Ultrasonography of kidney and ureter

Where to make an ultrasound of the kidneys and how to properly prepare for this study, we will consider these issues more detailed. An ultrasound study of the kidneys refers to a complex of diagnosis of the urinary system and is considered an effective and safe method for identifying pathologies. The procedure itself is small-invasive and provides complete information about the size, shape and location of the kidneys. Ultrasonic waves visualize the kidney, so that the blood supply and the structure of the organ can be assessed.

To carry out the procedure, the patient goes to the couch on the side, a special gel is applied to the skin and an examination is carried out using the sensor. The main indications for an ultrasound of the kidneys are: infectious and inflammatory diseases, preventive examinations and monitoring of organs after diseases or surgical intervention. Diseases of the endocrine system, changes in the functioning of the kidneys, abnormal urine tests, lumbar pain and many other symptoms, are an indication for ultrasound.

Indications for ultrasound of the kidneys and ureters

1. Pain in the kidneys or along the ureters.
2. Suspicion on the renal tumor (large kidney).
3. Non-functioning, according to urography, kidney.
4. Hematuria.

Indications for ultrasound of the kidneys and ureters

Preparation for ultrasound of the kidneys and ureters

1. Port preparation. Preparation is not required. If it is necessary to study the bladder, then the patient should drink water.
2. Patient position. Start examination in the patient's position on the back. Apply the gel arbitrarily on the upper right side of the abdomen.
3. The choice of the sensor. Use a 3.5 MHz sensor for adults, a 5 MHz sensor for children and thin adults.
4. Installing the level of the necessary sensitivity. Start the study by placing the sensor in the right upper abdomen. Tilt the sensor and adjust the sensitivity so as to get the optimal image of the renal parenchyma.

Preparation for an ultrasound of the kidneys and ureters

The ultrasound of any organ should be polypital, i.e. Scanning should be carried out with all surfaces available for ultrasonic visualization.

The study of the kidneys begins in the lumbar region, scanning them from behind in the longitudinal direction. Then the sensor is moved to the lateral and front surface of the abdominal wall. After that, a series of transverse and slanting sections is carried out in the same departments, determining topography, size, condition of the parenchyma, kidney sinus and cup-lobe system (CHLS).

At the same time, they pay attention to the contour of the renal parenchyma, its thickness, homogeneity, the presence or absence of visualization of the cup-lobe system and pathological formations, the size of the renal sinus, as well as on the mobility of the kidney during breathing.

The right kidney is visualized in the patient's position on the back, while the liver is used as an acoustic window.

Scanning is always carried out with a hold of breathing on a deep breath: ask the patient to take a deep breath and hold his breath. Do not forget to say that the patient relaxes and breathes normally after that.

Methods of conducting an ultrasound of the kidneys and ureters

A normal kidney on longitudinal sections is the formation of a bean-shaped shape with a clear, even external contour created by a fibrous capsule, in the form of a thin (up to 1.5 mm) hyperechogenic tissue layer between paranephrium and parenchyma. Parenchyma of the kidney is a tissue of a homogeneous echostructure and usually reduced echophage (hypoechogenic). Normally, its thickness is about 1.5-2.0 cm. Its inner part borders on the kidney sinus and has a somewhat uneven contour due to papillae protruding into the sinus. Sometimes, especially in young people, in the renal parenchyma, triangular pyramids are visible, facing the base to the outer contour of the kidney, and the top of the sinus, forming the papillae. The pyramids have even lower echophage than parenchyma. The echogenicity of the renal sinus is similar to such paranephral tissue. It is located in the center of the kidney and is surrounded by parenchym during longitudinal echoscania. With echography of a normal kidney, only some vascular bundles can be visualized in it. The cup-lobe system is not determined normally. In the study of patients with water load or with a filled with bladder, a pelvis is visualized in the form of anemic formation. Its anteroposterior size should not exceed 1.0-1.5 cm. The kidney vessels are usually visible with a transverse or spit scanning from the front abdominal wall.

Normally, when breathing, the mobility of the kidney is 2-3 cm. Paranephral tissue has a homogeneous echostructure. increased echogenicity compared to renal tissue; It does not have pathological formations.

Ultrasound attach great importance in the differential diagnosis of volumetric formations of the kidneys. In this case, the tumor emanating from the kidney parenchyma is defined as a rounded or oval formation, different in echo. On this basis, all tumors can be divided into two large groups: solid (dense) and liquid. Echostructure can be homogeneous and heterogeneous. Depending on the form of growth and localization, the tumor can be extrarenal (changes the size and contour of the kidney), intrarenal (located in the sinus, deforms it) or mixed. With a large tumor. occupying the entire kidney, the renal sinus may not be determined. With the displacement and compression of the cup-lobe system, its dilatation is possible.

The diagnostic reliability of ultrasound with kidney neoplasms reaches 97.3%.

If a volumetric formation in the kidney is detected, its character is primarily established (dense or liquid).

The measurements taken during an ultrasound study are mainly of smaller values than the same parameters obtained by radiography: they are more accurate.

Both kidneys should have approximately the same dimensions in adults, the difference between the lengths of the kidneys by more than 2 cm is pathological.

Ultrasound signs of a normal kidney and ureters

If any kidney is not visualized, then repeat the study. Adjust the sensitivity for the clear visualization of the parenchyma of the liver and spleen and scan in various projections. Determine the size of the visualized kidney. The kidney hypertrophy occurs (at any age) a few months after removing the other kidney or stopping its functioning. If there is only one large kidney, and the second is not detected even with the most thorough search, then it is possible that the patient has only one kidney.

Of all the dense (echopositive) neoplasms, the kidneys are considered the most common renal cancer (according to different authors, from 85 to 96%). 5 to 9% are benign tumors (oncocytoma, angiomyolipom, adenoma, leiomiom, etc.).

It should be emphasized that it is impossible to judge the morphological structure of the tumor on the basis of the non-orphological methods of the study, which include ultrasound.

If dense (solid) formation of a kidney is detected, the echogenicity of which may be lower, higher or approach the latter, pay attention to its contours and homogeneity. So. With kidney cancer, the formation of heterogeneous echostructure is found with alternating areas of reduced and increased echophage. Often, such formations contain echoneagal (liquid) inclusions due to hemorrhages and necrosis. On echograms, the absence of the effect of enhancing the reflected ultrasound waves (unlike liquid formations) or their weakening on the distal border of the tumor and underlying tissues is determined. The outer contour of the multi-sized formation is usually uneven, and with invasion into adjacent fabrics - fuzzy. However, it should be borne in mind that a similar echostructure is determined with xanthogranulomatosis pyelonephritis, benign kidney tumors and fibrous-cave-free tuberculosis.

Of all the solid benign tumors, the kidneys are the most characteristic ultrasonic picture by angiomyolipom and lipoma, which on echograms look like increased echogenicity homogeneous formations, similar to this basis with paranephral (fat) fiber. However, more accurate methods used for the differential diagnosis of solid kidney formations found for ultrasound are computed tomography (CT) and MRI.

If an anekhogenic formation in the kidney is found, attention is also paid to the homogeneity of its echostructure. The cyst is characterized by a homogeneous anekhogenic contents, even contours, the lack of internal structures, and the strengthening of the reflected ultrasound waves on the distal border. Internal structures in the liquid environment of education can indicate a malignant process (sarcoma, cystic version of kidney cancer, tumor in a cyst) or such pathological conditions as a hematoma, echinococcosis, kidney abscess, tuberculosis cavity.

In doubt in the dense or liquid nature of the formation, to clarify the diagnosis, CT with contrast, MRI or puncture under ultrasound control, followed by cytological examination of the resulting fluid and cystography, is performed. If the liquid is not obtained with puncture, then the solid structure of education can be assumed and its biopsy can be performed.

Quite often, especially with a small size, the neoplasm in its acoustic properties practically does not differ from the normal parenchyma. That is why the closest attention with ultrasound should be paid to the irregularities of the renal contour, deformations of the renal sinus, and the thickening of the parenchyma. The minimum size of the tumor of the renal parenchyma, which can significantly be detected during echography of 2 cm. When forming small sizes, differential diagnostics with an additional slice of the renal parenchyma (especially the “humpbacked” kidney) is often necessary. If an ultrasound is suspicious of such an education, then to clarify the diagnosis, multi-spiral CT (MSCT) with contrast is used, the information content of which is much higher (especially with small formations) and approaches 100%.

Along with the detection of a tumor, echography allows you to obtain valuable information about the prevalence of the process. In addition to signs of germination into neighboring organs, it is possible to diagnose tumor thrombosis of the renal and lower vengee of veins, increased regional lymph nodes located paraaortically, paracaval and in the arthocaval gap, but more informative methods for determining the stage of the disease are considered CT and MRI.

With the introduction of ultrasound in medicine, the frequency of detection of kidney cancer (especially asymptomatic forms) has significantly increased. This is due to the use of this method as a screening test for preventive examinations of the population. The asymptomatic course of kidney cancer and its random detection with ultrasound are observed in more than 54% of patients.

Ultrasound diagnosis of papillary tumors of the Navy is extremely difficult. With a small size of the papillary tumor of a pelvis that does not violate the outflow of urine from the cup-lobe system, the echographic picture of the kidney may not differ from normal. The tumors of the cup-lobe system look mainly as hypoechoic formations of irregular shape in the sinus of the kidney. They can easily be taken for an expanded cup or cyst of renal sinus.

It is sometimes possible to detect and differentiate such a tumor only against the background of the expansion of the cup-lobe system (in case of violation of the outflow of urine) or with the help of artificially created polyuria.

If the tumor of the cup-lobe system infiltrates the renal leg or sprouts into the organ tissue, then its detection with conventional ultrasound is simplified, but in this situation it is necessary to verify it from the tumor of the renal parenchyma.

The ureter with conventional ultrasound is not determined. Only with significant expansion, partial visualization in the upper and lower third is possible. Therefore, diagnosis using the usual non-invasive ultrasound of the papillary formations of the ureter is impossible. A new invasive method developed in recent years - endoluminal echography - allows you to obtain a high-quality image of the Navy throughout and with great accuracy to diagnose any violations of their structure (including tumors). The essence of the method is to conduct a miniature ultrasonic sensor mounted in a flexible probe, retrograde along the urinary tract. In addition to detecting a tumor and determining the nature of its growth, this method allows you to determine the prevalence and degree of tumor invasion into the wall of the urinary tract and surrounding tissues, which is of great importance in determining the stage of the disease.

Ultrasound plays an important role in the complex diagnosis of inflammatory processes of urinary tract. So, in acute pyelonephritis, by the presence or absence of visualization of the cup-lobe system, the character of pyelonephritis (obstructive or non-constructive) is established. Ultrasound also allows you to detect edema of paranephral tissue, which manifests not only the restriction of respiratory mobility of the affected kidney, but also a kind of halo of rarefaction around it. Karbunkul of the kidneys - the formation of low echo seences with clumsy and not always even contours. Its internal structure can be heterogeneous, sometimes with small echopositive inclusions. With purulent contents, the formation will be almost anechogenous. At the location of the carbuncle, the kidney contour can be uneven and whip. His echographic picture should be differentiated from such a tuberculosis cavity. The latter has a dense echopositive capsule and more dense internal inclusions - calcification (up to petrifers), which look like hyperechogenic formations with a clear acoustic path.

In the initial stages of chronic pyelonephritis, the ultrasound does not allow to detect any reliable signs of the disease. With a far-reaching inflammatory process, a significant decrease in its size with a relative increase in the area of renal sinus structures in relation to parenchyma is noted with the outcome of the kidney. The latter acquires a heterogeneous structure, uneven contours and a thickened capsule.

In the final stages of inflammation (pionefrosis), an increase in the kidney, thickening of its capsule, compaction of the surrounding paranephral tissue can be detected, often limiting the mobility of the affected kidney, a decrease in the thickness of the parenchyma with the expansion and uneven contours of cups and pelvis, the walls of which, due to cicatricial changes, acquire increased echogenicity. In their lumen, it is possible to visualize a heterogeneous suspension (pus and necrotic tissues) and echopositive formations with acoustic shadow (calculi).

Ultrasound provides significant assistance in the diagnosis of paranephral abscess and purulent changes in the fiber of retroperitoneal space. Typically, the abscess is located in the immediate vicinity of the kidney and looks like an echonegative formation of an oval shape, almost completely devoid of internal structures. Usually it has a clear external and internal contour. Purulent changes in fiber of retroperitoneal space are less likely to be ardent and more often resemble phlegmon. At the same time, ultrasound allows you to see the fuzzy contours of the muscles and the heterogeneous hypoechogenic contents between them and in the retroperitoneal space.

With an ultrasound, the visualization of the calculus in a kidney with a size of more than 0.5 cm does not represent significant difficulties. A single stone on echograms is defined as a clearly defined echopositive (hyperechogenic) formation with an acoustic path (shadow) more distal than the calculus. Its presence is associated with a complete reflection of ultrasound rays from the dense structures of the stone on the boundary of the section of the med. Certain difficulties arise when surrounded by small and flat stones. In the experiment, the minimum thickness of the stone located in the kidney and found during echography is about 1.5 mm. The most clearly calculi are visualized during dilatation of the cup-lobe system. Small hyperchogenic areas of a kidney sinus without an acoustic effect can be mistakenly interpreted as stones (cause of hyperdiagnosis).

With the help of ultrasound, any calculi can be detected, regardless of their chemical composition. That is why the metol is used for differential diagnosis of urate lithiasis and papillary neoplasms, when it is necessary to exclude the presence of x-ray in the kidney when detecting a filling defect in the cup-lobe system in urograms.

Non-invasive methods of echography allow you to determine the calculi in the cups. Lohanka, the upper third (with its dilatation) and the intramural section of the uretcher with a sufficiently filled with bladder. Stones in the middle and lower third of the ureter cannot be detected by the non-invasive method of echography. This is due to the presence of gas in the intestines, which prevents the passage of ultrasound waves. Only in rare observations in the absence of gas in the intestines and a significantly expanded ureter manage to visualize it fragmented in all departments. The detection of the calculus in any section of the urinary tract is possible using endoluminal echography, if there is a method of conducting an ultrasonic probe between the stone and the ureter wall.

Ultrasound signs of pathology of the kidneys and ureters

The use of ultrasound has greatly simplified the task of differential diagnosis of renal colic and acute processes in the abdominal cavity, as well as gynecological and neurological diseases. So, before the introduction of ultrasound methods for diagnostics in the receiving department of hospitals, the examination was carried out according to the following scheme: sightseeing radiography and excretory urography, chromocystoscopy, often blockade of the round ligament of the uterus or seed cord. Currently, an ultrasound is used to detect impaired renal outflow from the kidneys. If during the study of the kidneys of the dilatation of the cup-lobe system there was no, then the pain in the lumbar region in the patient is not associated with a violation of the outflow of urine from the Navy. However, we should not forget that in the absence of dilatation, the renal genes of pain and the presence of a urological disease cannot be completely excluded. The pain, similar to renal colic, is observed with kidney vessels, acute non-constructive inflammatory diseases of the kidneys and urinary tract, etc.

Modern ultrasound diagnostics has a functional orientation. The method to evaluate the functional state of the Navy is considered pharmacochography. For its implementation after the initial examination of the kidneys and determining the initial sizes of cups and pelvis, 10 mg of furosemide are intravenously administered. After that, every 5 minutes repeat the inspection and measurement of cups and pelvis. Polyuria can lead to dilatation of the cup-lobe system. The degree of which is evaluated by measurements. The study is repeated until its dimensions return to the original. Under normal conditions, dilatation is not expressed sharply and is present no more than 10 minutes. Its more long preservation (after the introduction of a saluretic during pharmacoichography) indicates the presence of an obstacle to the outflow of urine and/or the functional insolvency of the proximal urinary tract.

You can make an ultrasound of the kidneys in almost any medical institution having an apparatus of ultrasound diagnostics. Often the procedure is undergoing a doctor’s appointment for suspicions of pathology and impaired renal work.