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One of the most popular and most informative methods of X-ray examination of the kidneys is pyelography, which is performed by introducing a liquid radiopaque substance into the pyelocaliceal cavity of the kidneys. Almost always, this examination is accompanied by urography – X-ray diagnostics of the ureters. Both procedures are aimed at identifying various kinds of pathologies, changes in the appearance and shape of the renal pelvis itself, as well as its contour, calyces and renal papillae.
Types of pyelography
When diagnosing the renal apparatus, an image of the ureters is also often required, so pyelography is performed simultaneously with urography. One of the varieties of this procedure is pneumopyelography, when oxygen or carbon dioxide is used for diagnosis. This technique allows you to diagnose the presence of bleeding or calculi in the kidneys, as well as to identify tumors or kidney tuberculosis.
Sometimes the method of double contrasting is used, when both liquid contrast agent and gas are used in pyelography at the same time.
Depending on the method of administration of the radiopaque substance, pyelography is divided into several types: retrograde or ascending, intravenous or excretory, as well as antegrade or percutaneous pyelography.
This study can also be used in combination with surgery. Such pyelography is called intraoperative. There are some contraindications for carrying out such a technique, depending mainly on the method of introducing a contrast agent into the body. But for all variants and types of pyelography, a common contraindication is hypersensitivity or individual intolerance to iodine or other components of the radiopaque substance.
The most commonly used contrast agents are: trazograph, iohexol, iopromide, sodium iopodate, sodium amidotrizoate, novatrizoate, and iodamide.
If the degree of tolerance of a particular drug is unknown, then the contrast agent is injected in a test mode, with a volume not exceeding one milliliter. In case of hypersensitivity, the patient may experience adverse reactions in the form of nausea, dizziness and a feeling of heat.
Indications and contraindications for examination
Pyelography is often prescribed in order to identify the presence of various pathologies in the human body:
- blockage of the ureters by blood clots or stones;
- hydronephrosis;
- various renal injuries;
- expansion of the renal pelvis;
- narrowing of the ureters;
- tumors in the cavity of the renal pelvis, calyces and ureters.
Also, this procedure is used as an additional procedure when placing a catheter or ureteral stent.
However, there are a number of contraindications for this study. But it is worth noting that the existence of several varieties of this procedure allows you to bypass a number of contraindications and conduct an examination in almost every patient. To do this, it is only necessary to find the most acceptable method of introducing a radiopaque substance. General contraindications for all types of pyelography are:
- hypersensitivity to preparations containing iodine;
- period of pregnancy;
- vascular and heart diseases;
- chronic and acute form of renal failure;
- blood poisoning;
- severe hypertension;
- thyroid pathology: thyrotoxicosis and hypothyroidism;
- bleeding disorders;
- infectious and inflammatory processes in the lower urinary tract.
Types of pyelography, preparation and execution of the procedure
Each separate type of such research has its own characteristics, advantages and disadvantages. The method by which a contrast agent will be introduced into the patient’s body is determined by the attending physician based on the individual characteristics of the patient and the alleged disease.
Pyelography is:
- retrograde;
- antegrade;
- intravenous.
Retrograde pyelography is a type of procedure in which a contrast agent is injected into the patient’s body through the urethra using a catheterized long cytoscope. In this case, such medications as urographin, triombrast, verografin, iodamide are used.
The same drugs are often used for intravenous pyelography. However, specifically in this case, they are used in a glucose solution and in high concentrations.
Because of this, the image with retrograde pyelography is very contrasting, which makes it possible to detect even the slightest changes in the renal pelvis pattern.
A few days before the retrograde pyelography, it is recommended to exclude foods that cause increased gas formation from the diet. And just before the procedure itself, perform a cleansing enema. Pyelography is usually performed in the morning, so breakfast should be canceled and fluid intake should be limited.
The procedure consists in the fact that a radiopaque substance is injected into the cavity of the renal pelvis under pressure. The pelvis reaches volumes of five to six milliliters, so the substance should also be administered in small volumes, since distension of the pelvis can lead to an acute attack of renal colic.
Pain in the lumbar region during or after the procedure indicates a possible complication – pelvic-renal reflux. Usually, retrograde pyelography is performed in several positions: standing, as well as lying on the stomach, side or back.
Antegrade pyelography is used when it is not possible to perform a retrograde injection of a contrast agent. This type of procedure is performed by introducing a radiopaque preparation into the renal pelvis using a percutaneous puncture or nephrostomy drainage.
This procedure differs from retrograde pyelography in more thorough preparation. And after the examination, antibiotic therapy or the installation of a nephrostomy tube is often required. It is also recommended to completely refuse food and fluid intake six to eight hours before the start of the study and to do a cleansing enema on the eve of the study.
In antegrade pyelography, the patient is placed in the prone position. First, a primary survey radiography of the renal region is made, on the basis of which a long needle is inserted into the cavity of the pelvis. The procedure is accompanied by the introduction of anesthesia.
Some of the urine is diverted, and a contrast agent is injected and pyelography is performed. At the end of the procedure, the contents of the renal pelvis are removed and an antibacterial drug is injected using a syringe. Blood clotting disorders are a direct contraindication for antegrade pyelography.
Intravenous or excretory pyelography allows you to conduct an examination for quite a long time. In this type of radiography, a dye is injected into the systemic circulation through a vein. This method of examination contributes to a good view of all departments and areas of the urinary system.
Intravenous pyelography is used if for some reason it is impossible to carry out a retrograde or antegrade procedure.
Preparation for such an examination is required even more thorough, especially in cases where the patient is allergic to iodine-containing drugs. Before carrying out the procedure in such patients, it is necessary to introduce the necessary dose of prednisolone into the body in order to exclude the possibility of anaphylactic shock. In addition, you must follow an appropriate diet, as with other types of procedures, conduct a cleansing enema and refrain from eating and drinking before the procedure.
The contrast agent is administered intravenously, in a dosage proportional to the patient’s body weight, but not less than forty milliliters for adults. The procedure usually takes about half an hour. If pharmacourography is also required, an isotonic solution of furosemide should also be administered.
Such an examination is carried out in a standing and lying position, which allows you to consider pathological changes from different angles. Before the main dose of the radiopaque substance is administered, a sensitivity test is performed by injecting a very small dose intravenously, approximately one millimeter of the drug. If after five minutes the patient does not show any allergic reactions, then a complete examination is already carried out.
Summing up
Pyelography is one of the types of radiographic examination, which allows you to identify the presence of various kinds of pathologies in the urinary system. It is carried out in various ways, depending on the input of a contrast agent into the human body. There are a number of contraindications to conducting such a study, therefore, before it, it is necessary to consult a doctor and take some tests in order to exclude possible negative consequences.