MRI is a form of imaging that provides a non-invasive method of looking at structures inside the body. MRI uses a very strong constant magnetic field, weaker variable-strength magnetic fields, and radio frequency (RF) pulses. The RF pulses are similar to those transmitted by radio stations.

MRI scanners interact with atoms in the body. Hydrogen atoms are most commonly used since our bodies contain a large amount of water and, therefore, hydrogen. The hydrogen atoms in your body normally spin in random directions, but most of them align and spin in the same direction when they are in the strong magnetic field inside the scanner.  A computer manipulates the magnetic field and sends radio waves of certain frequencies at precise moments to cause the hydrogen atoms to produce an echo.  Bone, blood, muscle, fat, fluid, etc., each emit unique signals which are read and processed by a computer to produce very accurate images of the body part being scanned.  The MRI scanners at the Sammons BrainHealth Imaging Center are specially calibrated for human brain research.

Yes, MRI is considered a safe form of imaging because it is non-invasive, and there are no known lasting biological effects from the magnetic fields or RF energy used.  Some temporary discomfort may be experienced such as dizziness, a metallic taste in the mouth or warmth during the scanning process.  MRI does not use ionizing radiation, so it does not share the biological risks of x-ray radiation used for x-ray films or Computed Tomography (CT/CAT) scans.  The chief safety concern with MRI involves most ferromagnetic (containing iron) items and electronic devices entering the strong magnetic field.  

People entering an MRI room should not wear or have on them anything electronic or containing iron. Certain items may be acceptable, but we must know what they are to determine their safety status.  When you arrive for your MRI scan, we perform a comprehensive safety screening.  This includes completing a questionnaire where you list any implanted items, devices or foreign bodies that you may have.  A trained MRI professional will review this information with you.  Please bring any implant identification cards with you and note that certain items considered safe in some MRI scanners may not be safe in others.

Functional magnetic resonance imaging (fMRI) is a method of imaging that evaluates the brain’s activation response to types of physical sensation (sight, sound, touch, taste, smell) or cognitive activity such as problem solving.  The areas of the brain that are responsible for processing the incoming information recruit more oxygen-rich blood.  An fMRI captures an image of the brain at a specific time that the sensation or activity is presented, revealing if there is more oxygenated blood in one part of the brain compared to others.  This image is usually referred to as blood oxygenation level-dependent response (BOLD).

The magnetic field of MRI scanners is typically expressed in units of tesla (T).  The MRI scanners at the Sammons BrainHealth Imaging Center have field strengths of 3-tesla.  For reference, this is about 60,000 stronger than the earth’s natural magnetic field; 3T is also about three times stronger than the electromagnets used to lift automobiles.  The Sammons BrainHealth Imaging Center features two Siemens Prisma MRI scanners.  This state-of-the-art equipment is preferred by top brain scientists because it is specifically optimized for the acquisition and interpretation of rich research data about the brain’s structure and function.

Before entering the MRI room, you will need to remove your personal belongings – including hearing aids, hair accessories (ex: wigs, extensions), jewelry, cell phones, credit cards, etc.  Lockers are provided for your belongings.  The process will be explained, and any questions you have will be answered.  

You will be provided with a call button to alert the scanner operator of any concerns that might come up during your scan, and there is an intercom to allow for communication.  You will be monitored throughout your scan by the scanner operator.

Each study may have different tasks and procedures that will affect the length of time spent in the scanner, although scans generally last less than an hour.  When you enroll in a study with an MRI component, the requirements will be specifically reviewed with you in detail.

Many medical implants are acceptable for MRI scanning.  Orthopedic hardware such as joint replacements, plates, nails and screws are typically safe.  Individuals with implanted cardiac pacemakers, ICDs (defibrillators), stimulators, pumps, and other electronic devices will not be able to have MRI scans at the Sammons BrainHealth Imaging Center, even if the device is classified as “MR-Conditional.”  Restrictions still apply if a device is present but not active. 

When you arrive for your MRI scan, we perform a comprehensive safety screening. This includes completing a questionnaire where you list any implanted items, devices or foreign bodies that you may have.  A trained MRI professional will review this information with you.  Please bring any implant identification cards with you and note that certain items considered safe in some MRI scanners may not be safe in others.