An examination, including ultrasound of the renal vessels, is aimed at recognizing the features of the location of veins, arteries and their diameter. Such diagnostic method allows you to determine the speed of blood flow. This happens due to the work of the Doppler effect, an Austrian physicist whose name became the basis for the name of a specific procedure - Dopplerography of renal vessels.
In certain cases, it is necessary to undergo an ultrasound examination of the kidney vessels to obtain a picture of blood flow in the organ.
The essence of the method
The method of ultrasound scanning of renal vessels is based on ultrasonic waves that are reflected from red blood cells present in human blood. After their reflection, the waves are recorded by a special sensor of the main apparatus and converted into electrical impulses. Only after this can the doctor examine the overall picture of the body’s condition.
All converted pulses are displayed on the device monitor in graphic format and color photographs. They give a detailed idea of the state of the blood flow. Main feature This research method makes it possible to monitor the activity of the organ and its surrounding vessels in real time.
What does a duplex scan of the renal arteries show?
Doppler ultrasound of the renal arteries guarantees the ability to monitor blood flow during spasm, any narrowing or even thrombosis. A correctly conducted analysis helps to compile a picture of possible pathological processes during the onset of the disease. The study will be especially useful in cases where the disease is asymptomatic due to early stage or after a series therapeutic measures to confirm the emerging dynamics of the patient’s recovery. Painless duplex scanning of the renal arteries also helps in assessing:
- architectonics of the problem area (structure, type, location and volume of the affected area);
- functionality (indicator of blood resistance).
Advantages and disadvantages
Main positive quality Ultrasound of the renal arteries using a Doppler sensor makes it possible to immediately receive the result along with an initial transcript from the specialist conducting the examination immediately upon completion of the examination. At the same time, the final diagnosis of the patient must still be made by the attending physician after studying the results obtained and based on incoming complaints from the person who applied.
Ultrasound of renal vessels according to the Doppler principle does not require injections, which is very comfortable for the patient. The method based on the Doppler effect does not involve any injection interventions, which makes it comfortable for the patient, as safe and painless as possible. In addition, this option for studying the problem is considered a relatively budget version of execution compared to other variations in the context of visualizing a possible disease.
From the point of view of its effect on the body, kidney Doppler has no contraindications, since it is not used in its work ionizing radiation. According to experts, it is unlikely that it will be possible to cope with the examination of soft tissues more effectively, because even the most advanced X-ray machine is not capable of producing a clear image vascular network. It is much more convenient to use Doppler angiography of the organ, which will confirm the preliminary diagnosis or refute the presence of problems in the kidney.
Indications for research
Ultrasound Dopplerography is prescribed by the attending doctor in case of numerous suspicions, since it is with its help that a number of both recently formed pathologies and chronic diseases that do not allow a person to feel fully long years. The most common reasons for prescribing a Doppler scan are:
- colic;
- discomfort in the lumbar region;
- swelling;
- diseases of the cardiovascular and endocrine areas;
- toxicosis in pregnant women in late stages;
- chronic diseases, which are associated not only with this organ, but also bladder(used to confirm whether it is normal).
Diagnostics can be prescribed even for children who are suspected of having vesicoureteral reflux. If one of the parents has problems with the kidney part, the children will be sent for examination to exclude all possible anomalies in this area that are transmitted at the genetic level from mom or dad.
Preliminary preparation
If the patient wants to get the most correct answer from the analysis, he will need to carefully prepare, starting with getting rid of the constantly accumulating gases in the intestines. They may be the reason why performing an ultrasound of the kidneys with Dopplerography will be difficult from the visual side of the issue. To avoid this, you need to follow a few simple tips on preparation:
- exclude vegetables and fruits, cabbage in any form, baked goods and other baked goods, legumes, juices, soda and milk from the diet a couple of days before the target date;
- according to the doctor’s instructions, you can take medications from the enterosorbent group, but keeping an eye on possible chronic diseases like diabetes or hypertension;
- Schedule a kidney vascular test for the first half of the day so you can go to the clinic on an empty stomach.
If for some reason it was not possible to schedule an examination in the morning and it was postponed to the afternoon, then a light breakfast is allowed. But in this case, the difference between eating and going directly to the doctor should be at least 6 hours. It is not recommended to go to an ophthalmologist after a colonoscopy, since there will be a lot of air in the intestines, making thorough visualization difficult.
Methodology
Ultrasound of the kidney vessels does not cause discomfort to the person and does not harm health. Modern examination of renal vessels with Doppler is not particularly difficult. At the appointment, the patient will be asked to undress to the waist level and remove jewelry in the area where the actual examination will be performed. After this, the person will be asked to lie down on the couch for comfort.
In order for the renal arteries to be truly visible on the monitor, the doctor must ensure close contact between skin and the device sensor. For this, a special gel is used that does not pose any toxic danger. Only after this the diagnostician begins the actual procedure, slowly moving the sensor across the skin.
During the diagnostic process, a person can hear different sounds, which come from the speakers of the device. They should not be scared, as this is a normal situation. In this way, the body reacts to changes in blood flow indicators. But if a sharp, high-pitched sound is heard from the speaker of the device, this may indicate a blockage of the blood passage.
The information obtained from Doppler ultrasound is entered into an electronic database, and a copy is given to the person seeking help so that he can pass it on to the attending physician. Upon request, a person can be given photographs created on thermal paper. They will show detected deviations and problem areas, for example, if the size of a vein section does not meet the standards.
In general, Doppler ultrasound of the renal arteries takes no more than half an hour. At the end of the event, the gel is wiped off the skin with a regular napkin, and the person can go home, to work, or immediately to an appointment with a specialized specialist to get an answer. possible diagnosis. He will not feel any discomfort and does not need further observation.
The main goal of Dopplerography (duplex scanning) of the renal arteries is to exclude critical stenosis (compression) of the renal arteries. Accurate information about the state of the local vascular network increases the effectiveness of treatment.
Thanks to ultrasound, the doctor will be able to assess the blood flow in the vessels supplying the kidneys - whether there are pathologies, and if there are any, at what stage of development they are.
Based on the data obtained, it is possible to discard false diagnoses that could have been made without an ultrasound examination and resolve the issue of the degree of inevitability surgical treatment and prescribe the optimal treatment package without surgery.
How is renal artery duplex performed?
The process is as follows:
- An ultrasonic signal comes from the sensor and is directed to the area under study;
- all blood elements are in constant motion, while they are able to reflect an ultrasound signal;
- the reflected signal is processed by a special computer program;
- the output is a color image with a clear visualization of the blood supply vessel;
- Based on the results of the study, the doctor draws conclusions - how well the kidney is supplied with oxygen through the blood and nutrients, whether there are seals in the vascular passages or the threat of their occurrence.
In what case is an examination prescribed?
The majority of patients referred for duplex scanning of the renal arteries are people:
- with persistent hypertension that does not respond to antihypertensive drugs. Doctors are especially concerned about the increased arterial pressure in young people - there is a suspicion of pathology in the area of the renal vasculature;
- who have a predisposition to stenosis, thrombosis, vascular ruptures, and the development of aneurysms;
- who is undergoing any kidney surgery;
- suffering from diabetic nephropathy;
- under the supervision of an oncologist with suspected lesions in the area of the renal arteries.
Today, the corresponding equipment is available in almost all clinics, hospitals and clinics. also in Lately The branch system of medical consultation centers is widely developing.
Preparing for duplex scanning
To examine the kidneys and blood supplying arteries, preparatory measures are necessary to reduce gas formation in the intestines. For this:
- a few days before the procedure, exclude fatty foods, dairy products from the diet, confectionery, fruits and vegetables (especially legumes in any form, cabbage);
- people with increased flatulence are recommended to take espumisan, smecta, enterosgel or Activated carbon(all these substances are adsorbents);
- stop using it for a few hours chewing gum, as well as smoking;
- You should come for dopleography on an empty stomach (more precisely, eating should occur no less than 8-9 hours before the study).
How the examination takes place:
- During the procedure, it is possible to change the patient's position - lying on his side (lateral access), on his stomach (posterior access), on his back (anterior and posterolateral access), standing (taking into account the individual structure of the urinary system);
- they expose the lower back, where a special gel is applied (it improves the quality of the signal between the skin and the sensor);
- sometimes the patient is asked to do deep breath and hold your breath (usually this happens in obese patients);
- the whole procedure lasts no more than half an hour;
- no discomfort - immediately after the scan is completed, the patient returns to his usual lifestyle.
Contraindications and precautions
Duplex examination is completely safe. Even pregnant women and small children can undergo it. The exception is patients with pronounced pain syndrome with large diameters of the aneurysm of the abdominal aorta or its branches.
If there is a suspicion of possible complications, the issue of dopleography is resolved individually:
- most often the procedure is cancelled;
- the study can be carried out if the specialist has high-quality ultrasound equipment at his disposal (which can reduce the duration of the procedure);
- the study is permissible if the diagnostician is highly qualified and is able to examine the patient quickly, accurately and with high-quality results.
Special approach in non-standard cases:
- there may be tumors, abscesses, cysts and other formations in the retroperitoneal space - the diagnostician will have to make do with a posterolateral approach (the patient lies on his side);
- the small diameter of the vessel and its large depth complicate the examination process (longer work will be required; with low-class equipment, the quality of the result is questionable).
Research results
It is very important how correctly the ultrasound report is interpreted. What should be revealed as a result of dopleography:
- anatomical location of arteries;
- places of origin of additional branches;
- state of blood flow in the vessel;
- elasticity of the vessel wall;
- deviations in the structure of the blood supply;
- condition of the vascular wall for ruptures, aneurysms, thinning, thickening;
- when the arteries are blocked or narrowed, it is revealed whether the cause is external factor(tumors, abscesses in fatty tissue, hematoma) or internal (atherosclerotic plaques, air embolus, thrombus).
Duplex scanning It is not difficult to pass through the renal arteries. And this must be done if there is evidence.
It should be remembered that the quality of the results depends on the experience of the specialist and on the quality of the diagnostic equipment (the higher it is, the more sensitive the sensors and the higher the accuracy of the data obtained).
Doctor Ginzburg L.Z. about preparation: to obtain highly informative data by ultrasound, it is still better to prepare - 3 days of a slag-free diet and use sorbents to reduce intestinal carbonation. Gases significantly reduce visualization during renal ultrasound.
Doppler ultrasound of the renal vessels (USDG) is a diagnostic method that can detect changes in blood flow. It is based on the Doppler effect. The meaning of this effect is the reflection of ultrasonic waves from red blood cells, which helps to visualize the condition of the vessels from the inside and evaluate their work. Ultrasound of the renal arteries with Doppler allows specialists to diagnose the state of blood flow in the renal vessels .
This is important because the most important function of the kidneys, excretory, directly depends on the state of blood flow.. Doppler ultrasound helps evaluate:
- the degree of damage to the vascular walls due to atherosclerosis, thrombosis;
- (atherosclerotic plaques, thrombosis);
- blood flow parameters (speed, volume);
- lumen of blood vessels (stenosis, spasms);
- the effectiveness of the prescribed treatment.
Indications for research
Ultrasound scanning of renal vessels is prescribed by a nephrologist for many kidney disorders. There are certain symptoms and conditions that indicate possible availability Kidney diseases that are indications for this ultrasound examination:
- Lower back pain.
- Swelling of the legs, face.
- Difficulty urinating.
- Increased blood pressure.
- Changes in general analysis urine (UAM): presence of blood (red blood cells), protein, increased number of leukocytes, change in density.
- Attacks of renal colic.
- Late toxicosis during pregnancy.
- Bruises in the lumbar region.
- Acute and chronic kidney diseases.
- Systemic diseases ( diabetes, vasculitis).
- In preparation for kidney surgery.
- If a tumor is suspected.
It is worth noting that contraindications and harmful effects On a person, ultrasound of the kidney vessels does not have.
The only drawback this method– difficulty in assessing and examining small vessels kidney
Therefore, to clarify the diagnosis, angiography (CT, MRI) is additionally performed. Obstacles may also arise in the presence of areas of calcification that occur in vessels due to atherosclerosis.
How to prepare for the echographic method with Doppler
In order for the ultrasound to be as informative as possible, it is necessary to take a responsible approach to preparation. The most an important condition for Doppler ultrasound is to reduce gas formation in the intestines. This allows for better visualization of the kidneys.
The following activities are carried out:
- A few days before the ultrasound, the patient needs to follow a diet. Products that contribute to increased gas formation are excluded from the diet: baked goods, cabbage in any form, legumes, raw fruits and vegetables, carbonated drinks, confectionery.
- These days, the doctor prescribes enterosorbents (activated carbon, espumizan, enterosgel, sorbex) 2 capsules 1-3 times a day as preparation.
- Ultrasound must be performed on an empty stomach. You should not drink or take medications before the test. If the procedure is scheduled after lunch, then the interval between last appointment food and ultrasound should be at least 6 hours. IN exceptional cases the interval can be reduced to 3 hours (severely ill patients).
It is impossible to perform an ultrasound scan of the vessels of the kidneys and their arteries after the following procedures: fibrogastroscopy, colonoscopy. After them, air enters the intestines, which makes it difficult to examine blood vessels and diagnose internal organs.
Survey methodology
Dopplerography of the kidneys is a gentle and comfortable procedure for the patient. It does not cause discomfort and is painless.
The patient undresses to the waist and takes a sitting or lying position on his side. The doctor applies a contact gel to the area being examined so that there is no layer of air between the sensor and the skin, this ensures maximum contact of the sensor with its surface. Then the doctor moves the sensor along the skin in the projection of the location of the kidneys and evaluates the resulting images. The results are recorded on paper and in photographs.
The whole procedure takes no more than 30 minutes.
At the end, the doctor issues a conclusion - a protocol, which contains the following information:
- organ shape (normally bean-shaped);
- outer contour (clear, even);
- capsule structure (hyperechoic, thickness up to 1.5 mm);
- relative position of organs ( right kidney slightly below the left);
- comparison of sizes (buds are the same size or the difference is no more than 2 cm);
- mobility of the organ (during breathing up to 2-3cm);
- anterior-posterior size (no more than 15mm);
- resistance index of the main artery (in the hilum area about 0.7, in the interlobar arteries from 0.36 to 0.74);
- developmental anomalies and vascular neoplasms are excluded;
- the anatomical location of the vessels and the origin of additional branches;
- condition of the vascular wall (thickening, thinning, aneurysms, ruptures);
- the state of the lumen of the vessel (if narrowing occurs, the reasons are determined);
- the resistance index is measured in the middle, terminal and proximal sections of the artery (a large difference in the indices in both kidneys indicates a violation of blood flow);
- The size and structure of the adrenal glands and the structure of the perinephric fiber are assessed.
Indicators and norms of artery trunks and their blood flow
Duplex and triplex mode of visualization of vessels and arteries (photo)
Let us present some norms of renal vessels during Doppler ultrasound kidneys in conclusion:
Normal artery diameter:
- main trunk – 3.3-5.6 mm;
- segmental arteries – 1.9-2.3 mm;
- interlobar arteries – 1.4-1.6 mm;
- arcuate arteries – 0.9-1.2 mm.
Systolic blood flow velocity in the arteries of the kidney:
- main trunk – 47-99 cm/sec;
- interlobar arteries – 29-35 cm/sec.
Diastolic arterial blood flow velocity:
- main trunk – 36-38 cm/sec;
- interlobar arteries – 9-17 cm/sec.
Benefits of Sonography
All of the advantages of the Doppler ultrasound method listed below help the doctor quickly make decisions about the necessary methods treatment. This is especially important when there is a question of surgical intervention.
- Non-invasive (no needle or injection).
- Get results quickly.
- Allows you to identify pathology at the time of examination.
- Makes it possible to examine soft tissues.
- No ionizing radiation is used during the procedure.
- Availability.
To summarize, we can say that with the help of vascular ultrasound, an experienced ultrasound diagnostic doctor can quickly and easily diagnose most pathological conditions organ. The examination takes a minimum of time, has no contraindications, is absolutely painless and harmless.
Ultrasound of the renal arteries- This ultrasonography, modern method diagnostics aimed at identifying various pathologies kidneys and genitourinary system. As a result of this procedure, the condition of the kidney and its vessels can be assessed. Modern medicine suggests starting kidney diagnostics with ultrasound. The procedure is completely painless and does not require complex preparation.
Indications for the study
Ultrasound of the renal arteries, indications:
Pain in the lumbar region,
- abnormalities in urine analysis, - renal colic,
- bruises and kidney injuries,
- systematic increase in pressure,
- transplanted kidney,
- preventive examination,
- diagnosis of neoplasms,
- chronic and acute specific and nonspecific inflammation of the kidneys.
Preparation for ultrasound of the renal arteries
If you have been assigned Ultrasound of the renal arteries, preparation should be an integral part of this procedure.
In the morning, before the procedure, it is not recommended to drink more than 100 ml of water, or use diuretics. If you are overweight or increased gas formation, then a few days before the ultrasound it is better to exclude milk, brown bread, raw fruits and vegetables from the diet. As you can see, ultrasound does not require complex preparation, but before the procedure itself it is better to consult with an experienced doctor. It is most convenient to undergo a consultation and examination in a private center, because the procedure will be carried out here the best specialists V short time. You won't have to wait long in line to get an ultrasound.
Immediately before the procedure, a special gel is applied to the skin, which ensures better glide of the device over the body, eliminating air between the skin and it. It does not cause allergies and is easily washed off from both skin and clothing.
Conducting research
Ultrasound of the renal arteries– the procedure is completely painless and harmless. It can be performed both standing and lying down. The kidneys are perfectly visualized on the screen without any special preparation.
The procedure is carried out using a special transducer that sends ultrasonic waves high frequency. When the device is placed on the stomach, supersonic waves reach the tissues and organs, then the waves are reflected from the organs and enter the transducer. The picture is then displayed on the screen.
Most patients undergo ultrasound without any preparation at all. In case of poor visualization, for example in patients suffering from flatulence or obesity, the study is performed while holding the breath at maximum exhalation.
At Ultrasound of the renal arteries is normal– narrowing of the artery up to 5 mm.
After the ultrasound, no special rules need to be followed. You can return to your normal diet, of course, unless your doctor prescribes a diet for you. An ultrasound of the kidneys will take you only 3-5 minutes with a standard examination and 15-20 minutes with a Doppler examination. Results are usually ready within 10-15 minutes after completion of the study.
The structure of the kidney vessels
The renal arteries arise from the abdominal aorta just below the superior mesenteric artery - at the level of the second lumbar vertebra. Anterior to the renal artery is the renal vein. At the hilum of the kidney, both vessels are located anterior to the pelvis.
The RCA passes behind the inferior vena cava. The LPV passes through the “tweezers” between the aorta and the superior mesenteric artery. Sometimes a ring-shaped left vein is found, in which case one branch is located in front and the other behind the aorta.
Click on pictures to enlarge.
To study the vessels of the kidney, a 2.5-7 MHz convex sensor is used. The patient is positioned supine, the sensor is placed in the epigastrium. Assess the aorta from the celiac trunk to the bifurcation in B-mode and color flow. Trace the course of the RAA and LPA from the aorta to the renal hilum.
Drawing. In the CD mode, on the longitudinal (1) and transverse (2) sections, the RAA and LPA extend from the aorta. The vessels are directed to the gates of the kidney. Anterior to the renal artery is the renal vein (3).
Drawing. The renal veins drain into the inferior vena cava (1, 2). The aortomesenteric “tweezers” may compress the left ventricular vein (3).
Drawing. At the hilum of the kidney, the main renal artery is divided into five segmental ones: posterior, apical, superior, middle and inferior. The segmental arteries are divided into interlobar arteries, which are located between the pyramids of the kidney. The interlobar arteries continue into the arcuate → interlobular → glomerular afferent arterioles → capillary glomeruli. Blood from the glomerulus drains through the efferent arteriole into the interlobular veins. The interlobular veins continue into the arcuate → interlobar → segmental → main renal vein → inferior vena cava.
Drawing. Normally, with CDK, the renal vessels are traced to the capsule (1, 2, 3). The main renal artery enters through the renal hilum; accessory arteries from the aorta or iliac artery may approach at the poles (2).
Drawing. On ultrasound 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
Doppler of renal vessels is normal
The normal diameter of the renal artery in adults is 5 to 10 mm. If diameter<4,65 мм, вероятно наличие дополнительной почечной артерии. При диаметре главной почечной артерии <4,15 мм, дополнительная почечная артерия имеется почти всегда.
The renal artery should be assessed at seven points: at its exit from the aorta, in the proximal, middle and distal segments, as well as the apical, middle and lower segmental arteries. We evaluate peak systolic (PSV) and end-diastolic (EDV) blood flow velocities, resistivity index (RI), acceleration time (AT), acceleration index (PSV/AT). See more details.
The normal spectrum of the renal arteries has a pronounced systolic peak with antegrade diastolic flow throughout the cardiac cycle. In adults, the normal PSV on the main renal artery is 100±20 cm/sec, EDV is 25-50 cm/sec, in young children PSV is 40-90 cm/sec. In segmental arteries, PSV drops to 30 cm/sec, in interlobar arteries to 25 cm/sec, in arcuate arteries to 15 cm/sec and interlobular arteries to 10 cm/sec. RI at the renal hilum<0,8, RI на внутрипочечных артериях 0,34-0,74. У новорожденного RI на внутрипочечных артериях достигает 0,8-0,85, к 1 месяцу опускается до 0,75-0,79, к 1 году до 0,7, у подростков 0,58-0,6. В норме PI 1,2-1,5; S/D 1,8-3.
Drawing. Normal spectrum of renal arteries - high peak systolic, antegrade diastolic flow, low peripheral resistance - RI normal<0,8.
Drawing. The spectrum of renal vessels in newborns: renal artery - pronounced systolic peak and antegrade diastolic flow (1); high resistance in the intrarenal arteries is considered normal for newborns - RI 0.88 (2); renal vein - antegrade flow with a constant speed throughout the entire cardiac cycle, minimal respiratory fluctuations (3).
Doppler for renal artery stenosis
Renal artery stenosis can be found in atherosclerosis or fibromuscular dysplasia. With atherosclerosis, the proximal segment of the renal artery is most often affected, and with fibromuscular dysplasia, the middle and distal segments are most often affected.
Direct signs of renal artery stenosis
The aliasing indicates the location of the turbulent high-speed flow where measurements should be made. In the area of stenosis PSV >180 cm/sec. In young people, the aorta and its branches may normally have a high PSV (>180 cm/sec), while in patients with heart failure, the PSV is low even in the area of stenosis. These features are leveled by the renal-aortic ratio RAR (PSV in the area of stenosis/PSV in the abdominal aorta). RAR for renal artery stenosis >3.5.
Indirect signs of renal artery stenosis
Direct criteria are preferable; diagnosis should not be based solely on indirect signs. In the post-stenotic region, the flow attenuates - tardus-parvus effect. In renal artery stenosis on the intrarenal arteries, PSV is too late (tardus) and too small (parvus) - AT >70 ms, PSV/AT<300 см/сек². Настораживает значительная разница между двумя почками — RI >0.05 and PI >0.12.
Table. Criteria for renal artery stenosis on ultrasound
Drawing. A 60-year-old female patient with refractory arterial hypertension. PSV on the abdominal aorta 59 cm/sec. In the proximal part of the RAA with CDK eleasing (1), PSV is significantly increased 366 cm/sec (2), RAR 6.2. In the middle segment of the PPA with CDK aliasing, PSV 193 cm/sec (3), RAR 3.2. On segmental arteries without a significant increase in acceleration time: upper - 47 ms, middle - 93 ms, lower - 33 ms. Conclusion:
Drawing. Patient with acute renal failure and refractory arterial hypertension. Ultrasound of the abdominal aorta and renal arteries is difficult due to gas in the intestines. On the segmental arteries on the left RI is about.68 (1), on the right RI is 0.52 (2), the difference is 0.16. The spectrum of the right segmental artery has a tardus-parvus shape - acceleration time is increased, PSV is low, the apex is rounded. Conclusion: Indirect signs stenosis of the right renal artery. CT angiography confirmed the diagnosis: at the mouth of the right renal artery there are atherosclerotic plaques with calcification, moderate stenosis.
Drawing. Patient with arterial hypertension. PSV in the aorta is 88.6 cm/sec (1). In the proximal part of the RPA there is aliasing, PSV 452 cm/sec, RAR 5.1 (2). In the middle section of the PPA there is aliasing, PSV 385 cm/sec, RAR 4.3 (3). In the distal RCA PSV is 83 cm/sec (4). On the intrarenal vessels tardus-parvus the effect is not determined, on the right RI is 0.62 (5), on the left RI is 0.71 (6), the difference is 0.09. Conclusion: Stenosis in the proximal part of the right renal artery.
Doppler of renal veins
The left renal vein passes between the aorta and the superior mesenteric artery. The aortomesenteric “tweezers” can compress the vein, leading to venous renal hypertension. In a standing position, the “tweezers” compress, and in a lying position, they open. With Nutcracker syndrome, outflow through the left testicular vein is difficult. This is a risk factor for the development of left-sided varicocele.
Due to compression, the spectrum of the LPV is similar to the portal vein - the spectrum is above the baseline, constant low speed, contour in smooth waves. If the ratio of the diameter of the left vein in front of and in the narrowing zone is more than 5 or the flow rate is less than 10 cm/sec, we conclude that the venous pressure in the left kidney is increased.
Task. On ultrasound, the left renal vein is dilated (13 mm), the area between the aorta and the superior mesenteric artery is narrowed (1 mm). Blood flow in the area of stenosis at high speed (320 cm/sec), reverse blood flow in the proximal segment. Conclusion: Compression of the left renal vein by aortomesenteric “tweezers” (Nutcracker syndrome).
Compression of the renal vein is possible due to its abnormal location behind the aorta. The diameter ratio and flow rate are evaluated according to the above rules.
The nature of the blood flow in the right renal vein approaches that of the caval vein. The shape of the curve changes when you hold your breath and can be flatter. Blood flow speed is 15-30 cm/sec.
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