CT With Contrast and MRI With Contrast: Facts to Know

September 16, 2021 – 4 min read

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CT With Contrast and MRI With Contrast: Facts to Know

Medical imaging allows radiologists to explore the hidden world of the body so they can detect any areas of concern and share those findings with your physician. One of the ways they do this is by using contrast materials—also known as contrast agents or contrast dyes.

Contrast materials are frequently used during CT scans and MRI scans as well as other types of imaging studies. They illuminate specific structures within your body so the radiologist can more easily identify abnormalities, such as diseases, tumors, inflammation, irregularities in formation and/or poor blood flow to an organ.

The purpose of contrast materials

CT scans and MRI scans with contrast can show a variety of internal structures, including:

  • Arteries
  • Bladder
  • Brain
  • Breasts
  • Colon
  • Heart
  • Intestines
  • Kidneys
  • Lungs
  • Muscles and other soft tissues
  • Rectum
  • Stomach
  • Veins

Preparing for CT with contrast and MRI with contrast

Radiologists use several types of contrast. The type you receive depends on the kind of imaging study you’ll have and it will determine how you prepare for your scan. For a CT scan with contrast, your technologist will often use an iodine-based material or a material containing barium sulfate, a type of powder. If you’re having an MRI scan with contrast, your technologist will use a contrast dye containing the element gadolinium.

No matter what type of contrast test you’ll have, notify your physician about whether you have asthma or ANY type of allergies, especially to contrast materials, but even allergies such as shellfish that may indicate a reaction to a specific form of contrast. Ensure your physician is aware of the medications you take and your medical history.

Your physician will give you specific instructions about what to do before your test, including whether you need to avoid eating or drinking.

Contrast safety

Contrast materials are safe and rarely produce side effects, such as allergic reactions. However, certain allergies and medical conditions, such as kidney disease, can increase your risk of side effects.

When we perform a CT scan with contrast or an MRI scan with contrast—or any other type of imaging test involving contrast—you can be confident that the materials are safe and that our providers have completed extensive training in administering them.

When you arrive at our center, your imaging provider will give you a medical history questionnaire that will help identify if you’re at a higher risk for complications due to contrast materials. Answer these questions carefully so your technologist is aware of your existing medications, health conditions including allergies or pregnancy, and any prior reactions to contrast.

What to expect during your imaging study

After you arrive for your scan, the imaging team will administer the contrast material. How they administer it depends on the type of contrast you need and the type of test you’ll be having.

You can take some contrast agents by mouth. They may have a slightly unpleasant taste. Most often the contrast materials will require an injection into a vein, called an intravenous (IV) injection. If you receive an IV contrast containing iodine, you may develop a metallic taste in your mouth and feel warm. Those sensations will pass after a few minutes. A gadolinium-based IV contrast may make your skin feel cool at the injection site for a few minutes.

The length of an imaging study varies from patient to patient. Generally, CT with contrast and MRI with contrast take longer than their non-contrast counterparts and are often both performed if your doctor requests imaging with and without contrast. The payoff: your doctor may make a more accurate diagnosis based on the enhanced clarity of the image.

After your scan

You can resume normal activities as soon as your imaging study is over, although you may need to take certain precautions if you received sedation. Drink plenty of water to help the contrast material leave your body. Notify your physician if you experience any rare side effects, such as diarrhea, nausea or vomiting. Seek emergency help for signs of an allergic reaction, including difficulty breathing, itching or hives.


You can feel confident receiving CT scans and MRI scans with contrast at Touchstone Medical Imaging. Our radiologists and technologists complete extensive training that helps them safely administer the right contrast for each study, so they can quickly and accurately deliver results to your doctor, allowing him or her to make your diagnosis.

Touchstone Medical Imaging has locations in Arkansas, Colorado, Florida, Montana, Nebraska, Oklahoma and Texas. If you need an imaging study with contrast, find a Touchstone Medical Imaging center near you.