Intravenous Pyelography
Special Procedures/IVP
Intravenous Pyelography (IVP) or Intravenous Urography (IVU), is the radio-graphic examination of urinary tract including renal parenchyma calyx and pelvis after intravenous injection or oral intake of contrast media. It is a true renal function test because the contrast media molecules are rapidly remove from the blood streams and are excreted completely by a normal kidney.
Intravenous pyelography is the most commonly used investigation for evaluation of the urinary system. Before starting the procedure, it is important to have a well prepared patient. The patient should have a low residual diet for 1-2 days, a light evening meal and nil orally after midnight. He should subsequently report fasting, to the radiology department. In addition it is important to give gases absorbent i.e. Tab. charcoal 2 TDS, a day before and a good laxative in the night before the day of examination to clear the large bowel of gases and faecal matter respectively. Under no circumstances should the patient be dehydrated as this can have serious complications in our tropical climate. However, fluids must not be restricted for infants and diabetic patients.
Indications of IVP are as follows:
1. In investigation of Hypertension.
2. Function of Kidney.
3. Congenital anomalies involving kidneys.
4. In suspected obstructive uropathies like stone etc.
5. In suspecting abdominal mass lesion arising from kidney.
6. In blunt injuries of abdomen with Haematuria.
7. Calculus.
8. Renal colic or flank pain.
9. Abnormalities of ureter.
Contra-indications of IVP are as follows:
1. Iodine sensitivity or previous reaction to contrast media.
2. Pregnancy.
3. Intractable cardiac or renal failure.
4. Multiple myeloma.
Contrast medium used:
1. Low Osmolar Contrast Material (LOCM).
2. Ex. Urografin 76%.
3. Dose: 50-100ml for Adult and 1ml kg-1 for Paediatric.
Preliminary films:
The patient lies supine and a plain radio-graph of 16’’×20’’ is obtained so as to include both diaphragms above and the lower margin of the symphysis pubis.
In tall patients, one may have to use a 14’’×17’’ film. Generally the bladder area can be exposed separately on a 8’’×10’’ film. The exposures are made in arrested respiration.
The scout radiograph or the plain film demonstrates the contour of the kidneys, their location in the supine position and the presence of any renal or other calculi. This also serves to check the preparation of the GIT and to enable the technologist to make any necessary alteration in the exposure factors. A gonadal shield must be used to restrict radiation if it will not overlap the area under investigation.
Techniques used:
The contrast medium is injected intravenously either as a bolus or infusion. The patient is observed carefully during injection for any adverse effects.
Abdominal compression should be applied before injection. This serves the purpose of retaining contrast within the pelvicalyceal system and upper ureters after excretion by the kidneys.
The technologist should prepare for the first post injection exposure before the contrast is injected. The cassette is placed in the Bucky tray, side identification and time and date markers are placed on the right side by convention.
Radio-graphs are made at specified intervals from the time of the completion of injection of contrast medium.
The most frequently used procedure for IVU are one minute film to obtain a nephrogram followed by a 5 minute film for the collecting system.
Immediately after each film is exposed it is processed and reviewed to determine future exposures.
At 15 minute the abdominal compression is released and a full 15’’×12’’ exposure is obtained immediately to assess the ureters.
The prone position is recommended for the demonstration of the UPJ and for filling the obstructed ureter in the presence of hydronephrosis, using this method of releasing compression, contrast medium is seen in the greater part, if not the whole of the urters and also in the bladder. Ureteric compression is contra-indication after recent trauma or operation, acute ureteric colic or aortic aneurysm and should be avoided in patients of renal failure.
Immediately after the last AP urogram the patient may be allowed to eat. A film of the full bladder is exposed between 30-40minute after injection, to be followed by a post maturation film to assess residual urine in such conditions as small tumor masses or enlarged prostate in male patients.
Delayed Excretion used:
Views of the kidneys may be required at increasing intervals up to 24hours.
Ectopic kidney understanding:
If no kidney is seen in the renal area in the 5 minute film, an AP view of the whole abdomen should be taken.
Bladder abnormalities:
Oblique views of the bladder are required to assess intraluminal growths and diverticulae better.
Benefits of IVP Procedure:
1. Imaging of the urinary tract with IVP is a minimally invasive procedure.
2. IVP images provide valuable, detailed information to assist physicians in diagnosing and treating urinary tract conditions from kidney stones to cancer.
3. An IVP can often provide enough information about kidney stones and urinary tract obstructions to direct treatment with medication and avoid more invasive surgical procedures.
4. No radiation remains in a patient's body after an x-ray examination.
5. X-rays usually have no side effects in the typical diagnostic range for this exam.
Risks of IVP Procedure:
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
1. The effective radiation dose for this procedure varies.
2. Contrast materials used in IVP studies can cause adverse allergic reactions in some people, sometimes requiring medical treatment.
3. Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant.
Write about this article along with your queries in comment box.
Subscribe to:
Posts (Atom)