About MRI

An MRI machine or scanner uses a powerful magnet and radio waves linked to a computer to create remarkably clear and detailed cross sectional images of the body. To visualize an MRI, think of your body as a loaf of bread with its many slices. The MRI allows the physician to see many different “slices” of a body part by taking pictures from outside the body. The “slices” can be displayed on a video monitor and saved on film or disk for analysis.

For some MRI studies, a contrast agent, usually gadolinium may be used to enhance the visibility of certain tissues. The contrast agent is given via a small intravenous (IV) line placed in a vein in your arm.

Time required:

Typically 30-45 minutes

Why is MRI used?

MRI can be used to view, monitor, or diagnose:

  • spine, joint or muscle problems
  • abdominal tumors and disorders
  • brain tumors and abnormalities
  • breast cancer
  • heart or blood vessel problems

How to prepare For MRI?

Before an MRI, eat normally and take your usual medications unless otherwise instructed. You will be given a hospital gown to wear or instructed to wear loose clothing without metal fasteners. Remove all accessories, such as jewelry or hair pins/clips. Also remove wigs, dentures, glasses, and hearing aids. Metal objects may interfere with the magnetic field during the exam, affecting the quality of the MRI images. The magnetic field may damage electronic items. Tell the technologist (the person performing the MRI) if you have any of the following:

  • prosthetic joints
  • pacemaker, defibrillator, or artificial heart valve
  • implanted venous access device
  • cochlear/inner ear implants
  • spinal stimulator
  • intrauterine device (IUD)
  • metal plates, pins, screws, staples or bullets/shrapnel
  • tattoos or permanent make-up
  • transdermal patch
  • anxiety in confined spaces (claustrophobia)

If you are pregnant or suspect you may be pregnant, tell the technologist.


There are no known harmful effects from exposure to the magnetic field or radio waves used in MRI imaging, although MRI is generally avoided in the first 12 weeks of pregnancy. In such cases, other imaging methods are used unless there is a strong medical reason to use MRI.


The results of your exam will be provided to the physician that referred you to Silicon Valley MRI & CT in approximately 24 hours. We only provide these results directly to your physician so that they can assist you to clearly understand the interpretation provided by our radiologist.