What is Magnetic Resonance Imaging?


Magnetic resonance imaging, or MRI, is an imaging method used in radiology to create a visualization of internal structures of the body. MRI uses nuclear magnetic resonance, or NMR, to create an image of the nuclei of atoms.


Preparing for an MRI

The MRI will create a very strong magnetic field that will pull any magnetic metal on or in the body. Always remove metal items, including credit cards, before you enter the scanner. Metal can also cause the MRI image to degrade. Surgical staples and hardware typically pose no risk as long as they have been in place for at least 4 weeks. An x-ray may be necessary to check for the presence of any metal in your body or head before receiving an MRI.

It’s also a good idea to skip any make-up or sprays as some contain metallic dust that can negatively affect the imaging.

Before receiving an MRI, you will fill out a questionnaire. You may continue any medication your doctor has prescribed, unless the technician has informed you otherwise. You can also eat normally, unless a contrast injection will be necessary for the procedure.

Finally, an MRI test requires being in a confined space for an extended amount of time. If you have claustrophobia, you may require sedation. Be sure to inform your doctor when you set up your appointment.


During an MRI Test

During the test you will lay on a padded table that moves into an open magnet that creates a strong magnetic field around your body. Remain relaxed during the scan and do not move, as this will cause blurry images. You will hear thumping and humming noises, along with the occasional knock. These noises are normal and occur as the magnetic field changes. You will be able to speak with the technician and see the control room during the procedure so there is no need to panic. Your doctor may also order something known as an image enhancement agent, which is a fluid injected into your arm. This agent is used only to make the image more clear as it develops and is no cause for alarm. Most MRI tests take anywhere from 30 to 45 minutes.


Are MRIs Safe?

An MRI test is safe for most patients, although some may not handle an MRI well. Individuals with medical devices implanted in the brain, heart or ear, or those with metal near an important organ, should not be scanned in an MRI machine. Individuals who suffer from claustrophobia may also have difficulty with this test.


Advantages of an MRI Scan

MRI scans are an excellent way to view soft tissues of the body, particularly the spinal cord, brain and nerves that cannot be seen clearly with an x-ray or CAT scan. Ligaments, tendons and muscles are also clearly displayed on an MRI to examine the shoulders and knees after an injury. While MRIs are more expensive than CAT scans and x-rays, they are an important diagnostic tool and do not use radiation.



  • Soft-tissue structures like the ACL, ligaments and lumbar discs are clear and detailed
  • MRIs assist doctors in evaluating organ function
  • The detail of an MRI is an important tool for diagnosing and evaluating tumors early
  • MRI contrast agents are unlikely to cause allergic reactions
  • MRIs can detect abnormalities that may otherwise by obscured using other methods
  • An MRI is a non-invasive alternative to an x-ray angiography to diagnosis issues with the spine or knees
  • There is no exposure to radiation



  • Unknown metal implants may be seriously affected by the strong magnetic field produced by the MRI machine
  • MRI scans should always be avoided during the first 12 weeks of pregnancy unless there is a very strong reason to use an MRI over an ultrasound.


When do I Receive the Results?

The radiologist will check the images during our scan, but this is only done to make sure they are clear enough for evaluation. The images will then be sent to Dr. Kevin Yip, who will then contact you to discuss the results.