Contrast Radiography a.

powder, which is mixed with water before

administration
is a method of studying organs using X-rays and the b. liquid
administration of a special dye, called a contrast medium. This c. paste
test allows the radiologist to evaluate structures that are not  d. tablet
clearly evident on conventional X-ray exams. Following an imaging exam with given
taken by
mouthcontrast
or orally material, the When iodine-based and barium-sulfate
intravenously orcontrast materials are
X-rays work by passing through the body. Because bones material is absorbed by the body or eliminated present in a specific area ofintra-arterially
the body, they block or limit the
block the X-rays easily, they show up clearly. But organs and through urine or bowel movements. ability of x-rays to pass through. As a result, blood vessels,
other tissue – such as blood vessels, the stomach, and the organs and other body tissue that temporarily contain iodine-
colon – do not block the X-rays so easily. The contrast medium There are several types of contrast materials: based or barium compounds change their appearance on x-
highlights these specific areas in the body and helps them to ray or CT images.
be seen in greater detail on the X-ray image. 1. Iodine-based and barium-sulfate compounds
are used in x-ray and computed tomography (CT) 3. Gadolinium is the key component of the contrast
CONTRAST MEDIA imaging exams. Contrast materials can have a material most often used in magnetic resonance (MR) exams.
Contrast Materials chemical structure that includes iodine, a naturally When this substance is present in the body, it alters the
occurring chemical element. These contrast materials magnetic properties of nearby water molecules, which
Contrast materials, also called contrast agents or contrast can be injected into veins or arteries, within the disks enhances the quality of MR images.
media, are used to improve pictures of the inside of the body or the fluid spaces of the spine, and into other body
produced by x-rays, computed tomography (CT), magnetic cavities. 4. Saline (salt water) and gas (such as air) are also used
resonance (MR) imaging, and ultrasound. Often, contrast as contrast materials in imaging exams. Microbubbles and
materials allow the radiologist to distinguish normal from microspheres have been administered for ultrasound imaging
abnormal conditions. exams, particularly exams of the heart.

Contrast materials are not dyes that permanently discolor

internal organs. They are substances that temporarily change computed
Iodine-based x-ray
the way x-rays or other imaging tools interact with the body. tomography (CT)
When introduced into the body prior to an imaging exam, contrast imaging exams
contrast materials make certain structures or tissues in the
body appear different on the images than they would if no
contrast material had been administered. Contrast materials
help distinguish or "contrast" selected areas of the body from
surrounding tissue. By improving the visibility of specific
organs, blood vessels or tissues, contrast materials help
physicians diagnose medical conditions.   MYELOG
RAPHY
Contrast materials enter the body in one of three ways. They
can be: 2. Barium-sulfate is the most common contrast
1. swallowed (taken by mouth or orally) material taken by mouth, or orally. It is also used
2. administered by enema (given rectally) rectally and is available in several forms, including:
3. injected into a blood vessel (vein or artery;
also called given intravenously or intra-arterially)
 small intestine enhance x-ray and CT images. Gadolinium injected into a vein
(intravenously) is used to enhance MR images. Typically, they
are used to enhance the:
• internal organs, including the heart, lungs,
liver, adrenal glands, kidneys, pancreas, gallbladder, spleen,
uterus, and bladder
• gastrointestinal tract, including the stomach,
small intestine and large intestine
• arteries and veins of the body, including
Which imaging exams use contrast materials? vessels in the brain, neck, chest, abdomen, pelvis and legs
1. Oral Contrast Materials • soft tissues of the body, including the
o Barium-sulfate contrast materials that are colon muscles, fat and skin
swallowed or administered by mouth (orally) are used to • brain
 In some situations, iodine-based contrast • breast
enhance x-ray and CT images of the gastrointestinal (GI)
materials are substituted for barium-sulfate
tract, including: contrast materials for oral administration. Contrast materials are safe drugs; adverse reactions ranging
a. pharynx
from mild to severe do occur but severe reactions are very
b. esophagus 2. Rectal Contrast Materials uncommon. While serious allergic or other reactions to
c. stomach contrast materials are rare, radiology departments are well-
d. the small intestine o Barium-sulfate contrast materials equipped to deal with them.
e. the large intestine (colon) that are administered by enema (rectally) are used to
enhance x-ray and CT images of the lower Because contrast materials carry a slight risk of causing an
pharynx gastrointestinal (GI) tract (colon and rectum). allergic reaction or adverse reaction, you should tell your
In some situations, iodine-based contrast materials doctor about:
are substituted for barium-sulfate contrast materials • allergies to contrast materials, food, drugs,
for rectal administration. dyes, preservatives, or animals
• medications you are taking, including herbal
supplements
• recent illnesses, surgeries, or other medical
conditions
• history of asthma and hay fever
• history of heart disease, diabetes, kidney
disease, thyroid problems or sickle cell anemia
You will be given specific instructions on how to prepare for
Esophagus your exam.

stomach 3. Intravenous Contrast Materials

o Iodine-based and Gadolinium-
based

o Iodine-based contrast materials

injected into a vein (intravenously) are used to
 Most are mild, but severe rashes may require
Side effects and adverse and allergic reactions medication after discussion with your physician.
Barium Sulfate Contrast Materials MILD REACTION At-Risk Patients
• nausea and vomiting
You should tell your doctor if these mild side effects of • headache Some conditions increase the risk of an allergic or adverse
barium-sulfate contrast materials become severe or do not go • itching reaction to iodine-based contrast materials. These include:
away: • flushing
• stomach cramps • mild skin rash or hives • previous adverse reactions to iodine-based
• diarrhea contrast materials
• nausea MODERATE REACTION • history of asthma
• vomiting • severe skin rash or hives • history of allergy
• constipation • wheezing • heart disease
• abnormal heart rhythms • dehydration
• high or low blood pressure • sickle cell anemia, polycythemia and
Tell your doctor immediately about any of these symptoms: • shortness of breath or difficulty myeloma
• hives breathing • renal disease
• itching • the use of medications such as Beta
• red skin SEVERE REACTION blockers, NSAIDs, interleukin 2
• swelling of the throat • difficulty breathing • having received a large amount of contrast
• difficulty breathing or swallowing • cardiac arrest material within the past 24 hours
• hoarseness • swelling of the throat or other parts
• agitation of the body Being at increased risk for an allergic or adverse reaction to
• confusion • convulsions contrast material does not necessarily mean a patient cannot
• fast heartbeat • profound low blood pressure undergo an imaging exam with contrast materials.
• bluish skin color Medications are sometimes given before the contrast material
Contrast-Induced Nephropathy is administered to lessen the risk of an allergic reaction in
You are at greater risk of an adverse reaction to barium- susceptible patients.
sulfate contrast materials if: Patients with impaired kidney (renal) function should
• you have a history of asthma, hay fever, or be given special consideration before receiving MR-Gadolinium
other allergies, which will increase your risk of an iodine-based contrast materials by vein or artery.
allergic reaction to the additives in the barium-sulfate agent. Such patients are at risk for developing contrast- The contrast material used in MR called gadolinium is less
• you have cystic fibrosis, which will increase induced nephropathy (CIN), a condition in which likely to produce an allergic reaction than the iodine-based
the risk of blockage in the small bowel. already-impaired kidney function worsens within a materials used for x-rays and CT scanning. Very rarely,
• you are severely dehydrated, which may few days of contrast material administration. Much patients are allergic to gadolinium-based contrast materials
cause severe constipation. of the research linking CIN with iodine-based contrast and experience hives and itchy eyes. Reactions usually are
• you have an intestinal blockage or material is based on older contrast agents that are no mild and easily controlled by medication. Severe reactions are
perforation that could made worse by a barium-sulfate agent. longer used, and some recent studies have found no rare.
increased risk of CIN in patients who received iodine-
A very small percentage of patients may develop a based contrast material. If you have impaired kidney
delayed reaction with a rash which can occur hours to days function, your doctor will assess the benefits of
after an imaging exam with an iodine-based contrast material. contrast-enhanced CT against any risks
 Gadolinium-based Contrast Material Intravenous Contrast Material (Iodine and
 What will I experience before and after Gadolinium) and Breast-feeding:
receiving contrast material? When the gadolinium is injected, it is normal to feel
coolness at the site of injection, usually the arm for a Manufacturers of intravenous contrast indicate mothers
minute or two. should not breast-feed their babies for 24 to 48 hours after
Barium-Sulfate Oral and Rectal Contrast Material The needle may cause you some discomfort when it contrast medium is given. However, both the American
is inserted. Once it is removed, you may experience College of Radiology (ACR) and the European Society of
If a barium-sulfate contrast material (given orally or rectally) some bruising.
will be used during your exam, you will be asked not to eat for Urogenital Radiology note that the available data suggest that
Increased fluid intake will help eliminate the contrast it is safe to continue breast-feeding after receiving
several hours before your exam begins. If the contrast material from your body. IV contrast is usually
material will be given rectally, you may also be asked to intravenous contrast. The Manual on Contrast Media from the
excreted by the kidneys within the next 24 hours ACR states:
cleanse your colon with a special diet and medication (assuming normal renal function).
(possibly including an enema) before your exam.
If you swallow the contrast material, you may find the taste "Review of the literature shows no evidence to suggest that
Oral contrast is usually excreted within a day or two, oral ingestion by an infant of the tiny amount of gadolinium
mildly unpleasant; however, most patients can easily tolerate but in people with constipation it may not completely
it. contrast medium excreted into breast milk would cause toxic
clear out for several days. There is no radiation in effects. We believe, therefore, that the available data suggest
contrast used for CT. that it is safe for the mother and infant to continue breast-
If your contrast material is given by enema, you can expect to
experience a sense of abdominal fullness and an increasing feeding after receiving such an agent.
need to expel the liquid. The mild discomfort will not last long.
Pregnancy and contrast materials
It is a good idea to increase your fluid intake after an imaging If the mother remains concerned about any potential ill
exam involving a barium-based contrast material to help Prior to any imaging exam, women should always effects, she should be given the opportunity to make an
remove the contrast material from your body. inform their physician or x-ray technologist if there is informed decision as to whether to continue or temporarily
Barium-sulfate contrast materials are expelled from the body any possibility that they are pregnant. Many imaging abstain from breast-feeding after receiving a gadolinium
with feces. You can expect bowel movements to be white for tests and contrast material administrations are contrast medium. If the mother so desires, she may abstain
a few days. Some patients may experience changes in their avoided during pregnancy to minimize risk to the from breast-feeding for 24 hours with active expression and
normal bowel movement patterns for the first 12 to 24 hours. baby. discarding of breast milk from both breasts during that period.
In anticipation of this, she may wish to use a breast pump to
For CT imaging, if a pregnant woman must undergo obtain milk before the contrast study to feed the infant during
Iodine-based Contrast Material imaging with an iodine-based contrast material, the the 24-hour period following the examination."
patient should have a discussion with her referring
When an iodine-based contrast material is injected into your physician and radiologist to understand the potential
bloodstream, you may have a warm, flushed sensation and a risks and benefits of the contrast-enhanced scan.
metallic taste in your mouth that lasts for a few minutes.
The needle may cause you some discomfort when it is For MR imaging, gadolinium contrast material
inserted. Once it is removed, you may experience some administration is usually avoided due to unknown
bruising. risk to the baby, but may be used when critical
It is a good idea to increase your fluid intake after an imaging information must be obtained that is only available
exam involving an iodine-based contrast material to help with the use of gadolinium-based contrast material.
remove the contrast material from your body.