| Radiography - Intravenous Pyelogram
What is an Intravenous Pyelogram (IVP)? Back to Top
An
Intravenous Pyelogram (IVP) is an x-ray examination of the kidneys,
ureters and urinary bladder. Most people are familiar with x-ray
images, which produce a still picture of the body's interior by passing
small, highly controlled amounts of radiation through the body and
capturing the resulting shadows and reflections on film. An IVP study
uses a contrast material (iodine) to enhance the x-ray images. The
contrast material is injected into the patient's system and its
progress through the urinary tract is then recorded on a series of
quickly captured images. The exam enables the radiologist to review the
anatomy and the function of the kidneys and urinary tract.
What are some common uses of IVP studies? Back to Top
A
radiologist can use an IVP study to find the cause of a wide variety of
disorders, including frequent urination, blood in the urine, or pain in
the side or lower back. The IVP exam can enable the radiologist to
detect problems within your urinary tract resulting from kidney stones;
enlarged prostate; tumors in the kidney, ureters or urinary bladder;
and other changes.
How should I prepare for the procedure? Back to Top
You
should tell your doctor about any allergies you have to foods or
medications, as well as any recent illnesses or other medical
conditions. If you are diabetic make sure your doctor is aware of your
condition and the medications you take. Women should always inform
their doctor or x-ray technologist if there is any possibility that
they are pregnant.
Your doctor will give you detailed instructions on how to prepare
for your IVP study. You will likely be instructed not to eat or drink
after midnight the night before your exam. You may also be asked to
take a mild laxative (in either pill or liquid form) the evening before
the procedure. Follow your doctor's instructions.
Once you arrive at the imaging center you will be asked to change
into a gown before your examination. You will also be asked to remove
jewelry, eyeglasses or any metal objects that could obscure the images.
Underwear with metallic components should also be removed.
What does the x-ray equipment look like? Back to Top
The
equipment used for most IVP examinations consists of a large, flat
table. Suspended above the table is an apparatus containing the x-ray
tube. The apparatus moves on a jointed "arm" so that it can be properly
positioned.
How does the procedure work? Back to Top
Different tissues
such as bone, blood vessels, and muscles and other soft tissues absorb
x-ray radiation at different rates. When a special film plate is
exposed to the absorbed x-rays an image of the inside of the body is
captured.
An IVP study requires the use of a contrast material injected
intravenously to help tissues show more clearly on the x-ray film. As
the contrast material moves into and through the kidneys, ureters and
urinary bladder, the technologist captures a series of images that
track its progress. The technologist may apply a compression band
around the body to better visualize the urinary structures leading from
the kidney. By reviewing these images a radiologist can assess
abnormalities in the urinary system, as well as how quickly and
efficiently the patient's system is able to handle waste.
How is the procedure performed? Back to Top
Before
introducing the contrast material, the radiologist or technologist will
ask whether the patient has any allergies and whether the patient has a
history of diabetes, asthma, a heart condition, kidney problems or
thyroid conditions. These conditions may indicate a higher risk of
reaction to the contrast material or potential problems eliminating the
material from the patient's system after the exam. You may also be
asked if you have had any prior surgery on the urinary system.
An IVP examination is usually done on an outpatient basis. The
patient is positioned on the table and a contrast material is injected,
usually in a vein in the patient's arm. Contrast (iodine) excreted in
the urine shows outlines of the kidneys and demonstrates the inner
"collecting system" and ureters as well. The inner structures appear
white in the image. Images are taken before and after the injection of
the contrast material. As the contrast material is processed by the
kidneys a series of images is captured to determine the actual size of
the kidneys and to show the collecting system as it begins to empty.
Some kidneys don't empty at the same rate and delayed films from 30
minutes to three or four hours may be requested. However, a typical IVP
study usually takes about an hour.
What will I experience during the procedure? Back to Top
Aside
from a minor sting from the injection of contrast material an IVP
causes no pain. When the contrast material is injected, some people
report feeling a flush of heat and sometimes a metallic taste in their
mouth. These common side effects usually disappear within a minute or
two and are no cause for alarm. Some people experience a mild itching
sensation. If it persists or is accompanied by hives, the itch can be
treated easily with medication. In rare cases a patient may become
short of breath or experience swelling in the throat or other parts of
the body. These can be indications of a more serious reaction to the
contrast material that should be treated promptly, so tell the
radiologist immediately if you experience these symptoms.
During the imaging process you may be asked to turn from side to
side and to hold several different positions to enable the radiologist
to capture views from several angles. Near the end of the exam you may
be asked to empty your bladder so that an additional film can be taken
of your urinary bladder after it empties.
The contrast material used for IVP studies will not discolor your
urine or cause any discomfort when you urinate. If you experience such
symptoms after your IVP exam, they are likely to indicate some other
problem. Let your doctor know right away.
Who interprets the results and how do I get them? Back to Top
A
radiologist, who is a physician experienced in IVP and other radiology
examinations, will analyze the images and send a signed report with his
or her interpretation to the patient's primary care physician. The
patient receives IVP results from the referring physician who ordered
the test results. New technology also allows for distribution of
diagnostic reports and referral images over the Internet at many
facilities.
What are the benefits vs. risks? Back to Top
Benefits
- IVP images provide valuable, detailed information to
assist physicians in diagnosing and treating urinary tract conditions
from stones to cancer.
- Imaging of the urinary tract with IVP is a minimally invasive procedure with rare complications.
- An
IVP can often provide enough information about stones and obstructions
to direct treatment with medication and avoid more invasive surgical
procedures.
- The imaging process is fast, painless
and less expensive than alternatives such as computed tomography (CT)
and magnetic resonance imaging (MRI).
Risks
- Contrast materials used in IVP studies can cause adverse reactions in some people.
- Special
care is taken during x-ray examinations to ensure maximum safety for
the patient by shielding the abdomen and pelvis with a lead apron, with
the exception of those examinations in which the abdomen and pelvis are
being imaged. Women should always inform their doctor or x-ray
technologist if there is any possibility that they are pregnant.
- The
effective radiation dose from this procedure is about 1.6 mSv, which is
about the same as the average person receives from background radiation
in six months. See the Safety page for more information about radiation
dose.
- Radiation risks are further minimized by:
- The use of high-speed x-ray film that does not require much radiation to produce an optimal image.
- Technique
standards established by national and international guidelines that
have been designed and are continually reviewed by national and
international radiology protection councils.
- Modern,
state-of-the-art x-ray systems that have very tightly controlled x-ray
beams with significant filtration and x-ray dose control methods. Thus,
scatter or stray radiation is minimized and those parts of a patient's
body not being imaged receive minimal exposure.
What are the limitations of IVP studies? Back to Top
An IVP
shows details of the inside of the urinary tract including the kidneys,
ureters and bladder. CT or MRI may add valuable information about the
functioning tissue of the kidneys and the surface and surrounding
structures nearby the kidneys, ureters and bladder. IVP studies are not
usually indicated for pregnant women. Back to Top |
