MRI With and Without Contrast

Sometimes Dr. Grunch orders an MRI “with and without contrast.” That means the scan is done twice in one visit: once on its own, and again after a contrast dye is given through an IV. Comparing the two sets of pictures shows things a regular MRI can miss.

The contrast used for MRI is called gadolinium. It is not the same as the iodine dye used for CT scans. After the first set of pictures, a small amount is given through an IV in your arm or hand, and the scan is repeated.

Gadolinium travels through the bloodstream and collects in areas where blood flow is increased or the normal barriers in the tissue are broken down, such as tumors, infection, inflammation and scar tissue. Those areas “light up” on the second set of pictures.

Contrast is especially helpful for:

• Tumors of the brain, spine and nerves, such as gliomas, meningiomas, schwannomas and cancer that has spread to the spine
• Infection, such as discitis, spinal osteomyelitis, an epidural abscess or a brain abscess
• After spine surgery, to tell the difference between scar tissue and a new or leftover disc herniation
• Inflammation of the spinal cord or nerves, such as transverse myelitis

Most MRIs for routine neck and back pain do not need contrast. Dr. Grunch adds it when she needs to look for one of these problems or when you have had spine surgery before.

• Follow all the steps for a regular MRI, including telling the center about implants and leaving metal at home.
• Tell the imaging center if you have kidney disease, are on dialysis, or have had a kidney transplant. You may need a blood test to check kidney function first.
• Tell them about any prior reaction to MRI contrast. A reaction to CT (iodine) dye does not usually mean you will react to gadolinium, but they still need to know.
• Let them know if you are pregnant or breastfeeding.
• You can usually eat, drink and take your medicines as normal. Some centers ask you not to eat for a few hours before, so follow their instructions.

The first part of the scan is the same as a regular MRI. Then the technologist slides you partway out, gives the contrast through the IV over a few seconds, and repeats the pictures. Some people feel a brief cool sensation in the arm. The whole visit usually takes 45 minutes to an hour.

The IV is removed and you can go back to your normal day. Drink extra water for the rest of the day to help your kidneys clear the contrast, unless you have been told to limit fluids. A radiologist reads the images, and Dr. Grunch or one of her physician assistants will go over them with you at your visit.

Gadolinium is very safe for most people. Mild side effects such as headache, nausea or a cool feeling at the IV site are uncommon and short-lived. Allergic reactions are rare, and the imaging center is prepared to treat them. People with severe kidney disease need extra caution, which is why the center may check your kidney function first. Small amounts of gadolinium can remain in the body after a scan, and no harmful effects from this have been shown, but it is one reason contrast is used only when it adds useful information.

What does “with and without contrast” mean?

The MRI is done twice in the same visit, first without dye and then after gadolinium contrast is given through an IV. Comparing the two shows areas of tumor, infection, inflammation or scar tissue.

Is MRI contrast the same as CT dye?

No. MRI uses gadolinium, while CT uses iodine-based dye. They are different substances, and an allergy to one does not always mean an allergy to the other.

Why would I need contrast after back surgery?

Contrast helps tell the difference between scar tissue, which lights up, and a disc herniation, which usually does not. That difference can change your treatment.

Do I need kidney blood work before a contrast MRI?

Only some patients do, usually people over a certain age or with kidney disease, diabetes or high blood pressure. The imaging center will tell you if you need it.

If Dr. Grunch has ordered an MRI with contrast for you and you have questions, call 470-293-9800 or contact us. You can also ask general questions any time through our “Ask Us Anything” chat. For questions about scheduling, cost or arrival time for the test itself, call the imaging center where it is booked.

Related: All imaging and diagnostic tests · Discitis · Spinal cord tumors

This information is for educational purposes only and is not medical advice. It does not replace individualized care from a licensed physician. Please talk to your provider about your symptoms and follow the instructions from your imaging center.