MRI

what is a mri exam?

Magnetic resonance imaging (MRI) is a medical imaging technique that uses a magnetic field and computer-generated radio waves to create detailed images of the organs and tissues in your body.

Most MRI machines are large, tube-shaped magnets. When you lie inside an MRI machine, the magnetic field temporarily realigns water molecules in your body. Radio waves cause these aligned atoms to produce faint signals, which are used to create cross-sectional MRI images — like slices in a loaf of bread.

The MRI machine can also produce 3D images that can be viewed from different angles.


Why an MRA vs. MRI?

mri

An MRI is a type of scan used to view internal body parts.

This can include the organs, tissues, and bones. The MRI machine creates a magnetic field and then bounces radio waves through the body that work to map the scanned part of the body.

Sometimes during MRIs, the doctor must use contrast agents that help the radiologist to see the body part being scanned more thoroughly.


mra

An MRA is a type of MRI exam.

Usually, the MRA is done in conjunction with the MRI. MRAs evolved from MRIs to give doctors the ability to look at blood vessels more thoroughly.

The MRA is composed of MRI signals that include spatial data.


Both MRAs and MRIs are used to view internal parts of the body.

MRIs are used for brain abnormalities, joint injuries, and various other abnormalities while MRAs can be ordered for:

MRIs and MRAs aren’t very different. The MRA scan is a form of an MRI and is performed with the same machine.

The only difference is that the MRA takes more detailed images of the blood vessels than the organs or tissue surrounding them. Your doctor will recommend one or both depending on their needs to make a proper diagnosis.





what are the risk of having an mri exam?

Because MRI uses powerful magnets, the presence of metal in your body can be a safety hazard if attracted to the magnet. Even if not attracted to the magnet, metal objects can distort the MRI image. Before having an MRI, you'll likely complete a questionnaire that includes whether you have metal or electronic devices in your body.

Unless the device you have is certified as MRI safe, you might not be able to have an MRI. Devices include:

  • Metallic joint prostheses

  • Artificial heart valves

  • An implantable heart defibrillator

  • Implanted drug infusion pumps

  • Implanted nerve stimulators

  • A pacemaker

  • Metal clips

  • Metal pins, screws, plates, stents or surgical staples

  • Cochlear implants

  • A bullet, shrapnel or any other type of metal fragment

  • Intrauterine device

If you have tattoos or permanent makeup, ask your doctor whether they might affect your MRI. Some of the darker inks contain metal.

Before you schedule an MRI, tell your doctor if you think you're pregnant. The effects of magnetic fields on fetuses aren't well understood. Your doctor might recommend an alternative exam or postponing the MRI. Also tell your doctor if you're breast-feeding, especially if you're to receive contrast material during the procedure.


During an MRI scan


Once in the scanner, the MRI technician will communicate with the patient via the intercom to make sure that they are comfortable. They will not start the scan until the patient is ready.


During the scan, it is vital to stay still. Any movement will disrupt the images, much like a camera trying to take a picture of a moving object. Loud clanging noises will come from the scanner. This is perfectly normal. Depending on the images, at times it may be necessary for the person to hold their breath.


If the patient feels uncomfortable during the procedure, they can speak to the MRI technician via the intercom and request that the scan be stopped.