Dopplerography of the kidney: technique, results, indications
In the diagnosis of pathologies of the urinary system, the so-called indirect methods play an important role. So doplerografiya kidneys can give an idea of the work of nephrons, to explore which "in vivo"( in a living organism) at the moment is not possible.
The essence of the method of dopplerography
This method of research has two more complete names. This is ultrasound of the kidneys with dopplerography and ultrasound - ultrasound dopplerography. This gives a more or less complete description of the essence of the method. It is an improvement of ultrasound.
The usual method of ultrasound is based on reading reflected sound waves, whose frequency exceeds 20 thousand hertz. The denser the tissue, the more intense the reflection of the waves. Reflected waves are captured by a special sensor. And the information coming from him is displayed on the screen. Here she is seen by an expert in ultrasound diagnostics, and he also draws conclusions.
This is important! UZDG uses reflection waves from moving objects. As a result, the apparatus forms a graph of the fluid motion. In the case of blood vessels, blood cells are used.
Results of the
study This is important! A computer-generated graph carries information on the main parameters of blood flow. This is the speed of motion, linearity of motion, as well as the flux density.
The obtained data are used for two main conclusions:
- Penetration of renal vessels. Namely - the renal vein and the renal artery.
- Blood flow in nephrons.
The last parameter is conditional, since it gives approximate results. It is based on data from the study of the main vessels of the kidney. Only they are accessible to direct research. The fact is that only about 95% of the blood entering the kidneys passes through the nephrons. The rest of the blood goes through arteriovenous anastomoses.
The permeability of the renal vessel is determined by direct ultrasound scanning. The doctor on the monitor of the device can see the state of the vessel quite well. Namely, its diameter and the state of the wall. If there is any constriction( stenosis, atherosclerotic plaque), it is immediately fixed on the monitor.
The idea of the blood flow clearly shows the graph obtained by the above-described Doppler effect. Moreover, the picture of the vessel and the graph are parallel. Their complete correspondence in the coordinate system gives a complete picture of what is happening in the vessel.
And as for the blood flow in the kidney, it can be judged from the analysis of blood flow along the artery and vein. Excess of the speed of arterial and venous blood flow, most likely, speaks in favor of the fact that more than 5% of the blood goes through the anastomoses. Slowing down the blood flow can be inferred in the opposite direction, but with some conventionality. Often there is a situation that the blood can not go on anastomoses in the consequence of their defeat.
Preparation and procedure of
Doppler examination of renal vessels requires the same preparation as simple ultrasound examination of the urinary system:
- 2-3 days before the study, it is recommended to avoid products that cause increased gas production in the intestine. These are all raw vegetables and fruits, confectionery, gray bread, beans, legumes, carbonated drinks. The use of sorbents( activated charcoal, semiticon) is recommended only on indications. That is, for people suffering from diseases of the intestine and other digestive organs with a tendency to gassing.
- For 5-6 hours complete abstinence from food. Use water moderately. This is especially true for those who can have an additional study of the bladder. Therefore, the study is ideally conducted in the morning.
The study is conducted more often in the supine position on the side. This maximizes the distance between the kidney and the sensor. Directly before the procedure, a special gel is applied to the sensor( or skin).This is necessary for better passage of ultrasonic waves: the gel makes it easier for them to pass through the layers of the skin.
Advantages of ultrasound using Doppler ultrasound technology are obvious. The method does not carry any radiation load. The research is conducted in the present tense and all the results are comparable with it. With the help of this method, it is possible to study rather well the state of soft tissues, which are not visible on the x-ray at all. Finally UZDG is a fairly inexpensive method, it is so widely available and does not require expensive consumables.
However, in some pathologies USDG and simple ultrasound are not informative. This primarily concerns the calcification of the vessel wall. In this case, ultrasonic waves simply can not penetrate further through the wall. The method is not recommended for the detection of pathologies of small vessels.
Indications for the
study The appointment of a Doppler ultrasound is indicated in the following cases:
- Suspected circulatory disorders in the kidney vessels. Most often this situation occurs when:
- Atherosclerosis.
- Ascending thrombophlebitis of the inferior vena cava.
- Vascular compression of the tumor.
- Nephroptosis of the last stage.
- Abnormalities of blood vessels.
- Study of blood flow in arterial hypertension. In this case dopplerography of the kidney is done to exclude renal causes of increased blood pressure.
- Control of the effectiveness of treatment of all the above pathologies.