Intravenous urography is a method of X-ray diagnostics that displays the kidneys, renal pelvis, bladder, ureters and urethra. The study is applicable in the diagnosis of tumors, urolithiasis, inflammatory changes and congenital defects of the structure of the urinary organs. Intravenous contrast is preferred. In a two-phase study, images are taken with and without ureteral compression. The cost increases when the price of the contrast agent is taken into account.
Intravenous urography is used to diagnose a number of kidney and urinary tract lesions, which can manifest a wide variety of symptoms. The most common indication for this diagnostic study is renal colic (cupped forms) caused by urolithiasis. Unlike ultrasound, which simply detects the presence of concretions in the pelvis or ureters, intravenous urography also shows how much the functional activity of the kidneys has suffered. The procedure is used for lower back pain associated with kidney disease, hematuria (the presence of blood in the urine) unknown origin, suspected tumor processes in the urinary system. Along with ultrasound, intravenous urography is prescribed for polycystic kidney abnormalities, nephroptosis, chronic pyelonephritis and suspected renal failure.
Absolute contraindications are mostly associated with the use of iodine-containing contrast agents. These include severe renal insufficiency, including acute, bronchial asthma, the presence of diseases of the endocrine system (diabetes mellitus, hyperthyroidism), hypersensitivity to radiopaque substances. The list of absolute contraindications to intravenous urography also includes pregnancy – due to the use of contrast agents and X-ray irradiation. Relative contraindications are arterial hypertension, non-reversible forms of renal colic, increased pressure in the portal vein system (portal hypertension).
If the procedure is performed as planned, then it is necessary to prepare for the study in order to obtain more accurate results. 1-2 days before the manipulation, it is recommended to exclude from the diet foods that enhance the processes of gas formation in the large intestine – some vegetables (cabbage, potatoes), black bread, fresh fruits and sweet dishes. On the eve of intravenous urography, it is advisable to make a cleansing enema, dinner should consist of light meals and be no later than 18 hours. In the morning on the day of manipulation, you should refrain from breakfast, in some cases, a repeated cleansing enema is prescribed. However, all these recommendations are not strict, if there is a need for urgent research, they can be abandoned.
Methodology of conducting
To perform a diagnostic procedure, a conventional X-ray machine is sufficient, but in a number of medical clinics special X-ray telescopes with the possibility of video recording of the process are used for this purpose. This is the preferred option, as it allows you to record the entire process of intravenous urography and significantly reduces the risk of missing any violation or anomaly. Immediately before the examination, the patient empties the bladder, the nurse injects a contrast agent into his ulnar vein – usually a jet injection of 40-60 ml of solution is practiced for 2-3 minutes. The exact amount of contrast is calculated by the doctor depending on the patient’s weight. If it is not possible to make video recording of intravenous urography, consecutive pictures of the abdominal area are taken at certain intervals. The first picture is taken 1-2 minutes after the drug administration, the second – after 6-7 minutes, the third – after 15-20 minutes.
With reduced functional activity of the kidneys, it is possible to take subsequent images 40 minutes after the introduction of a contrast agent, if necessary, X-rays are repeated after 1-2 hours. If it is known that the patient has a reduced activity of the urinary system, it is recommended to slightly modify the process of intravenous urography. To do this, the contrast agent is not injected in a jet, but dissolved in a 5% glucose solution and a dropper is installed, which ensures a slow uniform flow of contrast into the blood. After completion of urography, if there are indications, a study of the bladder (cystography) and urethra (urethrography) can be performed.
Interpretation of results
When evaluating the results of intravenous urography, the radiologist takes into account a number of indicators – the rate of contrast from the blood to the kidneys, the shape and size of the cup-pelvis complex, the presence or absence of filling defects in the kidneys and ureters, and a number of others. With reduced functional activity of the urinary system, the time of contrast entering the urine increases, which is manifested by the absence of signs of the nephrographic phase (accumulation of contrast agent in the kidney tissues) 1-2 minutes after administration.
A significant expansion of the CPS indicates an increase in pressure in the urinary system and indirectly indicates the presence of stenoses, stones, tumors or other obstacles to the outflow of urine. The latter can be visualized as filling defects in the pelvis or ureters – it is on this basis that tumors and X-ray negative stones can be detected. The most reliable results are obtained by intravenous urography with X-ray video recording of the contrast extraction process.