A kidney x-ray with contrast medium (contrast): preparation, testimony
To assess the condition of the urinary system by using different methods: radiography (including contrast), ultrasound, CT, MRI, scintigraphy. X-ray examination of the kidneys is a common and highly informative method of diagnostics of diseases of organs responsible for the excretion of urine. However, only at the possibilities of the method are not limited. X-ray of kidney allows to assess the functional state of the organ under investigation.
Of course, this diagnostic method is not without flaws. First, it is based on the use of ionizing radiation. Secondly, the study is conducted with the use of radiopaque drugs with side effects. The latter range from benign, self-stoped disorders (nausea, metallic taste in the mouth) to severe complications (anaphylactic shock). However, if safety precautions the risk of adverse consequences can be minimized.
A contrast agent that allows to expand the diagnostic capabilities of x-ray research method — iodine-containing water-soluble drug that are excreted from the organism with urine in an unmodified form (urografin, urotrast). To introduce it into the blood stream (this method of research is called excretory urography) in two ways:
- Intravenous drip.
The latter method (intravenous urography) at the expense of slower and more prolonged injection of contrast helps to better visualize the parenchymal tissue of the kidneys, as well as the calyx and pelvis. Such a study informative even with reduced function of the investigated organ. To perform urography in children under one year drip is preferable. In a jet flow of contrast images of the kidneys obtained is not clear because of the «immaturity» of the nephron.
Opacification of the urinary tract occurs not only through intravenous drug. Other options urography include:
- Retrograde. Cup-pelvis-plating system is filled with contrast through a catheter inserted in the ureter. The need to study arises, if excretory urography does not provide a clear image of the urinary tract. However, the capabilities of the method are limited. The introduction of the catheter may be difficult or impossible with ureteral obstruction by stone or squeezing it from the outside, for example, tumor.
- Antegrade. Contrast is injected through nephrostomy (drainage tube installed in the renal pelvis), or when performing a percutaneous puncture of the Cup-pelvis-plating system. This study applies if excretory urography uninformative, to introduce a contrast retrograde does not work.
You can visualize the vessels. To do this, in the renal arteries the injection of contrast medium. The series of images allows us to consider the vessels of different caliber. In the beginning of the study are visualized main artery, then smaller. Finally, the contrast flows into the Cup-pelvis-plating system, allowing you to see the urinary tract. This method (angiography) is indicated in cases of suspected pathology of the vascular system of the kidney (occlusion, anomalies of development), as well as the performance of endovascular procedures (stenting, embolization).
X-ray with contrast is not limited only to research of the kidneys. This method is effective and for the assessment of lower urinary tract: bladder (cystography), the urethra (urethrography).
When assigned to the study?
A kidney x-ray contrast agent, has extensive diagnostic capabilities. Of the above methods is most often used excretory urography. Compared with retrograde or antegrade nor does it involve invasive procedures: insertion of a catheter, the puncture.
When you do a kidney x-ray with contrast:
- Blood in the urine (gross hematuria).
- Changes in the urine, persisting for more than 2 months.
- Suspected renal hypertension (a variant of arterial hypertension, the cause of which is renal pathology).
- Trauma of the abdomen and the lumbar region.
- Detection on the overview picture of the pathological changes of the organs of the urinary system.
- Pain in the lower back and abdomen.
Contrast study, therefore, is used to detect abnormalities of the structure, diseases and injuries of the kidneys, as well as their functions. If you need more information, there are other methods: angiography, CT, MRI.
Who can not do x-rays?
Radiography with contrast is a more hazardous procedure than performing the review snapshot. This is due to a combination of adverse effects of ionizing radiation and of the drug. By itself, x-rays can not be done only during pregnancy. The use of contrast expands the list of contraindications. They added:
- Intolerance to iodine.
- Receiving glucophage drug for the treatment of diabetes. Its joint use with contrast agent can cause acute renal failure.
- The decline in renal function: acute and chronic renal failure.
- Diseases affecting the functionality of the kidney (e.g., pheochromocytoma).
With caution to study patients with allergies and bronchial asthma patients. The risk of allergic reaction to the drug is much higher.
Side effects of contrast
Despite the safety of modern agents used for x-ray examination of the kidneys, to exclude completely the risk of adverse events impossible. The introduction of the drug may cause the following reactions:
- The feeling of heat and a metallic taste in the mouth – most common side effects usually go away by themselves, do not require assistance.
- Nausea, vomiting.
- Rash, pruritus.
- Pain, burning, numbness at the injection site. Reaction is associated with the contact vein into the surrounding soft tissue.
- Anaphylactic shock.
The last complication can lead to death of the patient if assistance is provided late or incorrectly. For this reason the patient can’t be left alone after injection of contrast agents. A set of tools to assist in the development of such complications, should be at hand.
How to prepare for the exam?
Preparation for x-ray of the kidneys includes activities aimed at reducing the intestinal gas formation. Pronounced flatulence reduces the informativeness of the study. To avoid this, you must:
- 2-3 days before the procedure to limit the consumption of foods that stimulate flatulence (pastry, apples, brown bread).
- Stop eating 8 hours before the study.
- To release the intestines, it is desirable to do two cleansing enemas – the previous evening and in the morning.
- Immediately before the procedure you should empty your bladder. This condition is especially important in the study of the lower urinary tract, since mixing of the contrast with urine will lead to its dilution and loss of information content of the image.
Preparing the patient for x-ray study of the kidneys also includes the discontinuation of glucophage for 2 days before procedure. It is mandatory to clarify the indicators of creatinine and urea. Insufficiency of the kidney – contraindication to taking pictures.
How is the study?
The first x-ray of the kidney – an overview, without the use of contrast. The purpose described above. After the execution of the injected contrast. The average volume for an adult is 40-50 ml. in the study of the kidneys in children using different methods of dose calculation. The most accurate method is the determination of the dose depending on the body surface of the child:
- 2-4 years (0,6-0,9 m2) 15-23 ml
- 5-8 years of (0.7-1.1 m2) – 18-28 ml
- 9-12 years (0.8 to 1.4 m2) – 20-35 ml
- 13-15 years (1.1 to 1.8 m2) – 28-45 ml
How do x-rays? All photos are taken with the breath on the exhale after a certain period of time:
- Immediately after injection of contrast is made programme. The drug in this phase accumulates in the nephrons, allowing you to see on the x-ray the renal parenchyma. The patient lies on his back, arms along the body. The x-ray beam is aimed at the mid-point between xiphoid process and iliac crest.
- After about 5 minutes. In this picture clearly visible to the entire urinary system. The most convenient projection – rear, lying on his back. The center of the cassette is at the level of the crests of the iliac bones.
- In about 15 minutes. Is also performed in rear projection lying on the back.
- In about 20 minutes. Pictures are made in the oblique projections (left and right). The patient lies on one side (left or right), body turned to the table surface at an angle of 30°, arms raised to the head, upper leg bent at the knee.
- In case of delay in contrast to make an extra (delayed) images of 45 and 60 minutes.
In the rear projection standing is done if you suspect nephroptosis (omission kidneys). A modification of the rear styling is the position of the patient in the Trendelenburg position with a raised foot end of the table. This position allows you to hold the contrast in the upper third of the urinary tract and to conduct advanced diagnostic search pathology of this region.
Radiation exposure when the picture was taken of the kidneys is 0.1 and 0.6 mSv for digital and film apparatus respectively. Fluoroscopy is currently not considered feasible because of the large doses of radiation. The implementation of a series of images instead of lengthy monitor progress of the contrast in real-time significantly reduces the harmful effects of radiation on the patient.
As seen in the picture?
Excretory urography can detect the following pathologies:
- Anomaly of development: doubling of a kidney (double Cup-pelvis-plating system in the picture), a doubling of the ureter, dystopia (abnormal location of the kidney).
- Nephroptosis. Dystopia is different from the normal length of the ureter, severe removability of the kidney when changing posture, the discharge of the renal artery from the aorta at the usual place.
- A renal cyst. On the x-ray is visible as a local bulging of the. When multiple cysts of the kidney increased in size, has a wavy contour.
- Tumor. The kidney is enlarged, deformed, contour uneven.
- TB. Cavities are visible as local vbuhanie, in the parenchyma there are areas of calcification.
- Hydronephrosis. The kidney is increased due to the expansion of the Cup-pelvis-plating system, can be observed waviness of the outline.
- Urolithiasis. Radiopaque stones are visible in the overview picture. The introduction of the drug allows to detect signs of impaired patency of the urinary tract: the expansion of the cups and pelvis, delayed contrast.
When the kidney injury of the ability of x-rays is limited. CT and ultrasound are much more informative, especially in the diagnosis of hematomas. Excretory urography visualizes injuries involving rupture of the kidney. The photos show streaks of contrast material in the parenchyma of the organ and surrounding tissues.
Alternative methods of kidney
CT allows you to see buds without even doing contrast, it is clearly visualized and adjacent organs. Tomography makes it possible to consider the renal parenchyma and not only the urinary tract. When excretory urography this can only be done at the earliest photographs – programmah. The introduction of a contrast agent when performing a CT scan increases the diagnostic capabilities of the method. Such images help to differentiate cortical and medullary substance of the parenchyma and review of the renal vessels. MRI also allows you to see buds without the use of contrast. The latter is introduced for more detailed information.
The possibility of taking pictures without contrast enhancement allows the use of CT and MRI in patients with impaired renal function. These methods are indispensable in the diagnosis of cancer. They can be used to explore not only the condition of the kidneys, but also the neighboring organs, to determine the prevalence of cancer.
Ultrasound is a good alternative to radiological methods, because it does not expose the patient to risk of radiation, and no side effects of the administered contrast agent. Mode Doppler ultrasound can be considered vessels and to assess renal blood flow. Of course, the image quality of ultrasound is inferior to CT and MRI.
Radionuclide method based on the detection of radiation in the kidneys after the introduction of nephrotropic radiopharmaceutical. Research is used primarily to evaluate kidney function (dynamic scintigraphy). However, it is possible to investigate renal blood flow (angioprotektivnoe) and the anatomy of the body (static scintigraphy).