please tell us what are the areas of application and prospects for the development of this technique in oncology.

Application areas of contrast-enhanced ultrasound:

  1. Diagnostics
    • Polycontrast properties (ultrasound, MRI nanoparticles, MR spectroscopy for phosphorus, fluorescent endo-microscopy)
    • Tumor imaging
      • vascularization
      • assessment of prevalence (invasion of blood vessels, other organs and structures)
      • lymph node damage
    • Quantitative assessment of the effectiveness of antitumor therapy
    • Evaluation of ablative treatments and embolization
    • Specialized
      • EUS
      • intraoperative ultrasound
  2. Treatment
    • Targeted delivery of drugs and metabolites
    • Strengthening the HIFU effect

Today, the use of ultrasound with echo contrast is very important and effective for diagnosing a tumor, assessing the response to treatment, the effectiveness of antitumor therapy - both classical: surgical, radiation and chemotherapy, and experimental minimally invasive - ablation (cryo-, laser-, radiofrequency, high-intensity ultrasound etc.)

The issues of tomorrow are the use of microbubble solutions in the treatment of oncological diseases - targeted delivery of drugs and metabolites, enhancing the HIFU effect. HIFU therapy is a new generation technology that uses the energy of ultrasonic vibrations to treat deep-lying tissues.

Another promising property of microbubble solutions is their potential to be visible using any radiation diagnostic methods (CT, MRI, radionuclide diagnostics). Perhaps this will also be implemented in the future.

Until recently, ultrasound was the only method of examination that did not consider the use of contrast agents. Color Doppler ultrasound was considered a unique non-invasive technique for studying blood vessels. With the introduction of ultrasound examinations of contrast agents into practice, it became possible to study the vascular pattern, evaluate its nature, trace the phases of accumulation and elimination of contrast agents, and study hemodynamics. In fact, a definite alternative to contrast computed x-ray tomography has emerged.

A.V. Zubarev, S.V. Salnikova, A.A. Fedorova, A.V. Ganina, S.O. Churkina, A.P. Norkina

Kremlin Medicine Clinical Bulletin No. 3/2017

Introduction.

Microbubble suspensions are used as a contrast agent for echocontrast of the kidneys, which are obtained by intravenous injection of special gas-forming drugs into the patient’s blood. The size of microbubbles does not exceed the size of a red blood cell and is completely harmless to the patient. In addition, they do not cause allergic reactions in the body; they do not have the nephrotoxicity characteristic of radiocontrast drugs. Microbubbles interact with the ultrasound signal and begin to resonate and burst, providing contrast to vessels and organs of different morphological structures.
Today, echo contrast agents are being actively introduced into everyday practice and are increasingly used by ultrasound doctors, providing the opportunity to conduct contrast enhancement similar to contrast enhancement techniques for CT and MRI. At the same time, the possibilities of echo contrast in diagnosing kidney diseases are still little known to our clinicians. This is probably why they more often refer their patients to competing highly informative and expensive imaging methods, for example, CT or MRI, which allow for a comprehensive assessment of the morphology and function of the kidneys. However, it is important to recall that CT examination of the kidneys is burdened by radiation exposure and nephrotoxicity of the iodine radiocontrast agent [7].
We made an attempt to use our own clinical material to show the possibilities of echo contrast in the diagnosis of various pathological conditions of the kidneys.

Materials and methods:

During the period from May 2016 to April 2017, we performed echo contrast of the kidneys in 27 patients. The criterion for selecting patients for echo contrast was the presence of changes in the structure and function of the kidneys, visualized by standard ultrasound of the kidneys. Before administration of the echo contrast agent, informed consent was obtained from each patient according to the approved protocol. The age of the examined patients ranged from 31 to 64 years, with an average of 47 years. In 13 patients, cystic formations of the kidneys were suspected, in 7 - pyelonephritis, and in another 7 - large solid formations of unknown, presumably malignant origin. Computed tomography and magnetic resonance imaging results were available in 23 patients; 15 patients underwent subsequent pathological examination after surgical interventions.

During a routine renal ultrasound examination using gray scale and ultrasound angiography techniques, we assessed the presence of pathological changes in the structure and function of the kidneys. After this, the area of ​​interest was identified. Trying not to move the sensor from the area of ​​interest, we activated the dual screen format on the ultrasound scanner. In dual-screen mode on the ultrasound machine, the contrast-enhanced image of the kidney was displayed parallel and simultaneously with the corresponding B-mode image of the kidney.

If there is a space-occupying lesion in the kidney, echo contrast allows one to study the nature of the vascular pattern, evaluate the different phases of contrast, and identify areas of destruction or disintegration of organ tissue or tumor.

To prevent rapid destruction of microbubbles during scanning, we used low mechanical index (MI) values< 0.1). После внутривенного введения 2-4 мл эхоконтрастного препарата (Соновью) согласно инструкции производителя, в режиме реального времени, мы пошагово фиксировали контрастирование сосудов и паренхимы почки. Центральный эхо-комплекс почки (мозговое вещество) контрастировался в первую очередь, затем контрастное вещество проникало в пирамидки почки. Удовлетворительное контрастное усиление длится в течение 2-5 минут, затем концентрация контрастного вещества постепенно уменьшается и в течении 6-9 минут практически исчезает.

During the ultrasound examination, we recorded video clips at various time intervals of kidney contrast. If necessary, another additional dose of echo contrast agent was repeated.

There were no adverse reactions to the administration of the echocontrast drug in any of the patients we examined.

Results and discussion.

When echocontrasting the kidneys, we obtained all the same phases of contrast enhancement as with X-ray or magnetic resonance contrast. The arterial phase with echocontrast of the kidneys is much shorter than with CT and lasts only a few seconds. This depends on the speed of administration and which arm the drug was injected into. After approximately 15-20 seconds from the start of administration, the cortico-medullary phase was recorded, gradually turning into the parenchymal phase. The parenchymal phase can last several minutes. After 5-8 minutes, microbubbles of the contrast agent are destroyed and the vessels and kidney tissue cease to contrast. It should be especially noted that a feature of echo contrast of the kidneys is the unique ability to repeat all phases of contrast anew many times, using the technical capabilities of ultrasound scanning - the so-called flashes or a powerful pulse of an ultrasonic shock wave that destroys microbubbles. This makes it possible to repeatedly assess perfusion in different areas of the renal cortex.

The presence of contrast enhancement (accumulation of microbubbles) directly in the formation itself, its septa or walls was regarded by us as a suspicion of neoplastic changes. At the same time, benign and malignant renal formations demonstrated different types of contrast enhancement. Malignant tumors are characterized by rapid accumulation of the contrast agent in the tumor and the presence of a disorganized vascular pattern in it. In all 7 patients with renal masses of solid echostructure, we obtained rapid early accumulation of the contrast agent. The presence of a disorganized, enriched vascular pattern in the formation was also noted, which also indicated a malignant tumor. Ultrasound data with echo contrast completely coincided with CT data in all patients in this group.

The presence of early contrasting of a formation or individual structures in the formation itself is an important diagnostic sign, especially when it comes to cystic kidney cancer. In a group of 13 patients with cystic kidney formations, various echo contrast options were identified. If we take as a basis the classification of cysts according to Bosniak (I-IV), generally accepted for X-ray contrast CT, then we can notice the correspondence of X-ray and ultrasound data.

This correspondence allowed us to compare CT and ultrasound data and make a differential diagnosis between benign and malignant kidney lesions based on the types of echo contrast we identified. Thus, in the cystic form of kidney cancer, contrasting of the cyst walls, internal septa or septa is observed. We consider this an important diagnostic criterion for malignant lesions, which should be relied upon when echocontrasting the kidneys. Based on the criteria we identified, in 3 cases cystic kidney cancer (Bosniak III-IV) was suspected and confirmed after surgery. A total of 10 patients in this group underwent computed tomography with contrast. In 3 out of 10 cases, CT scanning with contrast was impossible due to the high risk of allergic reactions. In 8 cases, the results of CT and ultrasound with echo contrast completely coincided. In 2 patients, CT scan showed no contrast enhancement of the cyst walls and septa, whereas with echo contrast we obtained contrast enhancement of the septa. In both of these cases, the diagnosis of cystic kidney cancer was confirmed after surgery. It must be recognized that some minimal contrasting of septa with microbubbles and their migration into the intraseptal components is rare, but can also occur with benign cystic formations of the kidneys. In our study, migration of single contrast microbubbles into the septa of benign cystic formations was observed in 2 cases.

It is well known that ultrasound is the first-line method in diagnosing most kidney diseases. In addition to successfully solving diagnostic problems using echo contrast in differentiating simple renal cysts and cystic-solid tumors, already at the first stage of instrumental examination, assessing perfusion in acute and chronic inflammatory lesions can be extremely useful. Echocontrast helps to identify the presence of areas of renal parenchyma ischemia, inflammatory and traumatic damage hidden by standard ultrasound.

The ultrasound data were fully confirmed by the results of contrast-enhanced CT. Subsequently, during conservative management of the patient, we monitored the condition of the affected renal parenchyma only using ultrasound guidance. Before discharge, a control CT study was performed, which showed almost complete restoration of perfusion in the affected kidney, which corresponded to clinical recovery. However, after echo contrast performed using Fusion technology, i.e. When CT and ultrasound data are synchronously compared, we found that with echo contrast, a small area of ​​perfusion that has not yet been fully restored remains along the periphery of the left kidney. It was necessary to extend the treatment, and we carried out further monitoring of the restoration of perfusion of this kidney only using the ultrasound method. In the group with destructive-inflammatory kidney diseases, echo contrast 6 is an alternative to CT due to the possibility of multiple dynamic repetitions. Using fusion technology, we successfully monitored 3 patients with destructive-inflammatory kidney diseases, when contrast-enhanced CT data completely correlated with echo-contrast ultrasound data.

In our study, we were able to confirm the results of other authors that echo contrast allows us to assess microvascular blood flow in the kidney, identify areas of inflammation and destruction in the renal parenchyma, detect foci of neovascularization, assess general and local vascularization of the parenchyma, based on differences in perfusion characteristics, and differentiate between solid tumors kidneys and pseudotumor formations, as well as between cystic and solid structures, although it has its limitations in characterizing “complex” renal cysts.

General limitations of the ultrasound method include difficulties in visualizing the kidneys due to their deep location and shielding of the kidney by gas from the intestinal contents.

Among the shortcomings of our study, the following can be identified: a relatively small number of observations; not all observations had a comparison with pathomorphological data of postoperative material and with CT data.

Thus, we can conclude that Contrast echography of the kidneys is not inferior in information content to contrast CT of the kidneys, and in some cases, for example, with complex cystic formations, it is superior to CT. Echocontrast of the kidneys should be included in the diagnostic algorithm for studying patients with various renal pathologies already at the first stage of instrumental diagnostics. Taking into account such advantages of the technique as the absence of radiation exposure and the absence of nephrotoxicity of the echo contrast agent used, it can be considered as the technique of choice.

List of used literature.

    A.V. Zubarev, V.E. Gazhonova. Diagnostic ultrasound. Uronephrology. Practical guide. 2002 pp. 8-22 [Zubarev A.V., Gazhonova V.E. Diagnostic ultrasound. Uronefrology. Practical guide. 2002 pp. 8-22. In Russian.]

  1. < >visualization. 2015;(1):94-114. )