What is Intravenous Urography?
Intravenous Urography examines is the urinary system by using a special dye (contrast medium) that is injected into one of your veins. The dye travels through the bloodstream and is removed by the kidneys and passed into the 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 can show kidney and bladder stones, tumours, blood clots or narrowing in the ureters. It is routinely done as an out-patient procedure in the radiology department. The procedure is comprised of two phases.
First, it needs a functioning kidney to clean the dye out of the blood into the urine. The time necessary for the dye to come into view on x rays correlate exactly with kidney’s function.
The second phase gives entire anatomical images of the urinary tract. Within the first few minutes the dye “lights up” the kidneys, a stage called the nephrogram.
Later the pictures follow the dye down the ureters and into the bladder. The final film taken after urinating shows how well the bladder empties. The contrast is removed from the bloodstream through the kidneys. Then contrast media becomes visible on x-rays almost immediately after injection. Attention is paid at the:
Tubes that connect them (urethras)
Why Intravenous Urography is done?
The most common reason an IVU is done is in a condition be the suspected presence of stones in the urinary tract. Other pathology are such as renal failure, myeloma and infancy. The doctor would like to know how the urine is draining from the kidney to the bladder and how the stones have affected your urinary system. This may be used to balance the ultrasound of the kidney to the bladder and how the stones have affected the urinary system and the other wise.
IVU uses a dye, also called as a contrast medium. This shows up the soft tissues the urinary system on the x-ray. This will allow the cancer to be seen in any parts of the patient’s urinary system. The cancer shows up as a blockage or an uneven outline on the wall of the bladder or ureter for an example. It is also used in the investigation of other suspected causes of urine “obstruction” or blood in the urine.
Patient preparation for Intravenous Urography.
Patient should be held NPO for 24 hours prior to the radiographic study.
Patient should receive a minimum of 2 cleansing enemas prior to study. One enema should be performed the night before the procedure.
Patient should receive large-bore catheter prior to examination start time. Patients over 60 lbs should receive 2 large-bore catheters to facilitate contrast administration.
A) Unless the patient have an asthma or other allergies the medications are not reqiured. Therefore, the suggestion for the examination is reviewed since the patient can develop a reaction towards the contrast media that are used. If the doctor feels the benefits of this procedure will equalize the risks, then the patient may be arranged to prednisolone (a type of steroid medication) tablets for the examination. This would be 40 mg 12 hours and then, 40mg 2 hours prior to the procedure. Sometimes in an urgent examination, the patient may be given an injection of Hydrocortisone 100 mg (another type of steroid) just before the the examination.
B) If the IVU procedure is in the afternoon, patient can take light breakfast. Until 4-6 hours before the procedure, the patient can take a small cup of clear fluids per hour such as water, fruit juice, black tea or black coffee. No milk must be taken because it causes indigestion. It is preferable that nothing should 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.
C) Low residue vegetable-free diet for 1 day before the examination. A lot of water should be taken during this period before fasting begins. The patient may be given laxatives such as 2 tablets of Dulcolax at 9 pm the night before the examination to increase the peristalsis action.
Procedure for Intravenous Urogram.
Patient will be asked to lie on an x-ray table where the radiographer will take a preliminary film of their abdomen. The doctor will then give patient an injection of contrast medium into their arm. After this, a series of films will be taken over the next 30 minutes as the dye passes through your renal tract. At one stage of the procedure, a tight band may be placed on patient’s lower abdomen to help the radiographer to obtain maximum filling of the kidneys before the contrast medium flows down into the bladder. At the end of the examination, patient will be asked to empty your bladder, and then another film will be taken to see the empty bladder. Sometimes the contrast medium takes some time to go through the kidneys and these results in an extended examination time. Contrast medium is a fluid that is opaque to x-rays, is concentrated in the kidneys and goes into the bladder before being passed out in your urine. It is colorless, so the patient cannot see it when you go to the toilet. Aside from the minor sting from the injection as the contrast medium is injected, some people report feeling a warm flush, and sometimes have a metallic taste in their mouth. These things usually disappear within a minute or two, and are no cause for alarm. Incase the patient become itchy or short of breath, let the radiologist know straight away, as they may have a slight reaction to the contrast, which can be eased with antihistamines. If the patient have asthma or severe allergies, the radiologist may suggest them to take a steroid, or use other imaging options.
Patient care after Procedure
Sometimes, there would be minor (generalised warmth, to rashes) to moderate, asthma and difficulty breathing, a drop in the blood pressure (usually transient) or rarely severe and life threatening (anaphylaxis). Infrequently, there may be severe discomfort/pain when compression is applied, but usually the compression will be released the moment the patient inform the radiographer in charge of your examination. The only severe complication of an IVP is an allergy to the iodine-containing dye that is used. Such an allergy is rare, but it can be fatal.
Patient are given and asked to lay on top of draw sheets cause the radiographic may be cold. Pillows are given for comfort. There is usually no special instructions post IVU. The patient may eat and drink unless your referring doctor has another examination or procedure for you after the IVU examination
About the Intravenous Urography Examination
The procedure takes about 40 to 60 minutes. Patient need to empty their bladder before the test. In a private cubicle, Patient may be asked to remove their clothing and put on a hospital gown. Then patient will be taken to the X-ray room and asked to lie down on the X-ray table. Radiographer will take the first X-ray pictures without the dye. Radiographer will then inject the dye in a vein in their hand or arm, and take more X-rays of your abdomen and pelvis. Patient may be asked to move position and lie on your stomach, or hold their breath for a few seconds while the X-rays are taken. To help improve images of the kidneys, a tight band may be placed across their abdomen. Patient may also be asked to go the toilet to empty your bladder and have another X-ray taken.
Results on Intravenous Urography
A normal intravenous urogram indicates no visible abnormality in the structure or function of the urinary system. The radiologist looks for a smooth non-lobulated outline of each kidney, no clubbing or other abnormality of the renal calyces (collecting system), and no abnormal fluid collection in the kidneys that could suggest obstruction. The ureters must contain no filling defects (stones) or deviations due to an adjacent tumor. The bladder must have a smooth outline and empty normally as visualized on the post-void film.
Abnormal results include hydronephrosis (distension of the renal pelvis and calices due to obstruction) as a result of tumors or calculi (stones). Cysts or abscesses may also be present in the urinary system. A delay in renal function can also indicate renal disease. An abnormal amount of urine in the bladder after voiding may indicate prostate or bladder problems.
Intravenous urograms are often done on children to rule out a rapid developing tumor in the kidneys, called a Wilm’s tumor. Children are also prone to infections of the bladder and kidneys due to urinary reflux (return back-flow of urine).
For a preliminary film, (35 x 43cm) supine full A.P. abdomen to include lower border of symphysis pubis and diaphragm, abdominal preparation,and for any calcifications overlying the renal tract areas. Additional films to decide position of any opacities.35A° posterior oblique of the renal regions. Tomogram of the renal areas are at 8-11 cm
4 reasom why we do preminilary
The position of kidney (collimation)
For an immediate film (24 x 30cm), AP of the renal areas, the film is exposed 10-14 s after the injection (arm-to-kidney time). It is to show the nephrogram.
For a 5 minute film (24 x 30cm) AP of the renal areas, this film is taken to decide if the excretion is equal or if the uptake is poor and is important for assessing the need to adjust the technique. A compression band is now applied around the patient’s abdomen and the balloon positioned midway between the iliac spines. This can produce better pelvicalyceal distension. Compression should not be used in cases of suspected renal colic, renal trauma or after recent abdominal surgery.
In 15 minute AP of the renal areas, there is usually sufficient distension of the pelvicalyceal system with opaque urine by the time. In the release of film the supine AP abdomen, this film is taken to show the whole urinary tract. If the film is good enough, the patient is asked to empty their bladder. The main value of this film is to access bladder emptying to demonstrate a return to normal of the dilated upper tracts with the relief of bladder pressure.
In 25 Minute film (24 x 30cm) 15A° caudal angulations centred 5 cm above the upper border of the symphysis pubis to reveal the swollen bladder.
After micturition film, this will be the coned view of the bladder with the tube angled 15 caudad and centred 5cm above the symphysis pubis or the full length abdominal film to show the bladder emptying success and the return of the previously swollen lower ends of urethras to normal.
Contrast agents and drugs
Common examples for a 70 kg adult with normal blood urea values (2.5 – 7.5mmol/L.)Contrast media must be warmed to body temperature before injection.
High osmolarity of contrast medium (HOCM) or low osmolarity of contrast medium (LOCM) 370 are acceptable but infants and small children, those with renal and cardiac failure, poorly hydrated patients, patients with diabetes, myelomatosis or sickle-cell anaemia and patient who have had a previous severe contrast medium reaction with low osmolarity contrast medium reaction with a strong allergic history have to receive low osmolarity contrast medium. Paediatric dose is 1ml kg/1
Equipment used for Intravenous Urogram
Conray 400A® — 1 mL / lb ( 3 mL / kg)
In high risk cats or compromised dogs (abnormal BUN / Creatinine), consult with the radiologist about the use of Omnipaque (Iohexol) instead of the Conray.
Indwelling catheter preplaced in patient by clinician, student or treatment room techs. Depending on size of the animal or amount of contrast to be injected, 2 catheters might be required.
Crash kit should be made available in the case of allergic contrast reaction (ie: vomiting and / or nausea are the most common.)
What are the risks on doing Intravenous Urogram?
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 of this procedure .Patient will be exposed to some X-ray radiation. Level of exposure is about the same as the background radiation that you would receive naturally from the environment over 12 to 14 months. Pregnant women are advised not to have X-rays, as there is a risk the radiation may affect the development of your unborn child. If the patient is, or think you may be pregnant, they must tell their doctor before the appointment. These are the unwanted but mostly temporary effects of a successful procedure. Very rarely, they may sense a warm feeling or get a metallic taste in their mouth after having the contrast. This should last only a minute or two.