MRI and MR Angiography

MRI is shorthand for magnetic resonance imaging, a radiation-free procedure used to visualize various parts of the body in great detail. It uses strong magnets, usually electromagnets, to create alternating pulses of magnetization through the body to to differentiate between different tissue types. An MRI scan helps us diagnose diseases and damage from injuries caused by events such as auto accidents and sports participation. We read MRI scans of the brain, vascular system, bones and joints. An MRI scan also allows us to check the health of the breasts (breast MRI) and ovaries in women, the prostate in men, and the liver, kidneys, gallbladder and pancreas. MR angiography is a subset of MRI in which studies are customized to evaluate the blood vessels.

There are two types of MRI machines: closed MRI and open MRI. Open MRI was developed to provide greater comfort for claustrophobic patients or obese patients who do not fit comfortably inside the closed MRI tunnel. Unlike standard MRI, open MRI is not enclosed along the sides.

MRI scans are sometimes performed with intravenous contrast. The contrast used for MRI is different from that used for CT or x-rays. It is based on a compound called gadolinium and has different properties. Patients allergic to CT/x-ray contrast can usually safely receive MRI contrast, but please inform your technologist of any allergies before your examination.

Preparing for an MRI

Most of the preparation for the MRI is to ensure safety because MRI is performed using a very powerful magnet to obtain images. Please bear with us and the technologist as we take lengthy precautions to ensure that no one is ever injured or harmed in any way by the MRI machine.

The facility where an MRI is performed will have specific instructions regarding safety. In general, this includes a detailed checklist to ensure a patient does not have any conditions or implants which would make MRI unsafe. The technologists perform detailed, extensive screening for anyone who enters certain areas near an MRI machine to ensure safety of the patient, staff, and others. In some situations it can be extremely dangerous to be near an MRI machine whether it is in use or not, especially in people with metal in their bodies. The magnet attracts metal which can result in very strong forces pulling on metallic objects, and the magnetic field can induce electrical currents or heating in some devices. Examples of potentially problematic materials include:

  • Aneurysm clips
  • Body piercings
  • Clothing with metallic fibers or metallic components
  • Cochlear implants
  • Coils, stents, and other procedure related implants
  • Dental hardware
  • Heart valves (artificial)
  • Jewelry
  • Medication pumps
  • Metal fragments (bullet, shrapnel, etc.)
  • Nerve stimulators
  • Pacemakers, defibrillators, and other monitoring devices
  • Orthopedic pins or screws

Any metallic jewelry must be removed prior to entering the MRI area. Other devices should be removed if not possible. For implanted or embedded devices that cannot be removed, you will need to provide documentation that the device is MRI safe or MRI compatible to ensure the safety parameters fall within the particular MRI machine’s parameters. Other metal or potential metal in the body may require additional screening with an x-ray or CT scan, which will be explained by the technologist.

A blood test may be necessary if your study includes receiving IV contrast, as patients with severe kidney injury or kidney failure are at risk of a rare but very serious condition called nephrogenic systemic fibrosis if they receive gadolinium based contrast. The contrast absolutely cannot be given to patients who are on dialysis. A questionnaire will also be given to you to ensure you have no other medical conditions or allergies that might be an issue when receiving contrast, or to check if you are taking any medications which may cause complications.

What should I expect when undergoing an MRI?

The MRI machine is housed in a special room with proper shielding and equipment safe to be near the strong magnet. You will lie down on a table that moves in and out of the machine, possibly with the body part of interest extended. Breast MRI is performed with the patient lying face down. A device called a coil will be placed around the body part of interest, such as the head, abdomen, or knee. The table will then slide into the scanner.

Conventional MRI scanners are a long tube that is enclosed along the sides but open at the ends. An Open MRI is made up of two flat plates so that the sides remain open as well. This is better for claustrophobic patients as the space is not fully enclosed. As the scanner obtains images, you will hear some loud sounds which may sound like beeping, knocking, or clicking. Your technologist may be able to provide headphones to reduce the noise and provide a way to give instructions. 

MRI scans take longer to perform and are more sensitive to motion than CT or x-rays. Your technologist may ask you to hold your breath at times for several seconds at a time, or to refrain from swallowing or talking at certain points. This is to ensure that the best quality images are acquired. Sometimes it may be necessary to repeat imaging if there is too much motion.

If receiving contrast, the technologist will pause the procedure midway to administer contrast, then resume imaging.

While most MRI scans take less than 30 minutes to obtain, some types of scans (particularly multiple scans of different body parts) may take longer. Your technologist should be able to tell you about how long the scan will take, and give updates during the examination.

After the scan, you should have no residual effects of the scan. The images are processed by the computer then sent to the radiologist for interpretation.

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To learn more or for any questions, please call (714) 970-0200 or email office@fullertonradiology.org. For facility specific questions or concerns, please use the Locations page to find the appropriate contact information. Fullerton Radiology Medical Group radiologist physicians help doctors and patients at its affiliated locations, which serve the Anaheim, Bellflower, Brea, Buena Park, Cerritos, Corona, Fullerton, Orange, Placentia, Riverside, Yorba Linda, and neighboring communities.