Frequently Asked Questions

WHO CAN PARTICIPATE IN AN IMAGING STUDY?
Is it safe? Are there any special requirements?

Each study has its own inclusion and exclusion requirements regarding research subjects. These criteria are described in the study advertisement and/or will be explained to you by the investigator or study staff. General requirements for studies using different imaging modalities are described below.

MRI

MRI is safe and comfortable for most people, with only a few exceptions. People who have electrically, magnetically or mechanically activated implants (such as cardiac pacemakers), or those with metal in their body (such as clips on blood vessels in their brain, or other metal fragments) should not have an MRI because the devices may move or not function properly. However, persons with metal dental fillings may have an MRI. Those who suffer from claustrophobia (fear of enclosed spaces) will probably find an MR study uncomfortable. It is recommended that women who are pregnant do not participate in MRI research. Before you are enrolled in an MRI study, the investigator will perform a thorough screening to be sure that MRI is safe for you.

Functional MRI uses the body's own contrast agent, deoxyhemoglobin, to allow visualization of brain activation. Therefore, the technique is non-invasive and requires no radioactivity or injected contrast agents.

The MR scanner is a powerful tube-shaped magnet that uses radio waves to create computerized images of the brain and body. Because the magnet is always on, you will be instructed not to bring any metal objects into the magnet suite, as these objects may become airborne and cause injury. The MR scanner magnet will also erase the magnetic strip on credit cards, so you should leave your wallet outside as well. You will be provided a secure place to store your valuables during an MR study.

Because the MRI study involves imaging procedures that are very sensitive to motion, you may be asked to use a "bite bar" during scanning. A bite bar is a piece of plexiglass covered with sterile dental-impression material. You will make an impression of your teeth in the bite bar, and rest your teeth in this impression for the duration of the study to help immobilize your head.

You will not be able to wear your eyeglasses in the MR scanner. If the study requires that you read or view images and you require vision correction, you should inform the investigator when you sign up for the study and you may be fitted with magnet compatible eyeglasses. It is safe to wear non-colored contact lenses in the MR scanner.

Because MR images may be distorted by metal in the mouth or on the body, you may be asked to leave any removable dental devices such as retainers, removable bridges, or dentures, and body piercings outside the magnet suite.

If you have any questions or concerns about participating in an MRI experiment do not hesitate to ask the study investigators or staff or contact Mary Foley (mtf@nmr.mgh.harvard.edu) at the Martinos Center.

MEG/EEG

There are no known risks associated with MEG/EEG recordings. The MEG procedure consists of sitting in a chair or lying on a bed while your head is positioned in the helmet-shaped bottom of the MEG device that contains magnetic field sensors. These superconducting sensors passively detect weak magnetic fields outside the head produced by brain activity. It is a silent, non-invasive technique and uses neither strong magnetic fields nor radioactivity and injected contrast agents.

People who have electrically, magnetically or mechanically activated implants (such as cardiac pacemakers), or those with metal in their body (such as clips on blood vessels in their brain, steel pins from root canals, or other metal fragments) should not have an MEG/EEG because these devices will (a) cause significant artefacts and disturb the MEG/EEG signal, and (b) possibly cause damage to the sensors which could require expensive service repairs. However, persons with metal dental fillings may have an MEG/EEG.

Because the MEG is always on, you will be instructed not to bring any metal objects into the magnetically shielded room (MSR), as these objects may damage the sensors. In particular, belts, keys, watches, coins, hair barrettes and pins, eyeglasses, and pieces of clothing with magnetic parts should be removed prior to entering the MSR. Also, to prevent any magnetic dust from getting into the MSR, always remove your shoes before entering. Objects such as cell phones, pagers, cameras, flashlights, or any other electrical equipment are strictly forbidden. Never take a bar magnet inside the MSR.

You will not be able to wear your eyeglasses in the MEG. If the study requires that you read or view images and you require vision correction, you should inform the investigator when you sign up for the study, and you may be fitted with non-magnetic eye glasses. It is OK (and in fact preferable) to wear contact lenses in the MEG.

Because MEG signals may be distorted by metal in the mouth, you may be asked to remove such dental devices as tongue rings, retainers, removable bridges, and dentures before entering the MSR. Please inform the study investigator if you wear braces.

If you have any questions or concerns about participating in an MEG/EEG experiment do not hesitate to ask the study investigators or staff, or contact Nao Suzuki (nao@nmr.mgh.harvard.edu) at the Martinos Center.

TMS

Transcranial magnetic stimulation (TMS) is a safe and noninvasive technique for brain stimulation. TMS was invented in 1985 and is now used for clinical and research purposes in thousands of centers worldwide. Currently, the Food and Drug Administration (FDA) has approved TMS applications for the treatment of depression; other clinical applications are being investigated. TMS also has a unique role in understanding how the normal brain works, because it can be used to disengage a brain area for a fraction of a second, allowing scientists to understand its functional role.  

The TMS procedure consists of sitting in a chair or lying on a bed while a TMS coil is placed over your head. The coil sends brief magnetic field pulses that induce weak electric currents in the brain. This coil makes a clicking sound associated with its operation - you will wear ear plugs so the clicks should not be bothersome. You will wear special eyeglass frames that allow us to localize the area of brain stimulation. 

Subjects and patients that consider participating in a TMS study should know that TMS is not suitable for everyone. To see a list of our screening questions, click here. People who have electrically, magnetically, or mechanically activated implants (such as cardiac pacemakers or deep brain stimulation devices) should not have TMS because these devices may malfunction as a result of the TMS pulses. Also, those with metal or magnetic pieces in their head (such as clips on blood vessels in the brain or other metal fragments) should not have TMS because the magnetic pulses may cause the metal to move and/or heat up. However, persons with metal dental fillings may have TMS. It is recommended that women who are pregnant do not participate in TMS research. As an extremely rare adverse effect, even healthy individuals can experience a seizure during TMS. This likelihood is slightly elevated in subjects with epilepsy and some other clinical conditions. However, when TMS has been operated within the National Institutes of Health ( NIH) safety guidelines, there have not been any seizures in healthy subjects. In the unlikely event that a seizure would occur, it would stop immediately because the investigator would stop TMS. All subjects that have experienced a seizure during TMS have recovered fully. A study staff member trained in managing any potential problems will be next to you throughout the experiment to make sure that you are feeling fine. 

You will be required to keep your head still during TMS. After TMS, some subjects have experienced a headache that is apparently related to keeping the head still and/or stimulation of the scalp muscles and nerves. If present, this headache it is typically mild and resolves by itself in a few hours, and if needed, responds well to over-the-counter mild analgesics. The study staff will help you find a comfortable head position to make it less likely that you will experience any headache.  

You will not be able to wear your eyeglasses in TMS. If the study requires that you read or view images and you require vision correction, you should inform the investigator when you sign up for the study, and you may be fitted with special eye glasses. It is OK to wear contact lenses in the TMS, but if you tend to have dry eyes and/or blink a lot, then the provided special glasses may be more comfortable. Generally, if EEG is recorded with TMS, we ask our subjects to blink as little as possible, because blinking disturbs the EEG recordings. 

You will be instructed not to bring any cards with magnetic stripes (such as credit cards) to the TMS room because TMS pulses may deactivate the cards. Because TMS signals may heat up metal in the head area, you may be asked to remove ear rings and necklaces before entering the TMS room. Please inform the study investigator if you wear any metal jewelry. 

If you have any questions or concerns about participating in an TMS experiment do not hesitate to ask the study investigators or staff, or contact Tommi Raij (raij@nmr.mgh.harvard.edu) at the Martinos Center.

Near-Infrared Spectroscopy (NIRS)

NIRS is safe and comfortable for most people. The laser light used to make measurements of your brain has very low power, and for this reason is considered to present minimal risk. In fact, the amount of light to which you will be exposed is considerably less than the amount of sunlight you would feel during an outdoor walk on a sunny day. Furthermore, the technique is noninvasive–in other words, we will not pierce your skin in any way–and does not employ ionizing radiation.

For most NIRS studies, we only recruit subjects between the ages of 18 and 64. This is because we want to study the mature or fully developed brain not yet experiencing the effects of aging past the age of 64. Also, we usually only recruit subjects with no history of neurological trauma or neurological or psychiatric disorders.

If you have any questions or concerns about participating in an NIRS experiment do not hesitate to ask the study investigators or staff.

PET

Human PET imaging studies at the Martinos Center are currently conducted in collaboration with the MGH PET Service. To learn more about participating in a PET study, visit their website at
http://www.massgeneralimaging.org/Pet_Site/NewFiles/WhatIsPet.html

HOW TO PREPARE FOR AN IMAGING STUDY

MRI

If you have gone through the MRI Screening procedure with the study representative, and they have determined that it is safe for you to have an MRI, preparation is simple:

You may eat and drink, sleep and behave as you normally would before your MRI study, unless instructed otherwise by the study representative.

Follow these guidelines:

• Do not wear clothing with metal components (the zippers and buttons on your pants are not a problem, but you will be asked to remove clothing such as metal buttons, belt buckles, shoes with metal shanks, underwire bras, etc.)
• If you have contact lenses, wear these instead of glasses (do not wear colored contacts, tinted ones are OK)
• Remove body piercing and other jewelry (including watches, hair holders, etc.) if possible.
• You may be asked to remove dentures or removable dental bridges, retainers, etc.
• If you have tatoos that may contain metal dye, notify the study representative.
• Do not wear eyeshadow or other makeup that may contain metal specks.

If you will be late for or need to cancel your study appointment, and cannot reach your study representative, call 617-726-5700 and leave a message with the Imaging Center reception staff.

Parking at the Martinos Center will generally cost $5-10. Bring cash, as many study stipends are in the form of a check that will be mailed to you.

MEG

If you have gone through the MEG screening procedure with the study representatives, and they have determined that you are able to have an MEG/EEG recording, preparation is simple:

You may eat and drink, sleep and behave as you normally would before your MEG study, unless instructed otherwise by the study representative.

Follow these guidelines:

• All subjects will be asked to wear pants provided by the hospital (tops can be provided as well), but wearing tops without metal components is appreciated. You will be asked to remove additional clothing items such as metal buttons, belts, shoes, bras, etc.
• If you have contact lenses, wear these instead of glasses
• Remove body piercing and other jewelry (including watches, hair holders, etc.).
• You may be asked to remove dentures or removable dental bridges, retainers, etc.
• If you have tatoos that may contain metal dye, notify the study representative.
• Do not wear makeup that may contain metal specks.
• Because the paste used to apply electrodes can be quite sticky, you may need to wash your face and/or hair afterward. Soap and shampoo are provided, but feel free to bring any additional products you may require.

If you will be late for or need to cancel your study appointment, and cannot reach your study representative, call the MEG lab at 726-8517 and leave a voice mail message.

Parking at the Martinos Center will generally cost $5-10. Bring cash, as many study stipends are in the form of a check that will be mailed to you.

Near-Infrared Spectroscopy (NIRS)

There are no specific preparations for participating in a NIRS study–prior to the study, you may eat and drink, sleep and behave as you normally would. However, you should dress comfortably, in loose-fitting clothes, since we will ask you to either sit or lie still for periods of up to 2 hours.

If you will be late for or need to cancel your study appointment, and cannot reach your study representative, call 617-726-5700 and leave a message with the Imaging Center reception staff.

Parking at the Martinos Center will generally cost $5-10. Bring cash, as many study stipends are in the form of a check that will be mailed to you.

PET

Human PET imaging studies at the Martinos Center are currently conducted in collaboration with the MGH PET Service. To learn more about how to prepare for a PET exam, visit their website at http://www.massgeneralimaging.org/Pet_Site/NewFiles/Prep.html2.

IS MY BRAIN NORMAL?

If you will be participating in a brain imaging experiment involving MRI (or other brain imaging techniques), it is important for you to know that the type of imaging data that will be acquired during the study are not equivalent to those that a doctor would collect to diagnose an illness. In addition, most investigators conducting these studies are cognitive scientists, neurologists, psychiatrists, and physicists, and are not trained in clinical neuroradiology. Therefore, we will be unable to supply you with any medical information about your brain following a research study.

If for any reason, the investigator suspects that there may be a clinical question regarding your scan, appropriate images will be acquired and reviewed with a neuroradiologist. If a follow-up medical exam is advised, you will be referred to an appropriate physician.

For certain studies (especially those involving clinical populations, MGH patients, or others for whom the likelihood of discovering abnormalities is high), arrangements be made by the Principal Investigator to collect images appropriate for clinical diagnosis, and have these images read by a trained neuroradiologist. You may ask the study investigator if such arrangements have been made for the study in which you will participate.

Generally speaking, an imaging research study is not equivalent to a clinical diagnostic work-up.