MRI Facilities:

The scanner, a 3.0 Tesla GE SIGNA MRI, installed in Oct. 2000, and recently upgraded to the EXCITE hardware platform in April 2005. The system has advanced imaging gradients with a maximum amplitude of 40 mT/m and a slew rate of 150 mT/m/msec and 8 fast (500 kHz) receiver channels (an upgrade to 16 channels has been scheduled for late 2005). The ability to develop custom pulse sequences for the scanner is provided by GE using a software development package - EPIC. Brain imaging studies (fMRI, structural and DTI) are done using either a quadrature birdcage coil or an 8-channel array head coil supplied by GE. Parallel imaging may be performed using the 8-channel array coil and GE's ASSET software option.

Visual stimulation can be delivered by using an advanced fiber optic goggle system (Avotec), the high resolution Visuastim XGA system (Resonance Technology), or using back-projection with an LCD projector and a screen at the end of the table. The Avotec fiber optic goggles are interfaced with SensoMotoric Instruments eye-tracking system (sampling rate of 50 HZ). This eye-tracking system yields four different analyses: percentage analysis, pictorial analysis, order of object vs. time, and pupil diameter vs. time.

Auditory stimulus is presented using a pneumatic headphone system (Avotec). All auditory stimuli are presented through a digital equalizer that is optimized for tone and clarity.

Stabilizing patients to minimize head movement is critical for MRI studies. The lab has three head stabilizing methods: bite bars, vacuum pillow, and foam inserts.

Collection of electrodermal activity during MRI scanning is achieved using a Coulbourn Instruments skin conductance coupler with 8 mm Ag-AgCl electrodes placed on the tips of the index and third finger. The electrodes are filled with a NaCl paste (49.295 grams of unibase and 50.705 grams of isot. NaCl 0.9%). The electrode leads are shielded and the signal low pass filtered to reduce RF interference from the scanner. The skin conductance signal is then digitized and sampled at 20 Hz using a National Instruments DAQPad 6020E. Digital event markers are simultaneously output from the stimulus presentation PC to the DAQPad, to enable precise time alignment of skin conductance responses with stimuli onsets/offsets.

To acclimate patients to the unique environment of the MRI scanner the lab houses a simulator room. This room has a mock MRI scanner, another Avotec fiber optic goggle system, and auditory system with two control computers. A motion detection system (based upon linear accelerometers) with video feedback is available for training subjects to not move in the scanner. This room is used to introduce subjects to the identical experimental procedures that they will experience in the actual scanner. This is done to ensure subject comfort and data quality.

The MRI facilities are supported by a full-time physicist, imaging technologists, and research staff.

 

Want to start your own MRI study?

Sample MRI Imaging Protocol & Parameters (excel format)

Sample MRI Images :

High Resolution Anatomical Images 

Functional MR Images

Diffusion Tensor Images