Contrast Solutions

what are contrast materials?

Contrast materials, also called contrast agents or contrast media, are used to improve pictures of the inside of the body produced by x-rays, computed tomography (CT), magnetic resonance (MR) imaging, and ultrasound. Often, contrast materials allow the radiologist to distinguish normal from abnormal conditions. Contrast materials are not dyes that permanently discolor internal organs. They are substances that temporarily change the way x-rays or other imaging tools interact with the body.

When introduced into the body prior to an imaging exam, 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. Contrast materials enter the body in one of three ways. They can be:

swallowed (taken by mouth or orally)
administered by enema (given rectally)
injected into a blood vessel (vein or artery; also called given intravenously or intra-arterially)

Following an imaging exam with contrast material, the material is absorbed by the body or eliminated through urine or bowel movements.

There are several types of contrast materials(liquids):

Iodine-based and barium-sulfate compounds are used in x-ray and computed tomography (CT) imaging exams.
Barium-sulfate is the most common contrast material taken by mouth, or orally. It is also used rectally and is available in several forms, including: powder, which is mixed with water before administration liquid paste tablet
Gadolinium is the key component of the contrast material most often used in magnetic resonance (MR) exams. When this substance is present in the body, it alters the magnetic properties of nearby water molecules, which enhances the quality of MR images.
Saline (salt water) and gas (such as air) are also used as contrast materials in imaging exams. Microbubbles and microspheres have been administered for ultrasound imaging exams, particularly exams of the heart.

Which imaging exams use contrast materials?

Oral Contrast Materials

Barium-sulfate contrast materials that are swallowed or administered by mouth (orally) are used to enhance x-ray and CT images of the gastrointestinal (GI) tract, including:

pharynx
Esophagus
stomach
the small intestine
the large intestine (colon)

In some situations, iodine-based contrast materials are substituted for barium-sulfate contrast materials for oral administration.

Rectal Contrast Materials

Barium-sulfate contrast materials that are administered by enema (rectally) are used to enhance x-ray and CT images of the lower gastrointestinal (GI) tract (colon and rectum). In some situations, iodine-based contrast materials are substituted for barium-sulfate contrast materials for rectal administration.

Intravenous Contrast Materials Iodine-based and Gadolinium-based

Iodine-based contrast materials injected into a vein (intravenously) are used to 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 vessels in the brain, neck, chest, abdomen, pelvis and
legs soft tissues of the body, including the muscles, fat and skin brain breast

How safe are contrast materials?

Contrast materials are safe drugs; adverse reactions ranging from mild to severe do occur but severe reactions are very uncommon. While serious allergic or other reactions to contrast materials are rare, radiology departments are well-equipped to deal with them.

How should I prepare for my imaging procedure with contrast material?

Because contrast materials carry a slight risk of causing an allergic reaction or adverse reaction, you should tell your doctor about:

allergies to contrast materials, food, drugs, 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 your exam.

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