Renal angiography is an X-ray examination of the renal arteries by administration of a radiopaque substance. It is used for the diagnosis of accessory vessels, tumors of the kidneys and retroperitoneal space, narrowing and blockages of the renal arteries; with hydronephrosis and renal hypertension. During renal angiography, a catheter is inserted through the femoral artery into the aorta to the place where the renal artery departs from it, through which contrast is injected. Then a series of X-rays are taken, which show the renal arteries filled with contrast.
Indications of renal angiography
Angiography can be prescribed for the purpose of:
- studying the vascular system of the kidneys before the upcoming operation;
- identification of the cause of renovascular hypertension;
- evaluation of the vascular system of the kidneys in chronic diseases of this organ or renal insufficiency;
- identification of tumor-like neoplasms and clarification of their type (tumors or cysts);
- control over the condition of transplanted kidneys (kidneys).
The immediate indications for angiography are:
- blood in the urine for an unknown reason;
- suspected kidney cancer;
- abnormalities of kidney development detected on ultrasound, MRI;
- tuberculosis of the kidneys;
- arterial hypertension.
On X-ray images taken with the use of a contrast agent, you can clearly see the location of the kidneys, identify their omission, anomalies of structure, damage and their nature. The main thing that can be identified is tumors and cysts, find out their size, localization, structure, density and other characteristics.
The veins and arteries of the kidneys are also well visualized. Stenoses, aneurysms, vascular malformations, blood clots are detected.
Preparation of renal angiography
Unlike simple radiography, which does not require special preparation, you need to start preparing for kidney angiography in 2 weeks, namely, completely exclude alcoholic beverages from the diet. There are other features of preparation.
- A week before the procedure, you need to stop taking medications (if such were prescribed for treatment) that dilute the blood.
- Five days before the procedure, you need to undergo the following examinations: echocardiography, ECG, fluorography, blood clotting, general, biochemical, rhesus determination, for the presence of infections (hepatitis, HIV, syphilis).
- Two days before the procedure, you need to pass a test that detects an allergy to a contrast agent (for this, a small dose of contrast will be administered to the patient).
Angiography involves a puncture of the skin. In which area it will be produced, the doctor will indicate. The patient, the day before the procedure, will have to remove the hair from this area of the skin.
- On the eve of the procedure, in the evening, you should take a sedative and an antihistamine.
- In the morning on the day of the procedure, the patient is given a cleansing enema.
- Immediately before angiography, you need to empty the bladder.
- On the day of the procedure, you can’t eat or drink anything in the morning.
Methodology of conducting
There are several techniques for doing kidney angiography.
For such a diagnosis, a contrast agent is injected into the femoral artery. For the study, it is necessary that:
- the patient lay on his back;
- the injected anesthesia took effect.
Next, a puncture of the skin is performed, a catheter is inserted and contrast is supplied to the vessels. In the first minutes of its spread, an arteriogram and a nephrogram are performed. At the end of the procedure, a venogram is made. Five minutes after the first X-ray, an excretory urogram is performed.
This method differs from the previous one in that the puncture is performed in the lumbar region.
The patient lies down on his stomach, stretches his left arm along the body, and his right arm to the side (to register pressure and pulse). After the beginning of the anesthesia, a puncture is performed and a contrast agent is injected. Further, the images are performed in the same way as with transfemoral aortography.
Dynamic indirect kidney angiography is a rather complicated procedure that cannot be prescribed in the presence of the following contraindications:
- pregnancy (all trimesters);
- tuberculosis of the lungs;
- poor blood clotting;
- atherosclerosis of blood vessels;
- renal, pulmonary, and hepatic insufficiency;
- allergy to iodine;
- serious condition of the patient (caused, in particular, by cancer);
- arrhythmia, angina pectoris and other pathologies of the cardiovascular system in severe form.
When deciphering the results of angiography images, it is important to consider the following:
- How clearly the vessels are visible, their contours, whether there is an interruption of the image.
- Are there any blackouts. If there are, then what size are they, where are they localized, how dense are they.
- The nature of the distribution of the substance for contrast: whether it enters the capillary system or immediately rushes into a vein, whether it enters soft tissues or remains in the vascular system.
A correct conclusion based on angiography can be made only if the contrast agent was injected evenly and distributed throughout all the vessels, aorta and arteries of the kidneys. An isolated examination of certain vessels and channels is carried out only if the condition of the other kidney is reliably known, based on a set of other studies.