Ultrasound is one of the most informative and at the same time safe methods of examination, allowing to assess the condition of internal organs. Over time, research technology was enriched with new techniques, which markedly expanded the scope of application. Ultrasound dopplerography of the kidneys and blood vessels is one of these new methods.
Ultrasonography of kidneys and kidney vessels with dopplerography
It's no secret that the functionality of many organs can be assessed not so much on the condition of the tissue, but as the condition of the serving arteries and veins. This is quite natural: after all, food and oxygen are received from the body or tissue only with blood. The task of examining the vessels and solving dopplerography.
This method involves ultrasound based on the Doppler effect. Its essence is as follows: the surveyed area is irradiated with ultrasonic waves. When a motionless reflecting body is detected, the reflected wave-the echo signal-has the same frequency as the ori
ginal one. When meeting moving objects, the frequency of the reflected wave changes: it becomes larger if the moving body moves towards the sensor or less, if it moves away from it. This change between the indices of the initial ultrasonic pulse and the reflected signal is called the Doppler shift.
There is a spectral and visualization ultrasound of dopplerography.
- Spectral - during the examination the intensity, frequency of the echo signal is fixed, and according to these data a curve is drawn. It gives an idea of the distribution of speed in the blood flow and the direction of movement in the vessel.
- Visualization - the same data is interpreted as a visual representation of blood flow parameters. This method is more obvious and allows us to study the state of several organs and vessels. There are duplex dopplerography - a two-dimensional image in black and white, and color - with color Doppler mapping.
The function of the kidney depends on the state of the blood flow. And even in those cases when the kidney tissue itself is not damaged. US dopplerography of the kidneys and blood vessels makes it possible to determine the following factors:
- level of damage to the walls of blood vessels and arteries in thromboses, atherosclerosis and other;
- presence of thrombi or atherosclerotic plaques;
- blood circulation parameters: blood volume, flow rate, velocity distribution;
- the size of the vessels, which allows us to identify stenosis, segmental stenosis, spasm;
- dimensions of the organ, shape, homogeneity or heterogeneity of the structure;
- structure of the parenchyma;
- violation and the cause of microcirculation disorders.
As for the condition of the vessels and their working capacity, it is possible to assess not only the current state of the organ, but also the effectiveness of the treatment, so ultrasound dopplerography is performed not only in diagnosis but also during treatment.
The reason for the appointment of Doppler examination is both established pathology, and certain symptoms that indicate a particular diagnosis. These include:
- pain and discomfort in the lumbar region, which are permanent;
- renal colic of any severity;
- swelling of the limbs, face;
- blood, protein, an increase in the number of white blood cells in the urine;
- disorders of cardiovascular activity, especially against the background of increased diastolic pressure;
- contusions and injuries in the lumbar region, since they are fraught with damage to blood vessels;
- hypertension of any origin;
- acute and chronic forms of renal ailments or genitourinary system - in the latter case, a bladder examination is usually prescribed;
- endocrine disorders - vasculitis, diabetes mellitus;
- late toxicosis in pregnancy;
- suspected tumor;
- Vessel Diagnostics - to determine congenital and acquired anomalies;
- assessment of vascular and organ status after kidney or other organ transplantation.
There are no contraindications for the survey. However, one must take into account that the state of small vessels in this way is difficult to assess.
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procedure Dopplerography requires preparation. The fact is that the state of the intestine, and, more precisely, the presence of gases here, greatly hampers research.
In fact, the whole preparation is to exclude or minimize this phenomenon:
- 2-3 days before the examination, the patient must follow a diet that excludes all products that cause increased gas production. This cabbage in all forms, bakery products - allowed white crackers, legumes, raw vegetables and fruits, sweets, especially chocolate, coffee and carbonated drinks. As a rule, milk and dairy products are excluded, since quite a few people do not absorb this product very well.
- To reduce gas generation, especially with a tendency to do this, use activated charcoal, sorbet, espumizan - 2 tablets 1-3 times a day, depending on the condition and well-being.
- The procedure is performed on an empty stomach: drinking and eating for 8-12 hours before the examination is prohibited, therefore the examination is almost always carried out in the morning. If the procedure is scheduled for the afternoon, a light breakfast is allowed, however no later than 6 hours before the ultrasound.
- It is also not possible to take medicines before the examination. An exception is made for patients whose treatment requires constant intake of drugs: diabetes, arterial hypertension, ischemic heart disease, and so on.
The procedure for performing the
The procedure itself does not present any complications:
- The patient undresses to the waist, removes jewelry if there is one in the area under investigation and is placed on the couch sideways.
- The doctor applies a special gel to the sensor, which provides the most dense contact between the skin and the sensor.
- The specialist moves the sensor over the site in the projection of the location of the kidneys. The device emits ultrasonic waves of a certain length. The signal, when encountered with a mobile obstacle - red blood cells, is reflected with a different frequency. The reflected wave is picked up by the sensor and converted into electrical pulses.
The latter are converted by the device itself and rendered graphically or as a color image. The image is dynamic, which allows you to assess the movement of blood on the vessels in real time and record any deviations from the norm.
For example, the rate of circulation in the main renal arteries ranges from 50-150 cm / s. With stenosis, when the working bed is reduced by 70-80%, the blood flow rate increases markedly, and then falls sharply. In the image, the accelerated circulation is colored with a brighter color, while the slower one is pale. In addition, the device captures and displays turbulence in the artery.
During the procedure, a two-dimensional image of the studied area is created on the screen. The doctor fixes the necessary parameters for the image. The data is reflected in the document to be filled out.
The whole procedure takes no more than 30 minutes and is completely painless.
On video, performing dopplerography of renal vessels:
The result of ultrasound is a study protocol that includes all the parameters necessary for assessing the condition:
- form - normally the kidney should have a bean-shaped form;
- the contour of the organ should be clear and even;
- the sizes of kidneys should coincide, the difference is allowed not more than 2 cm;
- capsule structure is hyperechoic, that is, strongly reflects ultrasonic waves, capsule thickness up to 1.5 mm;
- echoplotnost renal sinus and peroneal tissue should be equal;
- echomodality of pyramids is lower in norm than in parenchyma;
- the right kidney should be slightly lower than the left;
- with respiration, the kidney is displaced by 2-3 cm, no more;
- anteroposterior size - up to 15 mm;
- primary artery resistance index - the difference between systolic and diastolic velocity in relation to the maximum systolic blood flow velocity, should normally be: 0.36-0.74 in the interlobar arteries and 0.7 in the gate region;
- anatomical location of arteries and veins;
- condition of the vascular wall - normal thickening, tears, aneurysms, thinning should be absent;
- the lumen of the vessel - for the main trunk, for example, the norm is 3.3-3.6 mm, for the interlobar artery - 1.4-1.6 mm, for the segmental artery - 1.9-2.3 mm, and so on.5 renal arteries are necessarily examined;
- assessment of the condition of the adrenal and perineal tissues;
- resistance index - measured at 3 points: in the final, middle and proximal part of the arterial vessel. The significant difference between the data in the kidneys indicates a violation of blood circulation.
The ultrasound of doppler ultrasound can not be considered absolute. The method allows you to assess the state of up to 90% of the kidney vessels, but not everything can fix. But in this case, too, ultrasound is considered to be the most informative and important methods of diagnosis from the existing ones.