MRI (Magnetic Resonance Imaging)

Author: Courtney Misher, MPH, BS R.T.(T)
Last Reviewed: August 02, 2022

Picture of an MRI machine

MRI stands for “magnetic resonance imaging” scan. It is a medical test that lets your healthcare provider see detailed images of your internal organs using a large magnet, radio waves, and advanced computer software.

Why would I need an MRI?

MRI scans are used because they give special details that cannot be seen in other radiology tests. MRI scans can help diagnose or look at the size of tumors, see if the tumor can be removed with surgery, and help create the best plan for radiation treatments.

MRI scans used for cancer-related imaging are most often for:

  • Brain and spinal cord tumors.
  • Head and neck tumors near the base of the skull.
  • Tumors in the chest, particularly near the chest wall or heart.
  • Breast cancer patients may have an MRI to check for breast cancer in the other breast.
  • MRI may be used with a mammogram in women who have dense breast tissue or are at high risk for cancer.
  • Liver cancer.
  • Prostate cancer.

MRI scans are most often used for non-emergent imaging tests. This is because MRI scans take longer to be done and read.

How do I prepare for an MRI scan?

Eat normally and take your medication unless your provider tells you differently. Metal can affect your test so you will be asked questions about any metal that could be inside you like a port, joint replacement parts, internal implants, etc. Before your MRI, you will be asked to remove any items that may affect the scan such as jewelry, glasses, wigs, dentures, hearing aids, and bras with underwire.

How is this test performed?

You will lie flat on a table that moves through a large tube (this is the magnet). The tube can be loud while it is on, and you may be given earplugs to protect your ears. The test can take anywhere from 30 minutes to 2 hours, depending on what areas are being scanned. A radiology technologist will be in a nearby room with a window and microphone to hear and talk to you during the test. You should try to hold still during the test because movement can cause blurry images.

IV contrast may be used during the MRI to see the blood vessels better. This contrast is known as “gadolinium” and is different from the contrast used during a CT scan. If you have an allergy to CT contrast, which is iodine based, there is a good chance you will still be able to have the MRI contrast. Gadolinium cannot be given to anyone with kidney disease because it can harm the kidneys.

How do I manage an MRI scan if I am anxious or claustrophobic?

Many people worry about being in a tube during the exam. However, larger tubes, or bores, are being used making them easier to manage. If you are claustrophobic (afraid of small or confined spaces) your provider may be able to give you medicine to help you relax. You will need to have a ride home after the exam if you have taken medication to relax since you will not be able to drive.

If you are not able to tolerate the MRI after taking medication an open MRI scan may be an option for you. Open MRI scanners are not as widely available as standard MRI scanners. The quality of the pictures from an open MRI may not be as good so you should talk with your provider about if this is an option for you.

How do I receive the results of your MRI?

A radiologist, who is a doctor that specializes in looking at different types of images, looks at the scan and creates a report. The report provides detailed information about normal and abnormal findings. Your provider will be able to discuss your results with you.

If your MRI scan is for radiation planning purposes only, then your radiation oncologist will use the images to create your radiation treatment plan.

MRI for cancer. American Cancer Society. (n.d.). Retrieved August 1, 2022, from

U.S. Department of Health and Human Services. (n.d.). Magnetic Resonance Imaging (MRI). National Institute of Biomedical Imaging and Bioengineering. Retrieved August 1, 2022, from

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