Adolescent Brain Development and the Effects of Drug Abuse: MRI Information


Information Regarding Magnetic Resonance Imaging (MRI)

In our study, Adolescent Brain Development and Effects of Drug Abuse , we use MRI scans to take pictures of the brain and to quantify different types of brain tissue. Some of the types of brain tissue that we are interested in include fluid volumes, gray matter (the nerve cells), and white matter (the connections between cells).


What is MRI?

MRI stands for Magnetic Resonance Imaging, which is a very safe, noninvasive medical imaging procedure that has been performed millions of times to date. MRI is different from X-ray, computerized tomography (CT), and positron emissions tomography (PET) because it does not use ionizing radiation to take pictures of the body. Instead, MRI uses a strong magnetic field and radio frequencies (RF), similar to the radio frequencies used by your cordless/cell phone, car radio and garage door opener. The images from MRI scans are much more detailed than what can be obtained from traditional X-rays or CT scans. Please click here for a picture of our scanner.

What happens during an MRI?

When a research participant comes for an MRI scan, the first thing that happens is that a trained examiner/technician acquaints the participant with the machine and the overall procedure. The machine has a few major parts:

  1. Table -This is a specially designed table for the participant to lie on. After the participant is comfortable (we have numerous pads, pillows and blankets available), the table slides into the MRI machine, which has a round opening that encloses the table.
  2. Head Coil -This is the part of the machine that actually takes the pictures. It looks like a basket and is placed at the end of the table closest to the machine. The head coil slides over the participant's head and remains there for the entire MRI scan.
  3. Headphones & Earplugs -The MRI scan is very loud. To protect the participant's hearing, earplugs and headphones are provided. There is also a microphone inside of the MRI ‘tube'. The examiner can communicate with the participant via this microphone/headphone system. A system of mirrors allows the participant to see the examiner through a window in the control room.

After the participant has been properly acquainted with the machine, a few key things are explained:

  1. The scan is very loud. The earplugs alone should be enough to dampen the sound to a comfortable level. Via the headphones, the participant can also listen to a CD or music from a radio station, which helps take the focus off of the noisy machine. Some of the noises from the scanner have been described as hammering, knocking, an alarm-like sound, and a sound similar to a fog horn.
  2. The participant must remain very still during the scan. If the participant moves while the machine is taking pictures (making noise), the images will turn out blurry and may not be usable.
  3. A participant will not feel or see anything during their MRI scan. There are no moving parts, lights or laser beams during the scan. Some of the scans may vibrate the table/head coil slightly.
  4. Participants hold onto a call button that they can push if they have any concerns or unexpected discomfort during the scan. This call button provides an immediate signal to the examiner to stop the scan.

How long does an MRI scan take?

Depending on the purpose, an MRI scan can take anywhere from 10 minutes to over 2 hours. Our scanning protocol takes about 45 minutes and is divided up into separate blocks of scans. The machine will run for roughly 5 minutes at time, and will then stop. During the stopping periods, we communicate with the participant using the microphone system. We then tell the participant how long the next scanning block will take. This continues for the entire 45 minutes.

Is MRI safe?

MRI is a very safe procedure for the majority of research participants, however the examiner must take proper precautions to thoroughly screen each participant. Individuals with metal in their body may not be safe to have an MRI scan. Examples of metal implants include cardiac pacemakers, defibrillators, other electronic medical devices, aneurism clips, metal rods, pins, staples, screws, etc. Some types of permanent inks such as those used in tattoos or permanent make-up might also be unsafe. We can safely scan people who have permanent retainers on their teeth, but we prefer not to scan people with full braces, because the images are distorted. In addition, we will not scan anyone who is pregnant or who might be pregnant. Before we scan any participant, we ask many questions about the participant's medical history. It is important for the participant (or his/her parent) to disclose any medical operations/procedures they have undergone, so the examiner is able to properly evaluate their safety. Individuals who are claustrophobic (afraid of small spaces) may also have problems with an MRI scan because the ‘tube' of the machine is relatively small.

In addition to these safety precautions, the room that houses the machine is kept free of metal objects. Anyone who enters the room must empty his/her pockets of anything that has metal in it. People are also screened for jewelry or other types of apparel/clothing that might have metal pieces.

Together, these precautions assure that the MRI will be a safe procedure.

What shouldn't I wear for my MRI?


  1. Transdermal patches. (Nicotine, birth control, or other medicated patches)
  2. Jewlery. (Watches, piercings (unless they are plastic), rings, necklaces, etc. These things can be removed when you arrive at the MRI center).
  3. Belts. (again, they can be removed at the MRI center).
  4. Underwire bras.
  5. Pants or bibs with large metal buckles.
  6. Jackets/Sweatshirts with long/large metal zippers.
  7. Hair pins, bungee's with metal clips, etc.; many fabric-covered hair binders have metal threading underneath the fabric
  8. Shoes (these can be removed just prior to the scanning session).
  9. Nail polish or other make-up with glitter embedded into it
  10. Try to keep hair products (gels, mousse, sprays) at a minimum

If you are unable to meet these guidelines the day of your appointment, it is likely we will be able to provide you with scrubs to wear for the scan.

We will provide you with a secure locker for any belongings that are not allowed to accompany you to the MRI machine (for example watches, wallets, purses, coins, cell phones, pagers, other electronic devices, credit cards/cards with magnetic strips, etc.).

What should I wear for my MRI?

  1. T-shirts, sweat shirts, sweat pants
  2. Jeans with normal sized zippers/buttons.
  3. Anything comfortable without metal is preferred.
  4. Sometimes the scanning room is at a cool temperature, so please wear something warm.

After the MRI scan.

When the MRI scan is completed, the table will be removed from the machine, and the participant can immediately leave. We do not provide you with pictures of your scans, but we can show you a few images on our computer screen if you would like to see them.

The rest of our data processing is done after the scan and combines the data from many participants.

Other questions?

If you have other questions about the procedure, please call our laboratory (612-624-4054).


Please click here for a picture of our scanner.



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