FAQ

MRI with or without contrast

Magnetic resonance imaging (or MRI) is a non-invasive medical imaging technique that uses powerful magnetic fields and radio waves to take high-quality pictures of your organs and body.

MRI scanners are large magnets that create strong magnetic fields around the part of the body being imaged. The magnetic field made by an MRI scan is used to create a detailed image of the inside of your body that doctors can use to assess and diagnose your condition. In contrast to X-ray machines or computed tomography (CT scan) machines, MRIs do not use X-rays or ionizing radiation.

MRI scans can be used to gather data on many areas of the body. The MRI allows your doctor to see organs, bones, and tissues in your body without surgery. This can help doctors diagnose a disease or injury.

Some conditions an MRI scan may help detect include:

  • Brain injury
  • Cancer
  • Signs of a stroke
  • Heart Disease
  • Spinal disk problems
  • Bone and joint injuries
  • Internal organ health
  • Soft tissue inflammation

MRI is more capable of assessing bone marrow and soft tissue than X-rays or CT scans. Connect with a doctor on Sesame to see if you may need an MRI scan.

An MRI does not use radiation, so there is no risk of exposure to radiation during the MRI process. The MRI machine is a large magnet, and cannot be used on patients with:


  • Pacemakers
  • Aneurysm clips
  • Some prosthetic devices (like some dental or eye prosthetics)
  • Implanted heart defibrillators
  • Neurostimulators
  • Cochlear implants
  • Intrauterine devices

MRI can also pose risk to patients who may have metallic objects in their body (such as shrapnel, mesh, plates, or sutures). Be sure to discuss this with your doctor before your appointment if this applies to you.

Notify your physician before an MRI scan if you are pregnant or think you may be pregnant. There are no proven risks to pregnancy or pregnant women from MRI scans after the first trimester of pregnancy. However, the contrast material gadolinium is not usually used on patients who are pregnant, due to the risk of possible fetal effects from the water-soluble contrast dye.

Some patients experience claustrophobia or anxiety in a closed MRI machine and should be advised accordingly. Certain models of MRI machines are equipped with images to help ease anxiety and/or claustrophobia.

Contrasting agents may be used in an MRI procedure, and have been known to cause allergic reactions. Contrast dyes are safe and do not cause internal discoloration. Allergic reactions are rare, and radiology departments are equipped to treat them if needed. Before your scan you should tell your doctor about:

  • Any food, dye, preservative, or drug allergies
  • Medications you are taking, including herbal supplements
  • Recent illness
  • Any medical history of heart disease, asthma, diabetes, or hayfever

If you have liver or kidney problems, consult with your doctor before scheduling an MRI with contrast.

An MRI with contrast is an MRI that includes the use of contrast (sometimes called a "dye"), given orally or intravenously to a patient prior to the MRI. Adding contrast, also called gadolinium contrast, helps radiologists and doctors better interpret your imaging and is often used to enhance the visibility of blood vessels, tumors, inflammation, or certain organs.

Contrast agents are dyes used to help the clarity of scanned images. They are usually swallowed, or injected into a vein.

The most common contrast agents used by radiologists are:

  • Iodine
  • Gadolinium
  • Barium-sulfate materials

These dyes are safe but have been known to cause mild allergic reactions in some cases. Severe reactions are rare.

Tell your doctor in advance about the following:

  • Any food, dye, preservative, or drug allergies
  • Medications you are taking, including herbal supplement
  • Recent illness
  • Any medical history of heart disease, asthma, diabetes, or hayfever
  • History of kidney and liver problems or disease

Contrast is a dye taken orally or administered intravenously that may be recommended for several reasons, often to enhance the clarity of the imaging.

You should check with your referring physician if you don't know which MRI to book.

Before an MRI scan, a patient may be able to eat and drink normally, while taking their usual medication, unless advised otherwise. In certain cases, you may be asked not to drink water for up to four hours before the scan; in other cases, you may be asked to hydrate before receiving the contrast agent. These conditions depend on the area of the body being scanned, and the reason for scanning.

During your MRI, you may be asked to disrobe and change into a hospital gown before your scan.

Additionally, you may be asked to remove any metal objects that might interfere with the MRI scan such as:

  • Earrings
  • Bracelets
  • Necklaces
  • Rings
  • Eyeglasses
  • Watches
  • Dentures
  • Wigs (as some wigs contain traces of metal)
  • Body piercings
  • Hearing aids
  • Underwire bras

An MRI scanner is operated by a radiologic technologist and is used for the imaging of a certain part of the body. You can speak to your technologist during the procedure via a microphone in the machine. If you have a history of claustrophobia, you may be given a sedative drug to relieve anxiety during the procedure.

Once you are in the MRI machine, a strong magnetic field is created around you or the part of the body being scanned. The procedure is completely painless. The protons in your body, or the specific area of your body, will line up in a single direction. Short bursts of radio waves will be directed at your body, or a specific area of your body, that will cause these protons to emit radio signals. These signals are then combined like pixels on a computer screen to create detailed imaging of tissue, bone, and organs inside your body.

In some cases, a contrasting agent may be injected through your veins to enhance visual details in your scan. Gadolinium is the most frequently used contrast agent for MRI scans. Side effects of gadolinium are mild but may produce a chilling effect at the injection site or a “pins and needles” feeling. Sesame offers MRI procedures with and without contrast.

The scan can last anywhere from 15 to 90 minutes, depending on the area of the body being examined, and how many images must be collected. The internal part of the magnet produces noise that can be blocked out with earplugs or music played during the procedure. Connect with doctors on Sesame to determine the MRI procedure that works best for you.

MRI services are completely painless and non-invasive. If you haven't been sedated, you can resume your usual activities immediately after the MRI.

Functional magnetic resonance imaging (fMRI) measures blood flow during brain activity. An fMRI produces images that detail the areas of the brain that are being used for certain functions to evaluate the effects of brain disease or assess damage from injury. An fMRI can detect abnormalities in the brain that other imaging procedures cannot catch.

Like an MRI scan, a functional MRI scan uses powerful magnets to produce a clear image. An fMRI may help in diagnosing such ailments as Alzheimer's disease, multiple sclerosis, epilepsy, brain tumors, and chronic pain. They can also help provide insights into lingering effects from a stroke or brain trauma.

Many radiology and imaging centers now have wide-bore/open MRI machines, which are beneficial not only to patients who may suffer from claustrophobia but also for patients who cannot fit into conventional MRI machines.

If you are claustrophobic (have a fear of enclosed spaces), you might be given a drug to help you feel less anxious and possibly a little drowsy. Most people get through the exam without any difficulty.

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