Magnetic Resonance Imaging

[Image: from Chris Rorden made with InkScape]

What is MRI?

Magnetic Resonance Imaging (MRI) is a safe way to see inside the body. It uses a strong magnet and radio signals. MRI works by aligning, flipping and relaxing the hydrogen nuclei (protons) in your body.

  1. The magnet aligns protons: When placed in a strong magnetic field, protons align and begin to spin, in the same way a spinning top aligns against gravity.
  2. After the nuclei are aligned, a radio frequency (RF) pulse flips protons, just as tapping a spinning top causes it to wobble.
  3. Immediately after the RF pulse ends, protons begin to realign with the magnet. During this relaxation they emit a radio signal (the protons are resonating, similar to the ringing sound a bell makes when struck). We can measure this signal with an antenna. Crucially, different tissue types (fat, water, brain cells) relax at different rates, allowing us to distinguish them.

Preparing for your MRI scan

When you arrive, we will review your medical history with you. To expedite this process, you can view, print, and complete the MRI screening forms (4) at home. This is important, as some people can not be scanned (for example, individuals with pace makers). You will also read and sign a consent form. Due to the strength of the magnetic field you must remove all metallic objects before you are scanned (jewelry, glasses, cell phones, hair accessories, credit cards, etc.) You can also watch our informational video to find out more about what to expect during your study.