Ultrasound diagnosis of kidney diseases. Kidney anatomy and

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The renal pyramids are the specific areas through which urine enters the collecting system after fluid is filtered from the bloodstream through tubular systems. Already from the PCA, urine moves through the ureter and enters the bladder. Violations of the pyramids can be observed both in one and both kidneys, which leads to dysfunction of the organ and requires mandatory treatment. Identification of pathological changes is carried out by means of ultrasound, and only after examination and diagnosis, the doctor prescribes the necessary therapy.

What does hyperechoic pyramids mean?

Pyramids of the kidneys are called certain zones through which urine enters the pelvicalyceal system after filtering fluid from the bloodstream.

The normal healthy state of the kidneys means the correct shape, uniformity of structure, symmetrical arrangement, and at the same time, ultrasound waves are not reflected on the echogram - a study performed with a suspected disease. Pathologies change the structure, appearance of the kidneys and have special characteristics that indicate the severity of the disease and the condition of the inclusions.

For example, organs can be asymmetrically enlarged/reduced, have internal degenerative changes in the parenchymal tissue - all leading to poor ultrasonic wave penetration. In addition, echogenicity is impaired due to the presence of stones and sand in the kidney.

Important! Echogenicity is the ability of wave reflection of sound from a solid or liquid substance. All organs are echogenic, which makes it possible to do ultrasound. Hyperechogenicity is a reflection of increased strength, revealing inclusions in organs. Based on the monitor readings, the specialist identifies the presence of an acoustic shadow, which is a determining factor in the inclusion density. Thus, if the kidneys and pyramids are healthy, the study will not show any wave abnormalities

Symptoms of hyperechogenicity

Syndrome of hyperechoic renal pyramids causes pain in the lower back of a cutting, stabbing nature

Hyperechoic renal pyramid syndrome has a number of symptoms:

Body temperature changes;
Pain in the lower back of a cutting, stabbing nature;
Changes in the color and smell of urine, sometimes blood droplets are observed;
Abnormal stool;
Nausea, vomiting.

The syndrome and symptoms indicate a clear kidney disease that needs to be treated. Isolation of pyramids can be caused various diseases organs: nephritis, nephrosis, neoplasms and tumors. Additional diagnostics, examination by a doctor and laboratory research to establish the underlying disease. After which the specialist prescribes therapeutic treatment measures.

Types of hyperechoic inclusions

All formations are divided into three types, based on what picture is visible on ultrasound

All formations are divided into three types, based on what picture is visible on ultrasound:

A large inclusion with an acoustic shadow most often indicates the presence of stones, focal inflammation, and disorders of the lymphatic system;

A large formation without a shadow can be caused by cysts, fatty layers in the sinuses of the kidneys, tumors of various types or small stones;

Small inclusions without a shadow are microcalcicates, psammoma bodies.

Possible diseases depending on the size of inclusions:

Urolithiasis or inflammation - manifests itself as large echogenic inclusions.

Single inclusions without a shadow indicate:

hematomas;
sclerotic changes in blood vessels;
sand and small stones;
scarring of organ tissue, for example, parenchymal tissue, where scarring occurred due to untreated diseases;
fatty seals in the sinuses of the kidneys;
cystosis, tumors, neoplasms.

Important! If the device monitor shows obvious sparkles without shadows, then in the kidneys there may be an accumulation of compounds (psammoma) of a protein-fatty nature, framed by calcium salts or calcifications. It is not recommended to ignore this symptom, as this may be the beginning of the development of malignant tumors. In particular, oncological formations include calcifications in 30% and psammonic bodies in 50%.

Inclusions of the echo complex of the kidneys on ultrasound are a study that allows us to identify abnormal developments of all parts of the organ, the dynamics of diseases and parenchymal changes. Depending on the echogenic indicators, the characteristics of the disease are determined, therapeutic and other treatment is selected.

As for the symptoms, even knowing about the pyramids in the kidneys, what they are, what pathologies are indicated by changes in structure and echogenicity, the invisibility of signs of the disease often does not cause concern. Patients come to terms with painful sensations and delay the visit to the doctor. It is categorically not recommended to do this: if the disease affects the pyramids, it means pathological changes have gone far enough and can result not only in purulent inflammatory processes, but also chronic diseases, the treatment of which will require a lot of time and money.

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03-med.info

Structure and purpose of parenchyma

Under the capsule lie several layers of dense parenchyma, differing both in color and consistency - in accordance with the presence of structures in them that allow the organ to perform the tasks facing the organ.

In addition to its most well-known purpose - to be part of the excretory (excretory) system, the kidney also performs the functions of an organ:

endocrine (intrasecretory);
osmo- and ion-regulating;
participating in the body both in general metabolism (metabolism) and in hematopoiesis - in particular.

This means that the kidney not only filters the blood, but also regulates its salt composition, maintains the optimal water content for the body’s needs, and influences the level of blood pressure, and in addition, it produces erythropoietin (a biologically active substance that regulates the rate of red blood cell formation).

Cortical and medulla layers

According to the generally accepted position, the two layers of the kidney are called:

cortical;
cerebral.

The layer lying directly under the dense elastic capsule, the outermost in relation to the center of the organ, the densest and most lightly colored, is called the cortical layer, while the layer located below it, darker and closer to the center, is the medulla layer.

A fresh longitudinal section reveals even to the naked eye the heterogeneity of the structure of the renal tissues: it shows radial striations - structures of the medulla, semicircular tongues pressing into the cortical substance, as well as red dots of the renal corpuscles-nephrons.

With purely external solidity, the kidney is characterized by lobulation, due to the existence of pyramids, delimited from each other by natural structures - renal columns formed by the cortex, dividing the medulla into lobes.

Glomeruli and urine formation

To make it possible to purify (filtrate) blood in the kidney, there are zones of direct natural contact of vascular formations with tubular (hollow) structures, the structure of which allows the use of the laws of osmosis and hydrodynamic (arising as a result of fluid flow) pressure. These are nephrons, the arterial system of which forms several capillary networks.

The first is a capillary glomerulus, completely immersed in a cup-shaped depression in the center of the flask-shaped expanded primary element of the nephron - the Shumlyansky-Bowman capsule.

The outer surface of the capillaries, consisting of a single layer of endothelial cells, is almost completely covered with intimately tightly adjacent cytopodia. These are numerous stalk-like processes that originate from the centrally passing cytotrabecula, which in turn is a process of the podocyte cell.

They arise as a result of the entry of the “legs” of some podocytes into the spaces between the same processes of other, neighboring cells, forming a structure reminiscent of a zipper lock.

The narrowness of the filtration slits (or slit diaphragms), determined by the degree of contraction of the “feet” of podocytes, serves as a purely mechanical obstacle for large molecules, preventing them from leaving the capillary bed.

The second wonderful mechanism that ensures the fineness of filtration is the presence on the surface of the slit diaphragms of proteins that have an electrical charge of the same name as the charge of the molecules approaching them in the composition of the filtered blood. This electrical “curtain” also prevents unwanted components from entering the primary urine.

The mechanism of formation of secondary urine in other parts renal tubule is caused by the presence of osmotic pressure directed from the capillaries into the lumen of the tubule, braided by these capillaries until their walls “stick” to each other.

Parenchyma thickness at different ages

Due to the onset of age-related changes, tissue atrophy occurs with thinning of both the cortical and medulla layers. If at a young age the thickness of the parenchyma is from 1.5 to 2.5 cm, then upon reaching 60 years or more it thins out to 1.1 cm, leading to a decrease in the size of the kidney (its wrinkling, usually on both sides).

Atrophic processes in the kidneys are associated both with maintaining a certain lifestyle and with the progression of diseases acquired during life.

Conditions that cause a decrease in the volume and mass of renal tissue are caused by both general vascular diseases of the sclerosing type and the loss of the ability of the renal structures to perform their functions due to:

voluntary chronic intoxication;
sedentary lifestyle;
the nature of the activity associated with stress and occupational hazards;
living in a particular climate.

Column Bertini

Also called Bertinian columns, or renal columns, or Bertin's columns, these beam-shaped strands of connective tissue, passing between the pyramids of the kidney from the cortex to the medulla, divide the organ into lobes in the most natural way.

Because inside each of them pass blood vessels, ensuring metabolism in the organ - the renal artery and vein, at this level of their branching they are called interlobar (and at the next - lobular).

Thus, the presence of Bertin's columns, which differ in a longitudinal section from the pyramids by a completely different structure (with the presence of sections of tubules passing in different directions), allows for communication between all zones and formations of the renal parenchyma.

Despite the possibility of the existence of a fully formed pyramid inside the particularly powerful column of Bertin, the same intensity of the vascular pattern in it and in the cortical layer of the parenchyma indicates their common origin and purpose.

Parenchymal bridge

A kidney is an organ that can take any shape: from the classic bean-shaped to a horseshoe-shaped or even more unusual.

Sometimes an ultrasound of an organ reveals the presence of a parenchymal bridge in it - a connective tissue retraction, which, starting on its dorsal (posterior) surface, reaches the level of the median renal complex, as if dividing the kidney crosswise into two more or less equal “half beans”. This phenomenon is explained by too strong wedging of Bertin's columns into the kidney cavity.

Despite all the seeming unnaturalness of this appearance of the organ and the absence of involvement of its vascular and filtering structures, this structure is considered a variant of the norm (pseudopathology) and an indication for surgical treatment is not, just like the presence of a parenchymal constriction dividing the renal sinus into two seemingly separate parts, but without complete doubling of the pelvis.

Regeneration ability

Regeneration of the kidney parenchyma is not only possible, but also safely carried out by the organ in the presence of certain conditions, which has been proven by many years of observation of patients who have suffered glomerulonephritis - an infectious-allergic-toxic kidney disease with massive damage to the renal corpuscles (nephrons).

Studies have shown that restoration of organ function occurs not through the creation of new ones, but through the mobilization of already existing nephrons, which were previously in a conserved state. Their blood supply remained sufficient solely to maintain minimal vital activity.

But activation of neurohumoral regulation after the subsidence of the acute inflammatory process led to the restoration of microcirculation in areas where the renal tissue was not subject to diffuse sclerosis.

These observations allow us to conclude that key point for the possibility of regeneration of the renal parenchyma is the possibility of restoring blood supply in areas where for some reason it has significantly decreased.

Diffuse changes and echogenicity

In addition to glomerulonephritis, there are other diseases that can lead to the appearance of focal atrophy of the renal tissue, which has varying degrees of extent, called by the medical term: diffuse changes in the structure of the kidneys.

These are all diseases and conditions that lead to vascular sclerosis.

The list can begin with infectious processes in the body (flu, streptococcal infection) and chronic (habitual household) intoxications: drinking alcohol, smoking.

It is completed by production and service-related hazards (in the form of work in an electrochemical, galvanic workshop, activities with regular contact with highly toxic compounds of lead, mercury, as well as those associated with exposure to high-frequency electromagnetic and ionizing radiation).

The concept of echogenicity implies the heterogeneity of the structure of an organ with varying degrees permeability of its individual zones for ultrasound examination(ultrasound).

Just as the density of different tissues is different for “translation” with X-rays, on the path of the ultrasound beam there are also both hollow formations and areas with high tissue density, depending on which the ultrasound picture will differ in great variety, giving an idea of internal structure organ.

As a result, the ultrasound method is truly unique and valuable. diagnostic study, not capable of being replaced by any other, allowing to give a complete picture of the structure and function of the kidneys, without resorting to an autopsy or other traumatic actions in relation to the patient.

Also, the outstanding ability to recover in case of damage can significantly regulate the lifespan of the organ (both by saving it by the owner of the kidneys and by providing medical care in cases requiring intervention).

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Syndrome of hyperechoic pyramids of the kidneys

If for a long time, then chronic renal failure, if acute, then acute renal failure. Poisoning can be the cause of both. The kidneys play an important role in the human body, and their normal functionality depends general state health. Therefore, when the first signs of malaise appear, it is recommended to immediately provide the necessary assistance to the kidneys.

Typical symptoms that cause kidney problems

When these symptoms appear, it is important to immediately contact your doctor, who will prescribe an immediate examination and delivery of the necessary tests. Also, these symptoms may indicate that the patient has one kidney larger than the other, so it is necessary to undergo an additional examination, including renal clearance. In the event that, after hypothermia, a person’s kidneys began to hurt, only one conclusion can be drawn - this means that the development of the inflammatory process began earlier.

Symptoms associated with kidney disease

A person can get closed injuries of the kidneys in car accidents, when falling from a height, and even while playing sports. Each of these types of diseases has its own dangers, so in no case should you experiment on yourself and self-medicate. Often, patients who actually have a carbuncle of the kidney end up in the hospital under completely different diagnoses.

Types of hyperechoic inclusions and diagnosis

With this disease, pus is also released, so it is very dangerous and requires immediate hospitalization of the patient in medical institution. It has been proven that dietary food has a very beneficial effect on many kidney diseases and allows them to work in a gentle mode.

The kidneys are a paired organ and perform several functions in the human body simultaneously. Therefore, during a diagnostic ultrasound examination, a mandatory examination of both kidneys is performed. Dysfunction may begin on one side and affect the other. Hyperechoic inclusions in the kidneys can be observed in either one or two. The location of the inclusions is the most diverse and depends on predisposing adverse factors.

Website about kidney diseases

Pathological processes of various etiologies change the structure and appearance of the kidneys depending on the severity of the disease and the condition of the inclusions. Hyperechogenicity means a super strong reflection, indicating the presence of any inclusions in the kidneys. There are several types of echogenic inclusions, which determine the pathological condition of the kidneys. Hyperechoic inclusions are divided into two large groups: stones (sand) and neoplasms.

Large inclusions in the kidneys. This can also be confirmed by the presence of calcifications and psammoma bodies in the tumor, as well as sclerotic areas. During the examination, several different types of echogenic inclusions may be detected. Renal dysfunction is always accompanied by weakness and fatigue. This condition is inherent in the acute development of diseases or the exacerbation phase of chronic pathological processes in the kidneys.

Therapeutic measures and prevention

It is necessary to evaluate the condition of the kidney parenchyma against the background of prominent pyramids. Depending on the severity of the condition and the type of pathological process, treatment can be therapeutic or surgical.

Pyelonephritis is an inflammatory process that occurs only in the pyelocaliceal system of the kidney, accompanied by pronounced laboratory changes. Rice. 1 Visualization of the right kidney. The sensor is located in the region of the posterior axillary line on the right.

Necessary treatment

As with a full examination of any other organs, it is necessary to examine the kidney in the second projection to study its cross section. The sensor can be installed directly under the costal arch or in the region of the last intercostal space.

Clinical manifestations

The left kidney is also located in a certain triangle, the sides of which are the spine, muscles and spleen. Sonographic characteristics of the renal capsule and parenchyma of the normal kidney are generally accepted.

A partial or complete rupture of the collecting system image at the same location indicates a doubling of the kidney with separate ureters and blood supply to each half.

Kidney dystopia is an anomaly of kidney development in which the kidney does not rise to its normal level during embryogenesis. In this case, variants of heterolateral dystopia with and without fusion of the kidneys are possible. When echographic detection of an abnormally located kidney, difficulties usually arise in the differential diagnosis of nephroptosis and dystopia. It must be remembered that a kidney with nephroptosis has a normal length ureter and a vascular pedicle located at the usual level (level L1-L2 of the lumbar vertebrae).

As for the increased echogenicity of the parenchyma and prominent pyramids, the reasons for this condition may be different. In newborns, the structure and condition of the pyramids themselves and the fluids released through them are assessed. The base of the triangle is the boundary between the cortex and the pyramid along the periphery of the cut of the pyramid. The syndrome itself is not life-threatening and is a symptom of a disease that is determined after a full comprehensive examination.

velnosty.ru

Concepts - hyperechogenicity and acoustic shadow?

Echogenicity is the ability of bodies of liquid and solid consistency to reflect ultrasonic waves. All organs located inside a person are echogenic, which is what allows ultrasound examination. Ultrasound helps to study the activity of the kidneys, determine their integrity and confirm or exclude the presence of neoplasms of a malignant or benign nature. U healthy person a rounded organ with a symmetrical location and the inability to reflect sound waves. In cases of pathologies, the size of the kidneys changes, the location becomes asymmetrical and inclusions appear that can deflect sound waves.

On ultrasound, hyperechoic inclusions appear as white spots.

The word “hyper” refers to the increased ability of echogenic tissues to reflect ultrasound waves. During an ultrasound, the specialist sees white spots on the screen and determines whether they have an acoustic shadow, or more precisely, an accumulation of ultrasonic waves that did not pass through it. Waves have a much higher density than air, so they cannot travel exclusively through a dense object. Hyperechogenicity is not a separate disease, but a symptom that indicates the appearance of various types of pathologies inside the kidneys.

When assessing anechoic focal formation kidneys, the sonographer must ensure the presence diagnostic criteria, corresponding to a simple cyst. If the mass does not meet these criteria, it is not a simple cyst. A cyst is diagnosed as complex if it has features indicating the presence of septations, suspension, or wall thickening. A complex cyst may have signs of infection, hemorrhage, tumor growth, which in turn will require additional research. When examining a complex cyst, the doctor must conduct several sequential ultrasound scans, and also correlate the ultrasound data with computed tomography or aspiration biopsy.

Polycystic kidney disease. Polycystic kidney disease in adults is often accompanied by bilateral enlargement. At the same time, multiple cysts are determined in the kidneys. Cysts are also detected in the liver (in 33% of cases), less often - in the pancreas and spleen. Some cysts are complex and contain echogenic complexes due to infection or hemorrhage.

Bertin columns. Bertin's columns are one of the variants of the normal anatomy of the kidneys. They look like a continuation of the cortical layer of the kidney into the renal sinus. These structures should not be mistaken for kidney tumors. The columns are extensions of the renal cortex and their echostructure is the same as that of the cortex. In these columns one can often see pyramids of the medullary layer.

Hydronephrosis. Moderate expansion of the renal collecting system with expansion of the large and small calyces is expressed in the appearance of anechoic finger-like structures throughout the renal sinus. Hydronephrosis can be caused by ureteral stones, swelling of its walls, or neoplasms. The ureter is usually not visualized even with significant hydronephrosis.

Kidney carcinoma. Most renal carcinomas appear as solid lesions. These tumors may be isoechoic or hypoechoic; small renal carcinomas are often hyperechoic. Less often, such formations are defined as complex cysts. When performing an ultrasound scan of a kidney containing a mass, it is necessary to visualize the renal veins and the inferior vena cava to exclude the presence of a tumor thrombus in their lumen. The combination of ultrasound and CT data improves the accuracy of tumor description.

During the ultrasound A thorough and systematic scan is carried out. When scanning in the longitudinal plane, always move the probe from one edge of the kidney to the other (from medial to lateral, from lateral to medial); In addition, visualize and evaluate all structures on a transverse plane scan. This research technique reduces the likelihood that a focal kidney formation will be missed.

Lower pole of the kidney not fully rendered due to the shadow cast by the edge. If visualization is poor, move the transducer (and/or patient) to obtain a full view of the lower pole. After this, a large solid formation is visualized in the lower pole of the kidney.

Educational video of normal kidney ultrasound

Table of contents of the topic “Ultrasound of the pancreas and genitourinary system”:

In our observations, it was detected in 0.2% of patients, and in most cases in boys. Echodiagnosis presents certain difficulties, which increase when this anomaly is combined with various diseases (hydronephrosis, cysts, polycystic disease, hematomas, paranephritis, tumors, injuries).

An unaffected horseshoe kidney is always located lower than a normal kidney, has a large size, but never gains the sum of two normal renal sizes, the zone of parenchyma and the collecting system is well demarcated. Visualization and differentiation are improved by applying aqueous pressure, which allows for good differentiation of dilated pelvises. It should be noted that echographically it is very difficult to determine which poles the kidneys are fused with, except in cases where, when viewed through the anterior abdominal wall, it is possible to locate the adrenal glands at the opposite poles, and then this is only possible with an anomaly of the left kidney.

Biscuit bud

This anomaly is very rare and is formed as a result of the uniform action of forces small intestine during the period of kidney advancement from the pelvis to the lumbar region. When they are retained in the pelvis, fusion occurs along the entire length. The kidney is located low in the pelvis as a flat-oval-elongated formation with clear contours, delimiting the zone of parenchyma and the collecting-pelvic system without differentiating the site of fusion. May be mistaken for a tumor. Echodiagnosis of a biscuit-shaped kidney is difficult when combined with various diseases. Priority goes to excretory urography.

Asymmetric forms of fusion include kidneys fused in the form of the Latin letters S, I and L. With this anomaly, the kidneys are fused with opposite poles due to the uneven impact of the forces of the small intestine during their movement from the pelvis to the lumbar region. The longitudinal axes of S and 1-shaped fused buds are parallel. The S-shaped kidney is located in the pelvis in a horizontal or oblique position, and the I-shaped kidney is located vertically and parallel to the inferior vena cava and the abdominal aorta.

With an L-shaped kidney, the longitudinal axes are perpendicular and located in the pelvis in horizontal position. It should be noted that this anomaly is easily confused with a horseshoe kidney. Typically, abnormal kidneys have clear contours with a well-differentiated zone of parenchyma and often zones of two pyelocaliceal systems. Sometimes with an S-shaped kidney, it is possible to isolate the isthmus (site of fusion). Despite the fact that echography reveals the presence of abnormal kidneys, excretory urography takes priority in their differential diagnosis.

Quantity anomalies

Double kidney

The most common abnormality in the number of kidneys (approximately 4%) is kidney duplication, which can be unilateral or bilateral, complete or incomplete.

Paired kidney

With complete duplication, there are two collecting systems - two pelvis, two ureters and two vascular bundles. The echogram clearly shows the pelvis, the beginning of the ureters, and sometimes it is possible to identify vascular bundles.

An incompletely duplicated kidney differs from a complete one in that it is fed by one vascular bundle. The ureter can be doubled at the top and enter the bladder with one or two orifices. On the echogram, the double kidney looks elongated and is present characteristic feature separation of zones of the parenchyma and the pyelocaliceal system.

Difficulties in echographic differentiation arise with pyelonephritis, hydronephrosis, urolithiasis and tumors of one of the halves of a double kidney. The full anatomical picture of a double kidney can only be seen radiographically.

This pathology is extremely rare. Paired buds can be one- or two-sided, identical or different in size. According to our data (there is no description of this pathology in the available literature), a unilateral paired kidney was identified in 5 older women and a bilateral one in 2 pregnant women aged 21 and 28 years. In 6 out of 7 cases that we identified, the paired kidneys were of the same size, on average 8.2-3.6 cm. The width of the kidney was taken as only 1/2 the width of the parenchyma zone in the fused part of the kidneys.

A characteristic feature is their longitudinal fusion with lateral surfaces. The echostructure of paired kidneys does not differ from that of a normal kidney, that is, the zones of the parenchyma and the pyelocaliceal system are very clearly distinguished. A special feature is that the width of the parenchyma zone at the site of fusion does not exceed the value in the non-fused part of the kidneys. Based on the echo picture, it can be assumed that fusion occurs at the level of the entire thickness of the parenchyma of both kidneys. The option of complete longitudinal doubling of the kidney is not excluded. The ureters behave in the same way as with a complete double kidney.

Abnormality of the renal parenchyma

Abnormalities of the renal parenchyma include agenesis, aplasia, hypoplastic kidney, accessory (third) kidney, additional lobule and cystic anomalies of the parenchyma - polycystic, multicystic, solitary cyst, multilocular cyst, spongy kidney, megacalycosis and calyx diverticulum.

Agenesis

Congenital absence of one or both kidneys. With unilateral agenesis, the specific structure of the kidney is not located on this side, but sometimes it is possible to locate an enlarged adrenal gland. On the opposite side, a hypertrophied kidney, defective in echo structure, is located.

However, it should be remembered that the absence of a kidney in an anatomical location does not indicate the presence of agenesis. The final diagnosis can be made only after detailed echographic and radiological studies. Bilateral agenesis is very rare and is diagnosed in the fetus in the second and third periods of pregnancy, when all organs are developed. However, a thorough echographic examination does not reveal the echostructure of the kidneys and bladder. The study is difficult to carry out, since with this anomaly there is always oligohydramnios. Fetuses with this anomaly are born dead.

Aplasia

Profound underdevelopment of the renal parenchyma with frequent cases of absence of the ureter. It can be one-sided or two-sided.

With unilateral aplasia, there is no specificity of the kidney structure and an oval-elongated formation with unclear erased contours, heterochoic (of different acoustic densities) is located, although small cysts and calcifications can be located. It is not clinically manifested and is an echographic finding when examining the kidneys.

Bilateral aplasia is extremely rare. In this case, the fetus cannot be imaged of the kidneys and bladder.

Hypoplastic kidney

Congenital reduction in kidney size. On the echogram, the kidney is reduced in size (on average 5.2 cm long, 2.4 cm wide), the zones of the parenchyma and the collecting system are narrowed, but the specificity of the structure of these zones is preserved.

In 3 patients, we observed a dwarf kidney measuring 3-2 cm. The contours of the kidney were blurred, the parenchyma was heterogeneous in echogenicity; There is no division into zones.

It should be remembered that it can be very difficult to distinguish a hypoplastic kidney from a wrinkled kidney, in which the size is also reduced, but the latter has blurred contours and division into zones; such a kidney is poorly demarcated from the tissues surrounding it.

Accessory (third) kidney

It is extremely rare. We identified 2 cases. The accessory kidney is usually located below the main one and may be slightly smaller than it. In our cases, the main and accessory kidneys were located in a horizontal plane and had the same dimensions, but slightly smaller than the generally accepted average values for this age (7.1-2.8 cm). The parenchyma and pyelocaliceal system in both kidneys are clearly visible. The ureter of the accessory kidney can empty into the main ureter or independently into the bladder.

There can be one (or several) additional lobule of one of the kidneys and is most often located at the poles, located as a small oval formation with clear contours; the echostructure of the lobules is similar to that of the tissue of the main kidney. Sometimes additional lobules can be easily mistaken for the adrenal gland, although their echo structure is somewhat different, sometimes they can be confused with a space-occupying formation growing exophytically.

Anatomical variations of the normally functioning kidney

There are anatomical variations in the structure of the parenchyma and pyelocaliceal system of the kidney. It should be noted right away that they have no clinical significance, however, some of them may pose diagnostic problems for the researcher.

A parenchymal defect is rare and is located in the form of an echogenic zone of a triangular shape, the base of which is connected with the fibrous capsule, and the apex with the wall of the renal sinus.

Kidney with oval-convex uneven outer contour

Occurs quite often. It is characterized by isolated hypertrophy (bulging in the form of a hump) of the parenchyma towards the outer edge of the middle third of the kidney. An inexperienced specialist may mistake it for a tumor with exophytic growth or a carbuncle (with the latter there is an acute clinical picture).

Uneven lobulated kidney

It usually occurs in children under 2-3 years of age. Rarely does this phase of embryonic structure persist in adults. It is characterized by a uniform division into 3-4 bulging outer surface zones of low echogenicity (parenchyma of the lobules).

Kidney with an isolated area of hypertrophy of the parenchyma inside

This anomaly of the parenchyma is quite common; it is characterized by isolated hypertrophy and protrusions in the form of a pseudopodium between two pyramids up to the pyelocaliceal system, which, in the absence of a clinic, we tend to consider a variant of the individual norm. It can be mistaken for a tumor, and therefore patients with exophytic and endophytic additional growth of parenchyma should be subjected to invasive research methods.

Polycystic kidney disease

Congenital, always bilateral cystic anomaly of the kidney parenchyma.

Before the introduction of echography, especially in real time, the diagnosis of polycystic disease presented great difficulties, since the percentage of correct diagnosis by X-ray methods did not exceed 80. In our observations of more than 600 patients, echographic diagnosis turned out to be correct in 100% of cases. The polycystic kidney is always enlarged in size, the contours are uneven, oval-convex, the echostructure is not differentiated, only strips of parenchyma and many rounded different sizes anechoic formations (cysts), separated by thin echogenic strips-septa. Sometimes polycystic kidney takes on the appearance of a bunch of grapes. But in most cases, several large cysts, up to 5-6 cm in diameter, are located, surrounded by many small ones. Sometimes, during dynamic observation of the patient, one can observe the disappearance of large cysts and their ruptures.

The study is performed from the back, but visualization of the right kidney is better through the liver. It should be noted that with a significant size of the kidney and the presence of many cysts, sometimes the liver is only partially visible or not visible at all, and it is possible to mistakenly diagnose polycystic liver disease, which is extremely rare.

Multicystic dysplasia

A congenital anomaly, which is often unilateral, since bilateral is incompatible with life. The multicystic kidney is usually large in size, characterized by uneven contours, the parenchyma is not differentiated and is completely replaced by cysts of various sizes, usually 2-3 large ones. For the purpose of differential diagnosis of polycystic and multicystic diseases, X-ray examination methods are used. Multicystic kidney disease is characterized by high obliteration of the ureter.

Solitary cyst

There are congenital and acquired kidney cysts. Congenital cysts are detected in the fetus in the second and third trimesters of pregnancy or more often in childhood. Acquired cysts are detected more often after 40 years. There are single and multiple, but no more than 2-3 in one kidney. They are located as round formations of different sizes: minimum - 0.5 cm, maximum - over 10 cm in diameter. They originate from the kidney parenchyma and have clear contours, are devoid of echo signals, and are located both on the surface and in different parts of the kidney.

It is difficult to clarify the location of the cyst; First of all, this applies to parapelvic cysts located in the area of the renal hilum. In some cases, they are difficult to differentiate from an enlarged pelvis, hydronephrosis, which may have a similar oval shape. In this regard, it should be remembered that in the case of hydronephrosis, echolocation of the kidney in different scans almost always reveals an interruption of the contours of the fluid formation, that is, a connection with the pelvis and the ureteropelvic segment and calyces, whereas with parapelvic cysts, no interruption of the contours of the located fluid formation is observed.

It should be remembered that the image of cysts may be overlaid on the right kidney right lobe liver or right half abdominal cavity, in particular the intestinal mesentery in Crohn's or ovarian disease. A cyst of the lower pole of the spleen, the tail of the pancreas, the left half of the abdominal cavity, the left ovary, or fluid in the stomach with poor evacuation can be mistakenly mistaken for a cyst of the left kidney. Such diagnostic errors are unacceptable, because they lead to serious complications, since access for surgical intervention for these pathologies are different. To avoid mistakes, it is necessary to carefully differentiate the contours of the kidney in different echographic scans by changing the position of the body. In doubtful cases, repeated ultrasound examinations and laparoscopy are indicated.

Echography allows for dynamic monitoring of the growth and condition of cysts (suppuration, rupture, resorption). The dynamics of the development of cysts is of great clinical importance, since their growth is associated with atrophy of the kidney parenchyma, leading to hemodynamic disturbances and arterial hypertension. Echography helps clarify the moment of possible surgical intervention or conservative treatment, and provides conditions for conducting a targeted diagnostic or therapeutic biopsy.

Dermoid cysts

These are congenital single-chamber, rarely multi-chamber, round formations outlined by an echogenic capsule. Can be located in various parts of the body, rarely in internal organs and very rarely in the kidneys. They are more common in girls in early childhood, although they can also occur in adults, and be an accidental finding. Depending on their content (hair, fat, bone tissue, etc.), the contents of the formation have different echogenicity - part of the cyst can be high, and part - low (fluid). The wall of the dermoid cyst is thickened, has high echogenicity, and sometimes undergoes calcification and is located as a round, highly echogenic ring, clearly visible on x-ray. It should be noted that sometimes a dermond cyst is echographically difficult to distinguish from a chronic abscess, decay of a cavity and tumor, hypernephroma and Wilms tumor. The diagnosis in such cases can be confirmed by core aspiration biopsy or surgery.

Multilocular cyst

A very rare anomaly (2 cases identified), characterized by the replacement of a section of the renal parenchyma with a multilocular cyst, which is located as a multilocular anechoic formation, separated by narrow echogenic septa. When large sizes are reached, the echo picture is the same as with a multi-chamber hydatid cyst. Differentiation is very difficult. The only distinguishing feature is that an active hydatid cyst gives fast growth compared to multilocular cyst (in household the patient usually has animals that are carriers of echinococcosis).

Sponge bud

A rare anomaly in which the renal collecting ducts are dilated.

Males are more often affected. In this case, the kidney can be increased in size, characterized by a uniform cystic lesion of the pyramids, usually bilateral, without involving the cortex in the pathological process. Cysts are usually small in size, with a diameter of 3 to 5 mm, directed towards the center of the kidney. Although many small cysts can also occur on the surface of the kidney, making it uneven. Many small stones are located in the area of the pyramids. When pyelonephritis is associated, echodiagnosis is difficult.

Megacalycosis (renal calyx dysplasia)

Congenital enlargement of the renal calyces associated with underdevelopment of the renal pyramids. Usually this anomaly is unilateral, although cases of bilateral lesions have been described. In this case, all calyces are affected.

On the echogram, all the calyces are significantly dilated, have a rounded shape, the pelvis, as a rule, unless pyelonephritis is associated, is not dilated, the ureter is freely passable for contrast agent during x-ray examination.

Accumulation of uric acid salts and small stones can be detected. Echography of this pathology can only suggest that the final diagnosis is based on excretory urography and retrograde pyelography, where the cyst cavity, a narrow passage communicating with the renal calyx, is clearly visible.

Calyceal diverticulum

Congenital cystic formation, connected to the minor renal calyx by a narrow canal.

Megaureter

Congenital unilateral, less often bilateral segmental expansion along the entire length of the ureter, from 3 mm to 2-3 cm or more, the ureter is located as an anechoic tube of uneven width over a narrowed distal segment.

The length of the ureter can vary from 0.5 to 4-5 cm; the left ureter is most often affected. Megaureter can be primarily obstructive (congenital), secondary obstructive (acquired) due to inflammatory processes, postoperative scars and other reasons, and primarily non-obstructive (idiopathic). Megaureter, especially primarily obstructive, always leads to hydronephrosis and hydrocalycosis.

Ureterocele

One of the rare anomalies of the ureter, arising due to the narrowness of its mouth, in which there is an expansion of all layers of the intramural part of the ureter, protruding in the form of an oval echo-negative formation into the bladder cavity on one or both sides. The cavity of the ureterocele may contain urine - from a few milliliters to the volume of the bladder.

A ureterocele is difficult to differentiate from a diverticulum or hydatid cyst located at the orifice of the ureter.

Early diagnosis of ureterocele is of great importance, as it allows timely relief of the patient from possible dilatation of the upper urinary tract and the development of pyelonephritis and secondary cystitis.

Renal vascular abnormality

This area of pathology for modern echography, even with the use of Doppler, is little or, more precisely, only partially accessible. It allows only to assume the presence of some vascular pathology when comparing structural changes in the renal parenchyma.

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Difficulties and errors in ultrasound and x-ray diagnostics of renal pseudotumors

State Medical Academy,

MySono-U6

Introduction

Kidney tumors account for 2-3% of all malignant neoplasms. Most often they occur in adulthood. Among all kidney tumors, 80-90% are renal cell carcinoma. IN last years the likelihood of its detection increases, which is associated both with the increase in the number of all malignant tumors and with early preclinical diagnosis. Recognizing malignant formations, first of all, is made possible by constantly improving and widely used ultrasound examinations of the kidneys.

The first report on the use of ultrasound in the diagnosis of kidney tumors was published in 1963 by J. Donald. Since then the accuracy ultrasound diagnostics kidney tumors increased from 85-90% to 96-97.3%. When using modern ultrasound scanners operating in tissue and second harmonic modes, as well as color Doppler and energy mapping and dynamic echo-contrast angiography, the sensitivity of ultrasound (ultrasound) is 100% with a specificity of 92 and predictability of a positive test of 98%, and a negative test of 100%. .

In the literature, there are often publications devoted to errors not only in ultrasound, but also in other methods of radiation diagnostics. There is a point of view that up to 7-9% of all volumetric processes in the kidneys cannot be differentiated from operations for cysts, tumors, abscesses, etc. . The picture of a kidney tumor with ultrasound and other radiation diagnostic methods can be simulated by many processes. Among them: various kidney anomalies; “complex” or mixed cysts; acute and chronic nonspecific inflammatory processes(carbuncle, abscess, chronic, including xanthogranulomatous pyelonephritis); specific inflammatory processes (tuberculosis, syphilis, fungal infections of the kidneys); changes in the kidneys with leukemia and lymphoma, including HIV infection; kidney infarctions; organized hematomas and other reasons.

In this message we will only talk about kidney anomalies, which in the literature are defined by the term pseudotumors. With them clinical manifestations almost always absent or determined by concomitant diseases, and establishing the correct diagnosis is possible only by radiological diagnostic methods (Fig. 1).

Rice. 1. Variants of pseudotumors that mimic a tumor.

Materials and methods

Over the years 177 patients with different structures of the renal parenchyma according to the type of renal pseudotumors were observed. All of them underwent repeated ultrasound scans of the kidneys, Doppler ultrasound (USDG) of renal vessels - 78, including using the second and tissue harmonics and power Doppler modes - 15, excretory urography (EU) - 54, X-ray computed tomography (X-ray computed tomography) - 36, renal scintigraphy or emission computed tomography (ECT) with 99 m Tc - 21.

Research results

Fetal lobulation of the kidney (see Fig. 1) with multiple protrusions along the lateral contour of the kidney was not considered in this report, since it did not require differential diagnosis with a kidney tumor. Among 177 patients with renal pseudotumors, 22 (12.4%) had a variant of the lobulated kidney - “humpbacked” kidney” (Fig. 2). In 2 (1.2%) patients, an enlarged “lip” above the renal hilum was noted (Fig. 3a-c). The most common cause of pseudotumor was “hypertrophy” of Bertin’s columns or “bridges” of the renal parenchyma - in 153 (86.4%) patients (Fig. 3 d-f). “Bridges” of the parenchyma were noted not only with various duplications of the renal pyelocaliceal systems, but also with their various fusions and incomplete rotations of the kidneys.

37 (21%) patients required differential diagnosis of pseudotumors and renal tumors. For this purpose, first of all, repeated “targeted” ultrasound scans were carried out using various additional ultrasound techniques in a urological clinic, as well as other methods of radiation diagnostics mentioned above. In only one patient with a pseudotumor of the kidney, an exploratory lumbotomy with intraoperative ultrasound-guided biopsy was performed to exclude the diagnosis of a tumor. In the remaining 36 patients, the diagnosis of renal pseudotumors was confirmed using radiation studies and ultrasound monitoring.

Rice. 2. Echogram (a) and a series of computed tomograms (b) with a “humpbacked” left kidney.

Rice. 3. Echogram, excretory urogram, computed tomogram with contrast enhancement with an enlarged “lip” of the kidneys on both sides (a-c) and hypertrophy of Bertin’s column (incomplete “bridge” of the parenchyma) in the middle section of the right kidney (d-f), respectively.

Difficulties and errors in radiological diagnostics for renal pseudotumors usually arose at the first prehospital stages diagnostics In 34 (92%) patients, they were associated both with objective difficulties in interpreting unusual echographic data, and with their incorrect interpretation due to insufficient qualifications of specialists and the relatively low level of diagnostic equipment. In 3 (8%) patients, there was an erroneous interpretation of X-ray computed tomography data, when there was a discrepancy between them and the data of repeated ultrasound scans and X-ray computed tomography in the urology clinic.

Kidney tumors that were combined with a pseudotumor in one kidney were verified in 2 patients after nephrectomy, and pseudotumors were verified in one patient during ultrasound-guided biopsy during exploratory lumbotomy; for the rest - with ultrasound monitoring for periods from 1 to 10 years.

Discussion

One of the most common reasons simulating a kidney tumor during ultrasound examination, the so-called pseudotumor, is most often defined in the literature by the term hypertrophy of Bertin's column.

As is known, along the periphery of an ultrasound section of the kidney, the cortex forms invaginations in the form of columns (columnae Bertin) between the pyramids. Often Bertin's column extends quite deeply beyond the internal contour of the parenchyma into the central part of the kidney - into the renal sinus, dividing the kidney more or less completely into two parts. The resulting peculiar parenchymal “bridge” is the unresolved parenchyma of the pole of one of the kidney lobules, which merge into the kidney of an adult during the process of ontogenesis. The anatomical substrate of the “bridges” is the so-called connective tissue defects of the parenchyma or prolapse of the latter into the renal sinus. It consists of the cortex, Bertin's columns, and renal pyramids.

All elements of the “bridge” are normal parenchymal tissue without signs of hypertrophy or dysplasia. They represent a duplication of the normal renal cortex or an additional layer of it located lateral to the calyces. The latter is an option anatomical structure parenchyma, in particular, the corticomedullary relationship between the parenchyma and the renal sinus. They can be most clearly seen on ultrasound and computed tomographic sections of the kidney.

The absence of hypertrophy or dysplasia of the parenchyma with the so-called hypertrophy of Bertin’s columns or “bridges” of the parenchyma was confirmed by histological studies biopsy material in one patient with “bridges” of parenchyma, which were taken for a kidney tumor before explorative lumbotomy, and also in two patients during a morphological study of kidneys removed due to a combination of a tumor and a pseudotumor in one kidney (“bridges” of parenchyma).

In this regard, in our opinion, the term hypertrophy of Bertin's columns, which is most often found in the literature, does not reflect the morphological essence of the substrate. Therefore, we, like a number of authors, believe that the term “bridge” of parenchyma is more correct. We used it for the first time in the domestic literature on ultrasound diagnostics in 1991. It should be noted that the term “bridge” of parenchyma had other names in the literature (table).

Table Terms used to describe the “bridges” of the renal parenchyma (according to Yeh HC, Halton KP, Shapiro RS et al., 1992)

Wolfman NT et al., 1991

Leekman RN et al., 1983

Many years of experience in excretory urography have shown that the collecting system has an extremely large number of structural options. They are practically individual not only for each person, but also for the left and right kidneys in the same subject. With the development and increasingly widespread use of ultrasound and X-ray CT, which makes it possible to trace both the internal and external contours of the renal parenchyma, in our opinion, a similar situation is emerging with regard to the variants of the anatomical structure of the renal parenchyma. A comparison of echo and computed tomographic data with urographic data for various types of renal pseudotumors showed that there is a relationship between the anatomical structure of the parenchyma and the renal collecting systems. It is expressed in the congruence of the medial contour of the parenchyma in an echo or computed tomographic image with the lateral contour of the pyelocaliceal systems, conventionally drawn on excretory urograms or on contrast-enhanced computed tomograms. This symptom can be traced with the usual structure of the parenchyma and pyelocaliceal systems, as well as with the “bridge” of the kidney parenchyma, which is a variant of the anatomical structure. With a kidney tumor, which is an acquired pathological process, the congruence of the contours of the parenchyma and the renal pyelocaliceal systems is disrupted (Fig. 4).

Rice. 4. Symptom of congruence of the contours of the parenchyma and the pyelocaliceal system of the kidney with an incomplete “bridge” of the parenchyma (explanation in the text).

conclusions

Thus, the typical echographic images of a “bridge” of the renal parenchyma, a “humpbacked” kidney and an enlarged “lip” above the renal hilum without signs of dilation of the pyelocaliceal systems, first identified by ultrasound, do not require further examination.

If differential diagnosis of pseudotumors and renal tumors is necessary, which was required in 37 (21%) patients, we propose the following algorithm for their diagnosis (Fig. 5).

Rice. 5. Algorithm for radiation diagnostics for pseudotumor of the kidney.

Repeated ultrasound by qualified specialists on higher-class ultrasound scanners using ultrasound, mapping techniques, tissue and second harmonics.
X-ray computed tomography with contrast enhancement or excretory urography with comparison of uro- and echographic data and data from repeated “targeted” ultrasound.
The methods of choice are renal scintigraphy or emission computed tomography with 99 m Tc (false-negative results are possible for small tumors).
If there is still suspicion of a malignant tumor, a biopsy under ultrasound guidance (only a positive result has diagnostic value).
At negative result biopsy or the patient refuses a biopsy and surgical revision of the kidney, ultrasound monitoring is performed at least once every 3 months in the first year of observation, and then 1-2 times a year.

Literature

Demidov V.N., Pytel Yu.A., Amosov A.V. // Ultrasound diagnostics in urology. M.: Medicine, 1989. P.38.
Hutschenreiter G., Weitzel D. Sonographic: einewertwolle erganzung der urologichen Diagnostic // Aktuel. Urol. 1979. Vol. Bd 10 N 2. P. 45-49.
Nadareishvili A.K. Diagnostic capabilities of ultrasound in patients with kidney tumors // 1st Congress of the Association of Ultrasound Diagnostics in Medicine: Abstracts of reports. Moscow. October 1991. P.121.
Buylov V.M. Complex application and algorithms of ultrasound scanning and x-ray diagnostics for diseases of the kidneys and ureters: Dis. . doc. honey. Sci. M., 1995. P. 55.
Modern ultrasound diagnostics of volumetric formations of the kidneys / A.V. Zubarev, I.Yu. Nasnikova, V.P. Kozlov et al. // 3rd Congress of the Association of Ultrasound Diagnostics in Medicine: Abstracts of reports. Moscow. October 1999. P. 117.
US, CT, X-ray diagnosis of Renal Masses / R.K. Zeman, J.J. Croman, A.T. Rosenfield et al. // Radiographics. 1986. Vol.6. P..
Thomsen H.S., Pollack H.M. The Genitourinary System // Global TextBook of Radiology. (Ed.) Petterson H. 1995. P..
Lopatkin N.A., Lyulko A.V. Anomalies of the genitourinary system. Kyiv: Health, 1987. pp. 41-45.
Mindel H.J. Pitfalls in Sonography of Renal Masses // Urol. Radiol. 1989. 11. 87. N 4. R..
Burykh M.P., Akimov A.B., Stepanov E.P. Echography of the kidney and its pyelocaliceal complex in comparison with data from anatomical and x-ray studies // Arch. Anat. Gistol. Embryol. 1989. T.97. N9. P.82-87.
Junctional Parenchyma: Revised Definition of Hypertrophic Column of Bertin / H-Ch. Yeh, P.H. Kathleen, R.S. Shapiro et al. // Radiology. 1992. N 185. R..
Bobrik I.I., Dugan I.N. Anatomy of human kidneys during ultrasound examination // Vrach. case. 1991. N 5. P. 73-76.
Khitrova A.N., Mitkov V.V. Renal ultrasound: Clinical guide to ultrasound diagnostics. M.: Vidar, 1996. T. 1. S., 209, 212.
Builov V. Junctional parenchyma or hypertrophic column of Bertini: the congruence of their contours and calyceal-pelvic system // Abstracts of ECR’99, March 7-12. 1999. Vienna Austria.-Europ. Radiol. Supp.1. Vol.9. 1999. S.447.
Builov V.M., Turzin V.V. Echotomography and excretory urography in the diagnosis of “bridges” of the renal parenchyma // Vestn. radiol.radiol. 1992. N 5-6. pp. 44-51.
Builov V.M., Turzin V.V. Diagnostic value of atypical “bridges” of parenchyma during sonography of the kidneys // 1st Congress of the Association of Ultrasound Diagnostics in Medicine: Abstracts of reports. Moscow. October 1991. P. 121.
Buylov V.M. Questions of terminology and a symptom of congruence of the contours of “hypertrophied” columns of Bertini or “bridges” of the parenchyma and pyelocaliceal systems of the kidneys // Vestn. rentgenol. and radiol. 2000. N 2. P. 32-35.
Buylov V.M. Algorithm for radiodiagnosis of kidney pseudotumors // Abstracts of reports. 8th All-Russian Congress of Radiologists and Radiologists. Chelyabinsk-Moscow. 2001. S..

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Publications on the topic

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Ultrasound and X-ray diagnostics of renal pseudotumors.
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Multiplane sonography of the prostate.

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3.1. Kidneys

Modern ultrasound diagnosis of kidney diseases is impossible without a clear understanding of the normal echoanatomy of the kidney, based on a comparison of the echographic picture and the histomorphological substrate.

The kidneys are located retroperitoneally. The right kidney is at the level of Th-12-L-4, the left kidney is located higher – at the level of Th-11-L3 vertebra. However, determining the position of the kidney relative to the vertebrae is quite inconvenient, therefore, in echographic practice, the hypoechoic acoustic “shadow” from the twelfth rib, the dome of the diaphragm (or the diaphragmatic contour of the liver), the hilum of the spleen, and the contralateral kidney are used as a guide to determine the position of the kidney. Normally, the acoustic “shadow” from the twelfth rib crosses (during longitudinal scanning from the back parallel to the long axis of the kidney) the right kidney at the level of the boundaries of the upper and middle third, the left kidney at the level of the renal hilum. The upper pole of the right kidney is located at the level or slightly below the upper phrenic contour of the right lobe of the liver. The upper pole of the left kidney is located at the level of the hilum of the spleen. The distances from the upper pole of the right kidney to the contour of the diaphragm and from the upper pole of the left kidney to the hilum of the spleen depend on the degree of development of the perinephric tissue of the subject.

Kidney sizes, according to N.S. Ignashin, are 3.5 - 4.5 cm on a longitudinal section, 5-6 cm and 3.5 - 4.5 cm on a transverse section. The total thickness of the parenchyma is 1.2 - 2.0 cm in the middle segment, 2.0 – 2.5 cm in the region of the poles of the kidney. The normal kidney volume is 300 cm3. According to V.N. Demidov, kidney length 7.5 – 12 cm, width 4.5 – 6.5 cm, thickness 3.5 – 5 cm. According to M.P. Burykh and the specialists who carried out anatomical-echographic correlations, the length of the kidney is 10.41 + 1.3 cm, the width of the kidney is 5.45 ± 1.3 cm, and the thickness is 3.63 ± 0.5 cm.

The cut shape of a normal kidney in all projections is bean-shaped or oval. The contour of the kidney is usually smooth, and if there is preserved fetal lobulation of the kidney, it is wavy (this is a variant of the normal structure of the kidney). Quite often, a local bulging of the contour is normally detected in the area of the lateral edge of the kidney (in this case, the so-called “humpbacked” kidney is defined) or in the area of the edge of the renal sinus, which simulates a kidney tumor. These conditions are described as pseudotumors and are also variants of the normal kidney structure. One of distinctive features pseudotumor "bulges" of the parenchyma with preserved fetal lobulation of the kidney, in contrast to the tumor, is the preservation of parallelism of the outer and internal contours of the parenchyma, the preservation of the normal echostructure of the parenchyma.

In Fig. Figure 18 shows an echogram of a normal adult kidney.

Sonographic characteristics of the renal capsule and parenchyma of the normal kidney are generally accepted. Along the periphery of the ultrasound section of the kidney, a fibrous capsule is visible in the form of a hyperechoic, smooth, continuous structure 2–3 mm thick, then the parenchyma layer is determined. The renal hilum is located echographically in the form of a “break” in the medial contour of the renal parenchyma, while when scanning from the anterior abdominal wall, at the top of the scan, an anteriorly located anechoic tubular structure is visualized - the renal vein, located behind the hypoechoic renal artery. The parenchyma is heterogeneous and consists of two layers: the cortex and the medullary (or the substance of the kidney pyramids). The morphological substrate of the renal cortex (kidney cortex) is predominantly the glomerular apparatus, convoluted tubules, interstitial tissue containing blood and lymphatic vessels, and nerves. The medullary substance contains loops of Henle, collecting ducts, ducts of Bellini, and interstitial tissue. The renal cortex is located along the periphery of the ultrasound section of the kidney with a thickness of 5–7 mm, and also forms invaginations in the form of columns (columnae Bertini) between the pyramids. In Fig. 19, 20 present a schematic representation of the parenchyma layers and a technique for measuring the thickness of the parenchyma elements. Often, Bertin's column extends quite far beyond the internal contour of the parenchyma into the central part of the kidney - into the renal sinus, dividing the kidney more or less completely into two parts. The resulting peculiar parenchymal “bridge,” the so-called hypertrophied column of Bertin, is the unresolved parenchyma of the pole of one of the kidney lobes, which merge during ontogenesis to form an adult kidney. This bridge consists of the cortex, columns of Bertin, and pyramids of the kidney. All elements of the bridge are normal parenchymal tissue without signs of hypertrophy or dysplasia.

Therefore, the name “hypertrophied Bertin column” existing in the literature does not reflect the morphological essence of the substrate, and, probably, the definition of Zh.K. Ena et al., who called this formation a parenchymal bridge. The echogenicity of the renal cortex is usually slightly lower or comparable to the echogenicity of the normal liver parenchyma. The kidney pyramids are defined as triangular-shaped structures with reduced echogenicity compared to the cortex. In this case, the top of the pyramid (pyramidal papilla) faces the renal sinus - the central part of the kidney section, and the base of the pyramid is adjacent to the parenchyma cortex, located along the periphery of the section (see Fig. 19). The renal pyramids have a thickness of 8–12 mm (the thickness of the pyramids is defined as the height of the triangular structure, the apex of which faces the renal sinus), although the normal size of the pyramids largely depends on the level of diuresis. Normally, the echographic differentiation of the cortex and pyramids is pronounced: the echogenicity of the cortical substance is significantly higher than the echogenicity of the pyramids of the kidney. Often this difference in echogenicity is the cause of a false-positive diagnosis of hydrocalycosis, when very dark, low-echogenicity pyramids are mistaken by novice ultrasound doctors for dilated cups. Modern histomorphological studies of the kidney parenchyma and their comparison with the echographic picture suggest that the pronounced echographic corticomedullary differentiation is due to a significant difference in the number of fat vacuoles in the epithelium of the tubular structures of the cortex and pyramids. However, it is impossible to explain the different echogenicity of the cortex and pyramids only by the different content of fat vacuoles in the epithelium of tubular structures, since it is known that the echogenicity of the kidney pyramids is high level diuresis is significantly lower than the echogenicity of the pyramids of the same kidney under normal conditions, while the number of fat vacuoles does not change depending on the level of diuresis. It is also impossible to explain the low echogenicity of the pyramids by the presence of fluid in the tubular structures, since the resolution of the ultrasound device under any conditions does not allow differentiating the lumen of the tubule and the fluid in it. It can be assumed that the low echogenicity of the medullary substance is associated with:

1) with a high content of glycosaminoglycans in the interstitial tissue, where most of the functional processes providing ion exchange, reabsorption of water and electrolytes, and urine transport occur; glycosaminoglycans are able to “bind” liquid, according to the authors of the hypothesis, “swelling and swelling very quickly”;

2) the presence of smooth muscle fibers in the interstitial tissue surrounding the excretory ducts of the renal papilla.

In children, the echogenicity of the cortex is significantly higher than in adults, which is explained by a more compact arrangement of the glomeruli and less interstitial tissue. Pyramids occupy a larger area than in adults. Morphometric studies have shown that in newborns the cortex and pyramids occupy about 90% of the kidney volume; in adults, the percentage decreases to 82%.

In the center of the echographic section of the kidney, a hyperechoic complex of oval or round shape (depending on the scanning plane) is determined, the renal sinus, the size and echogenicity of which varies largely depending on the age of the subject and his dietary habits.

If the echographic characteristics and interpretation of the image of normal parenchyma are generally accepted in medical practice and in scientific research, then the interpretation of the central echo complex varies significantly among different authors. In practical work, as well as in scientific articles of some authors, there is a semantic identification of the central echo complex and the renal collecting system. However, modern histomorphological and echographic correlations of a normal kidney have convincingly proven that the central echo complex is a summary reflection not of the collecting system, but of the entire set of elements of the renal sinus. By comparing anatomical and echographic data, it was established that it is the renal sinus, and not the pyelocaliceal system, as previously thought, that is the morphological substrate of the central echo complex.

Very little has been written about the renal sinus as an anatomical entity, although there is extensive medical research evidence describing various renal sinus pathologies. When an image is acquired, many conditions give a similar picture. Misdiagnosis may occur when a diagnosis is attempted without considering various possibilities.

So, the echogenicity of the central complex is determined, first of all, by the presence and amount of fatty tissue in the renal sinus. However, in addition to high-intensity reflections, the central echo complex contains small zones of reduced echogenicity and anechoic zones. For quite a long time it was believed that these zones are reflections of the elements of the collecting system. Data on the normal echographic dimensions of the pyelocaliceal system in adult subjects are extremely contradictory and sparse. Thus, in 1982, A. Deina reported on the “syndrome of echographic invisibility of the collecting system.” I.S. Amis calls dilatation of the collecting system any “splitting” of the collecting system by an echo-negative strip. K.K. Hayden, L.I. Svishuk assume that there is normally only a thin layer of fluid in the pyelocalyceal system. Moreover, the presence of expansion of the pelvis and calyx structures and their fusion in the form of a “tree” is, according to these authors, a sign of hydronephrosis. T.S. Hihashi, comparing data from echography, Dopplerography and excretory urography, came to the conclusion that the classification of hydronephrosis by P.Sh. Illenboden, who describes sonographically detected hydronephrosis by degree as a splitting of the central echo complex in the form of: a) a branchy tree structure, b) a lily structure, c) a clover structure, d) a rosebud-shaped structure, leads to a false-positive diagnosis of hydronephrosis. According to these authors, splitting of the central echo complex in the form of a tree corresponds to normal vascular structures, an echo-negative structure in the form of a lily corresponds to a normal pelvis or, possibly, an obstructive process, a structure in the form of a rosebud corresponds to the initial form of hydronephrosis, and a clover-shaped structure corresponds to severe hydronephrosis. At the same time, false-positive diagnosis of hydronephrosis occurred in 11%, false-negative – in 22% of cases. Quantitative estimates of the size of the normal pyelocalyceal system are not provided in the work of these authors. Although I. Hash tried to use the size of the pelvis as an index determining the degree of hydronephrosis, data defining the anteroposterior size of the pelvis as a differential diagnostic criterion for normal and pathological conditions was not given. F.S. Will considers the anteroposterior size of the pelvis to be 30 mm as the norm, which from our point of view is completely unacceptable. V.N. Demidov, Yu.A. Pytel, A.V. Amosov determines the normal anteroposterior size of the pelvis to be 1 – 2.5 cm. G.M. Imnaishvili believes that visualization of the calyces in the form of anechoic, rounded formations up to 5 mm in diameter is normally acceptable. The pelvis can be visualized as two hyperechoic linear structures extending towards the renal hilum.

Issues of normal echoanatomy of the kidney are sufficiently fully covered in foreign textbooks, monographs, articles and are not sufficiently covered in the domestic literature.

Kidney sizes, according to N.S. Ignashin, are 10-12 cm and 3.5 - 4.5 cm in a longitudinal section, 5-6 cm and 3.5 - 4.5 cm in a transverse section. The total thickness of the parenchyma is 1.2 - 2.0 cm in the middle segment, 2.0 – 2.5 cm in the region of the poles of the kidney. The normal kidney volume is 300 cm3. According to V.N. Demidov, kidney length 7.5 – 12 cm, width 4.5 – 6.5 cm, thickness 3.5 – 5 cm. According to M.P. Burykh and the specialists who carried out anatomical-echographic correlations, the length of the kidney is 10.41 + 1.3 cm, the width of the kidney is 5.45 ± 1.3 cm, and the thickness is 3.63 ± 0.5 cm.

The cut shape of a normal kidney in all projections is bean-shaped or oval. The contour of the kidney is usually smooth, and if there is preserved fetal lobulation of the kidney, it is wavy (this is a variant of the normal structure of the kidney). Quite often, a local bulging of the contour is normally detected in the area of the lateral edge of the kidney (in this case, the so-called “humpbacked” kidney is defined) or in the area of the edge of the renal sinus, which simulates a kidney tumor. These conditions are described as pseudotumors and are also variants of the normal kidney structure. One of the distinctive features of pseudotumor “bulges” of the parenchyma with preserved fetal lobulation of the kidney, in contrast to the tumor, is the preservation of parallelism of the outer and internal contours of the parenchyma, the preservation of the normal echostructure of the parenchyma.

In Fig. Figure 18 shows an echogram of a normal adult kidney.

Sonographic characteristics of the renal capsule and parenchyma of the normal kidney are generally accepted. Along the periphery of the ultrasound section of the kidney, a fibrous capsule is visible in the form of a hyperechoic, smooth, continuous structure 2–3 mm thick, then the parenchyma layer is determined. The renal hilum is located echographically in the form of a “break” in the medial contour of the renal parenchyma, and when scanning from the anterior abdominal wall, at the top of the scan, an anteriorly located anechoic tubular structure is visualized - the renal vein, located behind the hypoechoic renal artery. The parenchyma is heterogeneous and consists of two layers: the cortex and the medullary (or the substance of the kidney pyramids). The morphological substrate of the renal cortex (kidney cortex) is predominantly the glomerular apparatus, convoluted tubules, interstitial tissue containing blood and lymphatic vessels, and nerves. The medullary substance contains loops of Henle, collecting ducts, ducts of Bellini, and interstitial tissue. The renal cortex is located along the periphery of the ultrasound section of the kidney with a thickness of 5–7 mm, and also forms invaginations in the form of columns (columnae Bertini) between the pyramids. In Fig. 19, 20 present a schematic representation of the parenchyma layers and a technique for measuring the thickness of the parenchyma elements. Often, Bertin's column extends quite far beyond the internal contour of the parenchyma into the central part of the kidney - into the renal sinus, dividing the kidney more or less completely into two parts. The resulting peculiar parenchymal “bridge,” the so-called hypertrophied column of Bertin, is the unresolved parenchyma of the pole of one of the kidney lobes, which merge during ontogenesis to form an adult kidney. This bridge consists of the cortex, columns of Bertin, and pyramids of the kidney. All elements of the bridge are normal parenchymal tissue without signs of hypertrophy or dysplasia.

Therefore, the name “hypertrophied Bertin column” existing in the literature does not reflect the morphological essence of the substrate, and, probably, the definition of Zh.K. Ena et al., who called this formation a parenchymal bridge. The echogenicity of the renal cortex is usually slightly lower or comparable to the echogenicity of the normal liver parenchyma. The kidney pyramids are defined as triangular-shaped structures with reduced echogenicity compared to the cortex. In this case, the top of the pyramid (pyramidal papilla) faces the renal sinus - the central part of the kidney section, and the base of the pyramid is adjacent to the parenchyma cortex, located along the periphery of the section (see Fig. 19). The renal pyramids have a thickness of 8–12 mm (the thickness of the pyramids is defined as the height of the triangular structure, the apex of which faces the renal sinus), although the normal size of the pyramids largely depends on the level of diuresis. Normally, the echographic differentiation of the cortex and pyramids is pronounced: the echogenicity of the cortical substance is significantly higher than the echogenicity of the pyramids of the kidney. Often this difference in echogenicity is the cause of a false-positive diagnosis of hydrocalycosis, when very dark, low-echogenicity pyramids are mistaken by novice ultrasound doctors for dilated cups. Modern histomorphological studies of the kidney parenchyma and their comparison with the echographic picture suggest that the pronounced echographic corticomedullary differentiation is due to a significant difference in the number of fat vacuoles in the epithelium of the tubular structures of the cortex and pyramids. However, the different echogenicity of the cortex and pyramids cannot be explained only by the different content of fat vacuoles in the epithelium of tubular structures, since it is known that the echogenicity of the pyramids of the kidney at a high level of diuresis is significantly lower than the echogenicity of the pyramids of the same kidney under normal conditions, and the number of fat vacuoles depends on diuresis level does not change. It is also impossible to explain the low echogenicity of the pyramids by the presence of fluid in the tubular structures, since the resolution of the ultrasound device under any conditions does not allow differentiating the lumen of the tubule and the fluid in it. It can be assumed that the low echogenicity of the medullary substance is associated with:

2) the presence of smooth muscle fibers in the interstitial tissue surrounding the excretory ducts of the renal papilla.

The renal sinus is a specific anatomical structure that surrounds and includes the collecting system of the kidneys. It borders on the lateral side with the renal pyramids and cortical columns. The medial renal sinus communicates with the panephric space through the renal hilum. The elements of the renal sinus are lymphatic, nervous, renovascular structures surrounded by fatty and fibrous tissue. A decrease in the percentage of parenchyma in the kidney volume in an adult compared to a newborn occurs precisely due to an increase in the volume of the renal sinus, which occurs as a result of the “age-related” growth of renal sinus fiber. The adipose tissue of the renal sinus is practically absent in the newborn, which is echoographically manifested by the absence of reflected echo signals from the renal sinus or in a minimally expressed central echo complex in the form of a delicate, branched, weakly echogenic structure. In contrast to the adult kidney, the medullary layer is more pronounced, the central echo complex is represented by a branched structure that is smaller in area and echogenic. By the age of 10, the renal sinus is almost completely formed. Similar data were obtained from MR studies of the kidneys of healthy children (an intense signal on T 1-weighted images, corresponding to sinus tissue, appears in the age group of children over 10 years old. Normally, an age-related increase in the amount of renal sinus tissue is observed. In some cases, pathological proliferation of fiber (in 0.66 - 10% of cases) - sinus fibrolipomatosis. The most common sinus lipomatosis occurs after fifty years. It was found that the ratio of the anteroposterior size of the kidney to the anteroposterior size of the renal sinus in both kidneys in both males and females is in inverse correlation with age. No significant correlation with gender has been identified. In addition to age, the causes of lipomatosis can be: obesity, steroid therapy, Cushing's syndrome. Replacement fibrolipomatosis occurs more often as a result of severe renal atrophy against the background of urolithiasis. In such cases, stones are detected in 3/4 of patients. If echography reveals an increase in the central echo complex against the background of coral nephrolithiasis, then, as a rule, this is a consequence of replacing fibrolipomatosis against the background of urolithiasis and chronic pyelonephritis. On nephrotomograms, renal sinus lipomatosis cannot be distinguished from renal sinus cysts - there is a classic picture of elongated and curved calyx necks. Some studies provide observations of echo-negative formations in the projection of the renal sinus, allegedly associated with the process of renal lipomatosis. According to I.S. Amis, who analyzed the reasons for the discrepancies between echography and nephrotomography data, these errors are associated with incorrect interpretation of X-ray negative zones in the projection of the renal sinus during nephrotomography. This assumption was confirmed in similar cases with computed tomography and puncture. Renal echography helps distinguish renal sinus lipomatosis from cysts. With sinus lipomatosis, there is an increase and increased echogenicity of the renal sinus.

Quite curious are the data of T.Ch. Tzei et al. The study of the authors' data was undertaken with the aim of establishing the echographic dimensions of the normal renal pelvis in children and determining the correlation between its size and the presence of a particular renal pathology, as well as the dependence of the size of the pelvis on age. It was found that the upper limit of normal anteroposterior size in children is 10 mm, and only 1.7% of normal renal pelvis exceeded the size of 10 mm. Correlation analysis did not reveal statistically significant differences in the size of the renal pelvis in different age groups, although the average size values in the normal group and in the pathology group were statistically different (p Potential causes of false-positive diagnosis of hydronephrosis, according to T.C. Tzei and other authors, are: overdistension of the bladder, increased urine flow (under the influence of diuretics, contrast agents, diabetic polyuria, hyperhydration), atony of the pelvis during acute inflammation, cystic changes in the kidney, simulating hydronephrosis. The reasons for a false negative diagnosis are: dehydration, acute obstruction without dilatation, obstruction of the distal parts of the urinary tract, damage to the collecting system, incorrect interpretation of the normal image. To determine the capabilities of echography, pharmacoechography with a diuretic in the visualization of the collecting system, as well as to determine the echographic dimensions of the normal pelvis and calyces, we conducted studies in groups of healthy individuals under various drinking regimes and degrees of bladder filling. When comparing the echographic picture of the renal sinus in the B-mode and in the color Doppler mapping mode, it was found that under conditions of water deprivation (when examined on an empty stomach) and with an empty bladder, all echo-negative zones in the renal sinus corresponded to zones of detectable blood flow. Elements of the pyelocaliceal system in the form of an- or hypoechoic structures were not identified. Moreover, in the subgroup of people under 30 years of age, the largest echo-negative structures corresponded to the venous vessels of the renal sinus and had an average diameter of 5.6 + 1 mm, in the middle age subgroup (up to 50 years) - 4.9 ± 0.4 mm, in the older age group subgroup of persons venous structures were not so clearly visualized, and their average diameter was 3.8 ± 0.1 mm. Branches of the renal artery were typically identified as much smaller hypoechoic zones within the renal sinus. Almost all echo-negative zones corresponded to zones of detectable blood flow.

In a group of healthy individuals with a normal drinking regimen (1.5 liters of fluid per day) and average bladder filling (up to 250 ml), cup structures with a diameter of no more than 5 mm were visualized in 8% of the subjects.

In the third group of healthy individuals, a pharmacoechographic test with furosemide was used as a method of visualizing the pyelocaliceal system (PSS); At the same time, the possibilities of pharmacoechography in obtaining a clear echographic picture of the CLS were studied. The term “pharmacoechography” was introduced by A.V. Amosov and G.M. Imnaishvili in 1988. Pharmacoechography, as defined by these authors, is a study of urodynamics using diuretic drugs. medications under ultrasound control. Before the test, the authors determine the size of the pyelocaliceal system and assess the condition of the parenchyma. The patient is then given 20 mg of furosemide or bufenox at a dose of 2 ml of a 0.025% solution intravenously, followed by an ultrasound examination for 30 minutes or more. The effect of the drugs begins after 2 - 3 minutes and continues relatively a short time. The authors believe that with undisturbed passage of urine, the clarity of the image and the size of the cups and pelvis do not change after the administration of a diuretic. If the passage of urine is disturbed, if there are disturbances in urodynamics, ultrasound begins to reveal retention changes in the pyelocaliceal system.

In more recent works, pharmacoechography is used as a method of diagnosis and differential diagnosis of stenoses of the ureteropelvic segment to determine the degree of damage and the degree of reversibility of changes in obstructive nephropathy, for the purpose of differential diagnosis of true obstruction of the urinary tract in the fetus, diagnosis of renal sinus cysts. Magnitol is also used as a diuretic.

Our studies suggest the use of pharmacoechography as a way to visualize the pyelocaliceal system of the normal kidney. In this case, furosemide is administered intravenously or intramuscularly at the rate of 0.5 mg per kilogram of the patient’s weight against the background of high hydration (the subjects are asked to take 0.8 - 1.0 l of fluid an hour before the study). At intravenous administration The effect of the drug occurs “at the tip of the needle.” The pyelocaliceal system begins to be visualized as a hypoechoic tree-like structure, splitting the central hyperechoic echo complex. In this case, the role of a kind of contrast, allowing visualization of the CLS against the background of the fatty tissue of the sinus, is played by the fluid, which more completely fills the cavities of the collecting system. Pay attention to how the echographic picture of the renal hilum has changed after the administration of furosemide - three anechoic structures are already visualized in the renal hilum: the renal vein, the artery and the posterior pelvis. With the intramuscular route of administration, the average time to start imaging increases and is 10.2 ± 5.3 minutes.

Summarizing all of the above about the echoanatomy of a normal kidney, we emphasize the most important points:

– a normal kidney does not necessarily have an even, but always clear (due to the presence of a capsule) contour;

– assessment of the position of the kidney is carried out in relation to nearby organs, as well as in relation to bone landmarks (mainly the 12th rib);

– when assessing the echostructure and echogenicity of the kidney, the presence or absence of corticomedullary differentiation, differentiation of the parenchyma and the renal sinus is determined, the echogenicity and echostructure of each element of the parenchyma and renal sinus are assessed;

– the central echo complex of the kidney section is a total reflection of the elements of the renal sinus, while the hyperechoic component of the complex is caused primarily by the fatty tissue of the renal sinus; hypo- and anechoic formations when examined on an empty stomach are due to the presence of vascular elements;

Kidney structure

The kidneys are located retroperitoneally in the lumbar region at the level of the last two thoracic and first two lumbar vertebrae. The right kidney is usually 1-2 cm lower than the left.

The kidney parenchyma consists of a cortex and pyramids. The renal columns (Bertini's columns) between the pyramids consist of the cortex. The pyramid and the cortical substance covering it form the renal lobule. At the top of the pyramid, the openings of the papillary tubules open.

The renal sinus contains the pyelocaliceal complex (PCC), vessels, nerves, connective tissue and fat. The small cup sits on the top of the pyramid like a breast pump on the nipple. Urine actively flows into the small and large calyces → renal pelvis → ureter → bladder → urethra.

Click on pictures to enlarge.

Kidney ultrasound

A 2.5-7.5 MHz convex sensor is used. If a pathology is suspected, the study is carried out with a full bladder when the urge to urinate appears. After urination, the kidneys are examined again.

We are interested in the location, size, echogenicity, echostructure of the kidneys, as well as the patency of the urinary tract. For more information, see how to assess kidney size in children and adults.

Bladder and distal ureter on ultrasound

With the patient lying on his back, we remove the bladder in the suprapubic region. Assess bladder fullness and distal section ureters. Normally, the distal ureter is not visible. A ureter more than 7 mm in diameter is a megaureter.

Drawing. Ultrasound shows an enlarged distal ureter (1, 2, 3). About ureterocele (3) see in more detail.

Echogenicity of the kidneys

With the patient in the supine position, along the midclavicular and anterior axillary line, we bring out the right kidney adjacent to the liver, and the left kidney near the spleen. Assess the echogenicity of the kidneys. The renal cortex is normally iso- or hypoechoic in relation to the liver and hypoechoic in relation to the spleen.

Drawing. The echogenicity of organs is compared on one section. Ultrasound shows a normal kidney adjacent to the liver (1) and spleen (2). In children under 6 months of age, the renal parenchyma may normally be hyperechoic compared to the liver (3).

Kidney shape on ultrasound

To view the upper pole of the kidney, ask the patient to take a deep breath. The shape of the kidney is bean-shaped - convex on the lateral side and concave on the medial side. An embryonic lobulated kidney, as well as a humpbacked left kidney, are considered as a variant of the norm.

Drawing. On ultrasound (1) and CT (2, 3) the contour of the kidneys is wavy. In the embryo, the kidney develops from separate lobules that fuse as they grow. The lobulated structure of the kidneys is clearly visible in the fetus and newborns; in isolated cases, it persists in adults.

Drawing. You can find a humpbacked left kidney - a convex, uneven outer contour due to hypertrophy of the parenchyma in the middle third of the kidney. It is believed that the “hump” is formed in the fetus under pressure from the lower edge of the spleen.

Drawing. Scanning from the anterior abdominal wall allows us not to miss the isthmus between the kidneys. The isthmus in front of the spine is evidence of fusion of the kidneys - a horseshoe kidney. See variations of the anatomy of horseshoe kidneys.

Video. Horseshoe-shaped kidney on ultrasound

Echostructure of the kidneys

In a normal kidney, the pyramids are hypoechoic, the cortex and columns of Bertini are isoechoic to each other. In the sinus there is normally an invisible PCL, hyperechoic connective and adipose tissue, hypoechoic vessels and the apices of the pyramids.

When pyramids, cortex, and renal columns are distinguished, the echostructure of the renal parenchyma is not changed. If they are not visible, then the echostructure is changed due to the lack of clear cortical-cerebral differentiation.

Drawing. Ultrasound shows a kidney with an unchanged echostructure: hypoechoic in relation to the liver, cortical layer and columns of Bertini, almost anechoic pyramids, hyperechoic sinus.

Drawing. In 37% of healthy newborns, the symptom of “white pyramids” is detected by ultrasound on the first day of life. Precipitation of Tamm-Horsfall protein and uric acid causes reversible tubular obstruction. By 6 weeks of life it goes away without treatment.

Drawing. Ultrasound of a healthy kidney: along the base of the pyramids (corticomedullary junction) linear hyperechoic structures with a hypoechoic track in the center are identified. These are arcuate arteries, which are mistakenly regarded as nephrocalcinosis or stones.

Video. Arc-shaped arteries of the kidney on ultrasound

Drawing. On ultrasound, the lower pole of the kidney is separated by a hyperechoic fibrous bridge; pelvis of the lower segment 7 mm. This is a variant of the normal structure of the kidney. The kidney may be deformed, so its size and length are slightly smaller than the opposite one. A slight expansion of the pelvis under the bridge persists for life.

Video. Ultrasound shows a fibrous bridge in the kidney (structural variant)

Sometimes Bertini's column cuts into the central part of the kidney, dividing it completely or incompletely into two parts. Such a parenchymal bridge is the parenchyma of the pole of one of the embryonic lobules, which fuse to form a kidney; consists of bark, pyramids, columns of Bertini - all elements without signs of hypertrophy or dysplasia. The term hypertrophy of Bertini's column does not reflect the morphology of the structure; it is more accurate to consider this formation as a parenchymal bridge.

Drawing. On ultrasound, a round formation divides the renal sinus into two segments with a common pelvis; interlobar arteries go around the formation; the echogenicity and intensity of the vascular pattern inside is close to the cortical zone. Conclusion: Hypertrophy of Bertini's column or incomplete parenchymal bridge. This is a variant of the normal structure of the kidney. The term “incomplete doubling of the maxillofacial area” is incorrect, because an incomplete parenchymal bridge is not a sign of doubling of the PC.

Drawing. On ultrasound, the renal sinus is separated by a complete parenchymal bridge (1, 2). In such cases, excretory urography will help to distinguish between doubling of the kidney from hypertrophy of the Bertini column. The double kidney is covered with a common fibrous capsule. Complete duplication implies the presence of two pelvises, two ureters and two vascular bundles. An incompletely doubled kidney (3) is fed by one vascular bundle, the ureter can be doubled at the top and flow into the bladder with one or two mouths. Doubling of the PCL and ureters is a risk factor for the development of pathology (pyelonephritis, hydronephrosis, etc.).

Drawing. On ultrasound, the renal sinus is wide, with a heterogeneous echostructure (1, 2). Against the background of hyperechoic fat, a hypoechoic focus of a rounded shape (2), with CDI, interlobar vessels pass through the hypoechoic zone without displacement (3) - this is hypoechoic fat. In obesity, sinus lipomatosis can be mistaken for parenchymal atrophy.

The ureter, minor and major calyces are normally not visible on ultrasound. There are three types of location of the pelvis: intra-, extrarenal and mixed (partly inside the kidney, partly outside it). With an intrarenal structure, the lumen of the pelvis is early age up to 3 mm, at 4-5 years old - up to 5 mm, in puberty and in adults - up to 7 mm. For extrarenal and mixed types of structure - 6, 10 and 14 mm, respectively. With a full bladder, the pelvis can increase up to 18 mm, but 30 minutes after urination it is reduced.

Drawing. Regardless of the filling of the bladder, ultrasound shows the pelvis of mixed (1, 2) and extrarenal (3) locations.

Drawing. In children under 1 year of age, the sinus of the kidney is poorly defined on ultrasound, anechoic pyramids can be mistaken for an extended PCL (1). On ultrasound at the hilum of the kidney, the linear hypoechoic structure looks like an enlarged pelvis (2); with color circulation it is clear that these are vessels (3).

Abnormalities in the location of the kidneys on ultrasound

Anomalies in the location of the kidneys occur when there is a violation of the movement of the primary kidney from the pelvis to the lumbar region. Almost always the shape of the kidney is changed, and the gate is open forward.

In thoracic dystopia, the kidney is usually part of a diaphragmatic hernia. With lumbar dystopia, the pelvis is located at the level of L4, with iliac dystopia - L5-S1. The pelvic kidney is located behind or just above the bladder. With cross dystopia, the ureter flows into the bladder in the usual place, and the kidney is displaced contralaterally.

Drawing. Kidney dystopia in relation to the skeleton: thoracic on the right (1), bilateral lumbar (2), pelvic on the left (3), lumbar on the right and pelvic on the left (4), lumbar of the double left kidney (5), cross (6).

Drawing. Dystopia of the kidneys in relation to each other and their fusion with each other: fusion of the upper ends (1), lower ends and doubling of the left kidney (2), the middle parts of the pelvic-dystopic kidneys (3), the lateral parts of the pelvic-dystopic kidneys (4), different ends (5), at an angle (6).

Drawing. On ultrasound, the renal bed on the left is empty (1). Both kidneys are located on the right, fused at the poles (2, 3). Conclusion: Anomaly of the relative position of the kidneys - I-shaped double right kidney.

Drawing. Ultrasound in the pelvis (bladder - acoustic window) reveals kidneys connected by a narrow isthmus (1, 3); parenchymal differentiation is preserved, and blood flow can be traced to the capsule (2, 3). Conclusion: Anomaly of the relative position of the kidneys - fusion of the lower poles of the pelvic-dystopic kidneys.

Kidney mobility on ultrasound

Let's mark the level of the upper pole of the kidney on the skin with the patient lying on his stomach and standing. Before re-measuring, ask the patient to jump.

Normally, when inhaling, the kidneys drop by 2-3 cm. In adults, we can speak of pathological mobility of the kidney if on an ultrasound in a standing position the kidney moves by 5 cm. In children, a displacement of 1.8-3% of height indicates excessive mobility, a displacement >3% is an indirect sign of nephroptosis. Nephroptosis is determined by x-ray - this is a movement of the kidney more than 2 times the height of the vertebral body.

How to distinguish nephroptosis from dystopia on ultrasound? Normally, the VA originates from the aorta immediately below the SMA, in lumbar dystopia - near the bifurcation of the aorta, in pelvic dystopia - from the iliac artery.

Drawing. With pelvic dystopia on intravenous urography in the supine position, the ureter is short, the kidney is in the pelvis (1, 2). With nephroptosis, intravenous urography in the supine position reveals the kidney in a typical place (3); in the standing position, the kidney is significantly lowered (4).

Take care of yourself, Your Diagnosticer!

What does hyperechoic pyramids mean?

Symptoms of hyperechogenicity

Types of hyperechoic inclusions

Structure and purpose of parenchyma

Cortical and medulla layers

Glomeruli and urine formation

Parenchyma thickness at different ages

Column Bertini

Parenchymal bridge

Regeneration ability

Diffuse changes and echogenicity

Syndrome of hyperechoic pyramids of the kidneys

Typical symptoms that cause kidney problems

Symptoms associated with kidney disease

Types of hyperechoic inclusions and diagnosis

Website about kidney diseases

Therapeutic measures and prevention

Necessary treatment

Clinical manifestations

Concepts - hyperechogenicity and acoustic shadow?

Educational video of normal kidney ultrasound

Biscuit bud

Quantity anomalies

Double kidney

Paired kidney

Abnormality of the renal parenchyma

Agenesis

Aplasia

Hypoplastic kidney

Accessory (third) kidney

Anatomical variations of the normally functioning kidney

Kidney with oval-convex uneven outer contour

Uneven lobulated kidney

Kidney with an isolated area of ​​hypertrophy of the parenchyma inside

Polycystic kidney disease

Multicystic dysplasia

Solitary cyst

Dermoid cysts

Multilocular cyst

Sponge bud

Megacalycosis (renal calyx dysplasia)

Calyceal diverticulum

Megaureter

Ureterocele

Renal vascular abnormality

Medical journal, publications

Difficulties and errors in ultrasound and x-ray diagnostics of renal pseudotumors

MySono-U6

Introduction

Materials and methods

Research results

Discussion

conclusions

Literature

MySono-U6

Publications on the topic

3.1. Kidneys

Kidney structure

Kidney ultrasound

Bladder and distal ureter on ultrasound

Echogenicity of the kidneys

Kidney shape on ultrasound

Video. Horseshoe-shaped kidney on ultrasound

Echostructure of the kidneys

Video. Arc-shaped arteries of the kidney on ultrasound

Video. Ultrasound shows a fibrous bridge in the kidney (structural variant)

Abnormalities in the location of the kidneys on ultrasound

Kidney mobility on ultrasound

Video. Kidneys at an ultrasound lecture by Vladimir Izranov

Kidney with an isolated area of hypertrophy of the parenchyma inside