Intravenous urography (also known as intravenous pyelography) is an x-ray procedure which is used to assess problems in the kidneys, ureters, bladder, and urethra. These structures make up the urinary tract. The urinary tract does not show up well on ordinary x-ray pictures. However, with intravenous urography a contrast dye is injected into the vein (intravenous injection). The dye travels in the bloodstream, concentrates in the kidney, and is passed out into ureters with urine made by the kidney. The dye blocks x-ray so the structure of the kidney, ureters and bladder shows up clearly as white on x-ray picture.
An intravenous urography is a test that allows your doctor to look at your urinary to look at your urinary system, using a special dye (contrast medium) that shows up on x-ray. The dye is injected into one of your veins and travels through your bloodstream, before being removed by your kidneys and passing into your ureters and bladder. The dye helps to show up these organs more clearly on x-rays. The test can help find out the cause of urinary problems. It may help diagnose kidney and bladder stones, tumours, blood clots, an enlarged postdate gland or narrowing in the ureters. It’s routinely done as an out-patient procedure in a hospital radiology department.
Indications
Suspected urinary tract pathology
Repeated infections? Focus, damage, (when liked with other symptoms.)
Heamaturia
Investigation of hypertension not controlled by medication in young adults.
Renal colic.
Trauma.
Contra indications:
General contra indications to water-soluble contrast agents.
Hepato renal syndrome,
Thyrotoxicosis,
Pregnancy, (allow 28 days from childbirth)
Blood urea raised above 12 mmol/L urogarphy unlikely to be successful.
Intravenous urography used for?
Intravenous urography can help to assess range of problem. For example:
Kidney stones. A stone in a kidney or ureter will normally show up quite clearly.
Urine infections. If you have recurring infections of the bladder or kidney, an IVU may help to find if you have a blockage or other abnormality of the urinary cause.
Obstruction or damage to any part of the urinary tract can often be seen on an IVU.
Alternatives to an intravenous urography
Depending on your medical condition, your doctor may suggest an alternative imaging test, such as plain x-ray of your urinary system, an ultrasound or a CT (computerized tomography) scan. You may offer a more direct test called a cystoscopy.
Preparing for intravenous urography
You may ask not to drink for a few hours before having a urogram. You may also be asked to take laxative to make sure your bowel is clear of faeces. The hospital will give you detailed advice beforehand. If you normally take medicines (e.g. tablets for high blood pressure), continue to take these as usual, unless your doctor specifically tells you not to. If you’re unsure about taking your medicines, contact your hospital.
At the hospital, a radiographer (a health professional trained to perform imaging procedures) will operate the x-ray machine and produce images on film or in digital format. You should tell your radiographer if you’re pregnant or if you might be pregnant. An intravenous urography isn’t recommended for pregnant women, unless there is an urgent medical reason. You will be asked to sign a consent form. This confirms that you understand the risks, benefits and possible alternatives to the procedure and have given your permission for it to go ached.
Film sequence:
Preliminary film, (35×43 cm) supine full A.P. abdomen to include lower border of symphysis pubis and diaphragm, to check abdominal preparation, exposure values and for any calcifications overlying the renal tract areas.
Supplementary films to determine position of any opacities. 35o posterior oblique of the renal areas. Tomogram of the renal areas at 8-11 cm.
Immediate film, (24x30cm) A.P. of the renal areas to show the nephrogarm, i.e. the renal parenchyma opacified by the contrast medium in the renal tubules.
5 minute film, (24×30 cm) A.P. of the renal areas to determine if exaction is symmetrical or if uptake is poor and a further dose of contrast agent is required. Compression may be applied in some centres at this point to distend the pelvicalceal systems to demonstrate any filing defects and a film taken at 10 minutes of the renal areas. Compression should not be used in cases of suspected renal colic, renal trauma or after recent abdominal surgery.
15 minute film (35×43 cm) (on release if compression has been applied) to demonstraste the pelvicalyceal systems and the ureters.
25 minute film (24×30 cm) 15o caudal angulations centred 5 cm above the upper border of the symphysis pubis to demonstrate the distended bladder.
Post Micturition film (24×30 cm) 15o caudal angulations centred 5 cm above the upper border of the symphysis pubis to demonstrate the bladder empthing success, and the return of the previously distended lower ends of ureters to normal.
Preparation do I need to do before intravenous urography
Basic abdominal preparation, aperients taken for 24 hours previous, to clear faecal residue.
Nil by mouth for 4-6 hours before the examination.
Patient to remain ambulant as long as possible to reduce air swallowing.
Your kidneys have to be able to filter the dye. Therefore, it is seldom performed if you have kidney failure. Before the procedure you may need a blood test to check that you do not have kidney failure.
Tell your doctor if you have any allergies, especially allergy to contrast dyes such as iodine.
You may be asked not to eat for several hours before the procedure. This ensures that your intestines are empty of food which makes the x-ray picture clearer.
You may give some laxatives to take for a day or so before the procedure. The aim of this is to clear the intestines, which will make the x-ray pictures clearer.
You may be asked to sign consent from to confirm that you understand the procedure.
If you have diabetes and take metformin you may need to stop the metformin for two days prior to the procedure. This is because the combination of metformin and contrast dye may affect the kidneys. (You should discuss this, and how to manage your diabetes over this period, in more detail with your doctor.)
Adaptations to patient preparation will be required for certain groups of patients e.g. children, diabetics and patients with other predisposing medical conditions, in line with current department practice.
Additional projections:
Inspiratory, expiratory and oblique may be required to demonstrate the relationship of opacities and filling defects to the renal.
Tomography may be required to accurately demonstrate the renal outline and overcome shadowing from the gastro intestinal tract.
Prone, films may be required to investigate pelvic ureteric and ureteric obstruction as the heavy contrast laden urine will more readily gravitate to the site of the obstruction.
Rapid sequence films may be taken in cases of suspected renal hypertension to evaluate differential rates of contrast excretion.
Delayed films may be taken for up to 24 hours in order to demonstrate the actual site of ureteric obstruction.
Radiographic appearances during intravenous urography:
Immediate post-injection radiography:
A film taken immediately after injection of contrast should demonstrate the kidneys increased in density because of the contrast within the nephrons. If either kidney is not see in the normal place and has not be visualized on the control film a full abdomen film will demonstrate an ectopic kidney, common sites are low in the pelvis or low down on the same side as one visualized in cross duplex situation. Different density nephrograms may indicate renal artery stenosis, if this is suspected a series of films at 1min. 2min. 3min after injection may aid more accurate visualization. The kidney outline should be smooth, any irregularity may indicate a scar or a mass, a mass or bulge in the outline which does not concentrate contrast is likely to be cystic whilst one concentrating the medium will more likely be a tumor.
Five / Ten minute film
At this stage the calyces, renal pelvis and part of the ureters will be visible. There is considerable anatomical variation in the number and pattern of the renal calyces but they are normally reasonably symmetrical. The nephrogram will be reduced but both kidneys should have the same density. If one or both kidneys appear to have two separate groups of calyces then there may well be duplex collecting systems and ureters. When one kidney is denser than the other, this is due to persistence of the contrast media within the kidney (persistent nephrogram) and suggests ureteric abstruction. The pelvic-calyceal system is not filled or apparent a delayed film of that side should be taken 45-60 minutes after injection or later if required, determining the site of obstruction.
About the procedure
The procedure takes 40 to 60 minutes. You will be asked to empty your bladder before the test. In a private cubicle, you may ask to remove your clothes and put on a hospital gown. You will be taken to the x-ray room and asked to lie down on the table. Your radiographer will take the first x-ray pictures of your abdomen (tummy) without the dye. Your radiographer will then inject the dye into your hand or harm, and take more x-rays of your abdomen and pelvis. You may be asked to move position and lie on your stomach (prone), or hold your breath for a few second while the x-rays are taken. To help improve images of the kidneys, a tight band may be placed across your abdomen. You may also be asked to go to the toilet to empty your bladder and have another x-ray taken. To help improve images of the kidneys, a tight band may be placed across your abdomen. You may also be asked go to the toilet to empty your bladder and have another x-ray taken.
Contrast agents and drugs:
Typical examples for a 70kg adult with normal blood urea values (2.5 – 7.5mmol/L.)
Contrast media must be warmed to body temperature before injection.
Product
main constituent
Iodine mg/ ml
Dose
Route
Niopam 300
Lopamidol
300
50ml.
I.V
Omnipaque 350
Lohexhol
350
50ml.
I.V
Urograffin 370
Diatrozates
370
50ml.
I.V
Typical Exposure Values: (Dose = Typical Dose from N.R.P.B)
Projection
Kv
mAS
F.F.D.
Grid
Film/Screen
AP Abdomen
65-75
50-70
100cm
Broad
Regular
Tomogram20o @ 9cm
60-75
70-120
100cm
Broad
Regular
Technique:
The median cubital vein is punctured with a 19 gauge needle and and the warmed (40oC)
Contrast agent is injected rapidly. Films are then taken at intervals to demonstrate the whole of the renal tract.
What to expect afterwards
When you fell ready, you will be able to go home. You will be able to drive if you wish. You shouldn’t have any problems passing urine or see any change in the colour of your urine after the test. If this does happen ask your GP for advice. A radiologist (a doctor specialized in using imaging to diagnose medical conditions) will examine the images and send a report to the doctor who requested your test. The report can take a few days to reach your doctor. Before you go home, the radiographer may tell you when you can expect to get your result. If you haven’t been told the result of your test within two weeks, call the doctor who requested your test.
What are the risks?
Intravenous urogarphy are commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications. You will be exposed to some x-ray radiation. The level of radiation you receive during the urogram is about the same as the background radiation that you would get naturally from the environment over about 14 months. If you’re pregnant you should not have x-rays, as there is a risk that the radiation may cause some damage to your unborn child. If you are, of think you may be pregnant, tell your doctor before your appointment.
Intravenous urography done
You will be asked to wear a gown and toile on a couch. Contrast dye is then injected into a vein in your hand or harm. This may sting a little. The dye then starts to filter through the kidneys into the ureters. A series of x-ray pictures is taken over abdomen, usually every 5-10 minutes. You stay on the couch between each x-ray picture, but you may be asked to get up empty your bladder before the final x-ray picture is taken. The procedure usually takes about 30-60 minutes. However, some pictures may be taken hours later in certain circumstances.
You should be able to go home as soon as the procedure is finished. You can eat normally straight afterwards.
Side-effects
These are the unwanted but mostly temporary effects of a successful procedure. Very rarely, you may get a warm felling, some mild itching or a metallic taste in your mouth after having the dye injected. This should last only a minute or two.
When the dye is injected you may get a flushing or warm felling, and metallic taste in the mouth. These usually quickly go. Acute kidney failure is a rare complication.
An allergic reaction to the dye occurs in a small number of cases. Symptoms may be mild – for example, breathing difficulties and collapse due to low blood pressure. It has to be stressed that severe reactions are rare, and the hospital department doing the procedure will have access to full resuscitation equipment, should it be needed.
Complications
This is when problems occur during or after the procedure. It’s possible to have an allergic reaction to the dye. If you experience any itching or difficulty in breathing, tell your radiographer immediately. Medicines are available to treat an allergic reaction. The exact risks are specific to you and will differ for every person, so we haven’t included statistics here. Ask your doctor to explain how these risks apply to you.
Conclusions
A tailored urographic study allowing optimal visualization of sequentially opacities portions of the urinary tract may provide diagnostic detail in certain portions of the urinary system beyond the current capabilities of other imaging modalities. This can be accomplished only with good technique, an understanding of the limitations of the procedure, and adherence to basic rules of interpretation. The ability to correlate urogarphic findings with those from other imaging modalities will remain an important skill until an ideal ‘global’ urinary tract imaging technique emerges.
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