Planning and Executing The Study

Initial Considerations

Approval

fMRI studies performed at the Montreal Neurological Institute (MNI) have to be approved by the MNI MR Research Committee and the MNI Research Ethics Board. Please ensure that you have obtained this approval, as well as the required forms and documentation, before arriving at the BIC.

Stimulation and Feedback

You will need to decide how you are going to present stimuli or prompts to your subjects in the MR scanner, as well as how to record any feedback that you are interested in. Some equipment is in place for this purpose, but specialized needs are the responsibility of the experimenter.

The LCD projectors used to show visual stimuli to the subject operates in 1024 x 768 resolution and below. If you are going to use the head coil for the experiment, keep in mind that in most cases, it is not possible to see the entire screen area with the current coil and display setup without reducing the zoom setting on the projector's lens . You should try out the display and take this into account when setting up the experiment. The following image roughly represents the subject's field of view when using the mirror assembly with the head coil and a reasonably large zoom setting.

Task Design

During MR scans, subject motion must be kept to an absolute minimum, and because of the strict immobilization requirements, subjects generally cannot tolerate scanning sessions which last longer than about 1.5 hours. Please consider your subject's comfort and tolerance levels when designing experimental paradigms.

Another extremely critical aspect of your fMRI task design is the inclusion of a baseline task within each functional run. Your test conditions will need an appropriate control task so that you can obtain a contrast of BOLD activation. This applies to both event-related and blocked experimental designs. This is an important concept to keep in mind, and if you have any questions about your task design, feel free to contact us for advice BEFORE you begin your scanning sessions.

Booking Scanner Time

Scanner time on the Siemens Sonata and Tim Trio systems can be booked online at the McConnell BIC Scheduling website http://mni-bic.mcgill.ca/

Please check the online schedule for available time slots. And make sure you book enough time to carry out all the experiments you are planning, including setup time and possible delays between scanning runs. Also, make sure that you have a consent or MR questionnaire form and a requisition form for each subject, filled in and signed before you arrive at the scanner. If you do not yet have your own, you may pick up a BIC MR consent form at the reception desk located on Webster 3B. The requisition form is e-mailed to you in pdf format once your submitted requisition is approved and entered on the schedule:

Safety Issues

There are a number of safety issues to keep in mind during an MRI study. These involve various dangers posed by the strong magnetic field that exists in the scanning room.

Before you begin scanning at the BIC, you are obliged to watch an MR safety video. The video is approximately 1.5 hours long. Please contact our MRI Technicians by emailing them at mrtechs.neuro@mcgill.ca or telephone at 514-398-6844 to arrange a time to view the video here at the BIC. It is also suggested that you please read the following three pdf documents regarding MRI safety:

• American College of Radiology White Paper on MR Safety
  
  
• MR Safety by Carolyn Roth, R.T.
  
  
• Safety Precautions in MR Environments by the Emergency Care Research Institute
  
  

Your Equipment

NO FERROMAGNETIC METAL OBJECTS IN THE MR SCANNER ROOM!

These are attracted to the magnet with great force, and can pose an extreme hazard. If you are in doubt about an object, ask the MR technicians or MRI Lab personnel before bringing it into the room. Examples of potentially dangerous objects include the following:

• scissors
  
• screwdrivers and wrenches
  
• coins
  
• pencils and pens with metal parts
  
• cellphones, pagers, or handheld computers
  
• wheelchairs, stretchers, canes
  
• IV poles, pumps
  

Your Subject

• metallic clips, screws or plates
  
• metallic implants
  
• metal filings, shrapnel, or bullets
  
• pacemaker
  
• artificial heart valves
  
• intrauterine devices
  
• tattoos, or permanent eyeliner
• makeup which may contain metallic iron oxide
  
• any other ferromagnetic metal objects
  
• eyeglass frames - metal frames must never be used by subjects inside the scanner
  (ask us about our special MR compatible eye glasses which your subject can use inside the scanner)

Most new surgical metal implants are made of high quality materials which are non-magnetic and safe for MRI use. Dental fillings and most bridgework is okay, but they may cause an artefact in the brain images.

NO POTENTIAL CURRENT LOOPS INSIDE MAGNET

The scanner will wipe out magnetic strip cards (credit cards, bank cards, etc.) and can damage watches. These items should be left in the console room.

Scanning Procedure

• The MR Research Committee has approved your study and protocol, and you have the printed MR Requisition form.
• On the day of your scan, you show up at the MRI Unit with your subject 15 minutes before your scheduled starting time. And your subject has signed your consent form.
• Individuals who will enter the room containing the MRI scanner remove all metal objects, magnetic cards, and watches.
• You go over the protocol with the techs and set up any stimulus, prompting, or feedback equipment and software you need.
• The subject is placed in the scanner by the techs and the immobilization system is adjusted.
• The projector is turned on and you ask your subject if they can see the screen properly.
• A series of anatomical scans is performed:
  
  • A 30 second localizer acquisition
    
  • A 10 to 15 minute T1-weighted 3D anatomical scan
    
• The functional scanning runs are usually performed after the anatomical scan. Each usually lasts about six minutes, but this depends on the number of frames you have and the repetition time between frames.
• You may speak to your subject via the scanner's intercom system in between the functional runs.
• At the end of the experiment, the subject is removed from scanner and the experimenter packs up their equipment and leaves the scanner area clean and ready for the next group.
• Don't forget to pick up your watches and wallets from the console room!
• Back at your lab, you should verify that all scans have been successfully transferred to the BIC server. Let the MR technicians know if there was a transfer problem for your images. Data on the scanner will be deleted after seven (7) days unless you notify the technicians of any problems (in person or at ext. 6844).