An intravenous urogram is an exam a doctor may perform in order to discover the size and placement of the kidneys and bladder, as well as check the ureters, the calyces and the pelvis for anatomical abnormalities. A dye, or contrast medium, is injected into the body. X-rays are taken to map the progress of the dye through the urinary tract, allowing the doctor to see the urinary system and look for problems. An intravenous urogram can often be performed as an outpatient procedure. It can be performed on adults and children.

The indications are:

1. for suspected renal calculi.
2. in suspected autosomal recessive polycystic kidney disease.
3. when an occult duplex kidney is considered, especially if US and ^99mTc-DMSA imaging are normal.
4. to define ureteric anatomy in the context of primary enuresis.
5. to define ureteric anatomy in known duplex kidneys.
6. if a small kidney is discovered on US or isotope examination and no VUR is found, then an IVU to show the calyceal anatomy may prove helpful in establishing the cause, e.g. previous ischaemia.
7. occasionally in the post-transplant setting to demonstrate ureteric anatomy.
8. Persistent hematuria.
9. Trauma.

IVU is contraindicated in:

(1) patient with creatinine >150 umol/L.

(2) Renal failure.

(3) Hepatic failure, which may be aggravated.

(4) Dehydration.

(5) Infancy.

(6) The first trimester of pregnancy is a relative contraindication, but the danger is   minimal.

(7) Any previous reaction to contrast medium or other allergic disease.

(8) Multiple myeloma.

(9) Cardiac failure; there is a risk of arrythmia.

Preparation:

Fasting instructions

If the procedure is in the afternoon, you can take a light breakfast. Up until 4-6 hours of the procedure, you can take a small cup of clear fluids per hour.( e.g. Water, fruit juice, black tea or black coffee). It is preferable that nothing be taken for at least 4 hours prior to the procedure. Water is allowed in diabetics, myeloma patients, renal failure and for other conditions where dehydration is contraindicated (should not be allowed).

Medication instructions

None – unless you have asthma or known allergies.

For patient with known case of asthma and allergy, you may be prescribed prednisolone tablets prior to the examination.

This would be 40 mg 12 hours before examination and then, 40mg 2 hours prior to the procedure.

Sometimes in an urgent examination, you may be “unprepared” and have a known allergy; you may be given an injection of Hydrocortisone 100 mg just prior to the examination.

Bowel preparation

Low residue vegetable-free diet for 1 day prior to the examination. Water to be taken freely during this period before fasting begins (see above). You may be given laxatives such as 2 tablets of Dulcolax at 9 pm the night before the examination.

Procedure:

An injection of x-ray contrast media is given to a patient via a needle or cannula into the vein, typically in the arm. The contrast is excreted or removed from the bloodstream via the kidneys, and the contrast media becomes visible on x-rays almost immediately after injection. X-rays are taken at specific time intervals to capture the contrast as it travels through the different parts of the urinary system. This gives a comprehensive view of the patient’s anatomy and some information on the functioning of the renal system.

Contrast agents used:

1. Visipaque ( iso-osmolar,non-ionic, water soluble ) in creatinine >100 up to 149 umol/L.
2. Omnipaque ( low osmolar contrast media, non-ionic, water soluble ) in creatinine less than 100 umol/L.
3. Gastrographin and urographin are not widely used due to toxicity if exceeded 5x serum osmolality.

What happens during IVU examination?

1. You will change into a gown for this examination and asked to empty your bladder (pass urine). You will lie on the special table and radiographs of your abdomen will be done at certain intervals.
2. Contrast will be given (via a needle through a vein in your forearm/arm) after a preliminary radiograph.
3. In the early stages, some compression (only for a few minutes) may be applied to the lower abdomen by means of pads and a belt or there may only be a head down tilt of the table.
4. In normal flow of urine from the kidney to the bladder, this procedure will take at least 30 minutes to complete. You will be asked to pass urine before the final film is taken. However, depending on your condition, there may be more films and delayed views as well.

This examination is always tailored to your urinary system function and may involve modifications and even additional drugs (e.g. diuretic) to further evaluate your condition. It may also take several hours to complete. At the end of the examination, the radiologist should be able to answer the questions that prompted your doctor to send you for an IVU!

ROUTINE IVP

Film Sequence:

Preliminary film, supine full A.P. abdomen to include lower border of

symphysis pubis and diaphragm, to check, abdominal preparation, exposure value and for any calcifications overlying the renal tract areas.

Supplementary films to determine position of any opacities.

35° posterior oblique of the renal areas.

Immediate film, A.P. of the renal areas to show the nephrogram, i.e. the

renal parenchyma opacified by the contrast medium in the renal tubules.

5 Minute film, A.P. of the renal areas to determine if excretion 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

pelvicalyceal systems to demonstrate any filling 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 (On release if compression has been applied) to

demonstrate the pelvicalyceal systems and the ureters.

25 Minute film 15° caudal angulation centred 5 cm above the upper

border of the symphysis pubis to demonstrate the distended bladder.

Post Micturition film 15° caudal angulation centred 5 cm above the

upper border of the symphysis pubis to demonstrate the bladder emptying success, and the return of the previously distended lower ends of ureters to normal.

Additional Projections:

Inspiratory, expiratory and oblique projections may be required to demonstrate the relationship of opacities and filling defects to the renal tract.

Tomography, may be required to accurately demonstrate the renal outlines and overcome shadowing from the gastro intestinal tract.

Prone films may be required to investigate pelvi 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.

What are the risks?

Intravenous urograms 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, or think you may be pregnant, tell your doctor before your appointment.

Side-effects

These are the unwanted but mostly temporary effects of a successful procedure. Very rarely, you may get a warm feeling, some mild itching or a metallic taste in your mouth after having the dye injected. This should last only a minute or two.

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.

What is the future of IVP?

The IVP is now becoming more and more obsolete. It has largely been taken over by Computed tomography (CT), which gives greater detail on anatomy and function.

Reference:

1. http://www.radiologymalaysia.org/search.html
2. IVU technique for radiographers.
3. http://www.bupa.co.uk/health_information/