GE MR 750 3.0 Tesla Suites
The Brain Imaging and Analysis Center (BIAC) at Duke University houses two research-dedicated whole-body 3T human scanners (both operating on the newest GE MR750 platforms). The two 3T GE MR750 scanners use actively shielded magnets designed to restrict fringe magnetic fields. The scanners are equipped with high-duty-cycle 50 mT/m gradients at 200 T/m/s slew rate. The RF systems include volume birdcage head coils, eight-channel head coils, 32-channel head coils, and receiver amplifier arrays of 128 channels. The eight- and thirty-two- channel head coils are used for parallel imaging at high bandwidth up to 1MHz. To ensure high homogeneity critical for fMRI experiments at high field, the 3.0 T scanners are equipped with high order room-temperature resistive shimming coils in addition to the super-conducting shimming coils. In addition, both scanners use broadband transmission to enable multiple frequency excitation schemes important for multi-nuclei imaging and spectroscopy experiments. The scanners are controlled by Linux workstations, which are connected via a high-speed network interface.
An MRI-compatible physiological monitoring system provides continuous measurement of ECG, end-tidal CO2, respiration, and non-invasive blood pressure. Visual stimuli are displayed via computer projector on a screen within the scanner bore. Audio stimuli are presented using MR-compatible headphones. Somatosensory stimuli are delivered using a constant-current stimulator. Subject responses are obtained from a fiber optic response box and/or joystick. Custom software is used for physiological and artifact monitoring and for real-time data analysis.
Bruker 7.0 Tesla Small-Bore MRI Suite
BIAC's 7.0 Tesla scanner is a Bruker BioSpec system with a 31 cm bore size and active shield to restrict fringe magnetic fields. This scanner is equipped with two separate gradient systems, one at 20 cm diameter with 200 mT/m strength, the other at 12 cm diameter and 400 mT/m strength for high resolution microscopic MR imaging. It comes with broadband and dual-channel transmission, four-channel parallel receivers, as well as assorted RF coils for different nuclei, including 1H, 13C, 19F, 31P, to allow versatile imaging and spectroscopy experiments to be carried out. To facilitate animal handling, specialized animal cradles are in place to rats and mice, with mounting points for surface coils, fixation points for the animal, water bed for temperature conditioning, provision for inhalation anesthesia, and physiological monitoring equipment. The scanner is controlled by a Linux workstation, installed with PARAVISION software to coordinate synchronized communication among various hardware components.
MRI Simulation Facilities
To acclimate patients to the MRI scanner experience, the BIAC has constructed an MRI simulator system using a decommissioned GE scanner. The system includes a mock MRI scanner, a goggle-based auditory and visual stimulus presentation and data recording system, a head-movement monitoring system, and two control computers. The MRI simulator looks, sounds, and feels just like a real MRI scanner. This system is used to introduce participants to the identical experimental procedures that they will experience in the actual scanner, and to train children to participate in functional neuroimaging studies. This is done to ensure participant comfort and data quality.
BIAC faculty have also installed a WhisperRoom™ sound-attenuating chamber within the MRI simulator suite. This chamber is used for testing experimental paradigms and for behavioral studies, and it contains an eye-tracking system (Applied Science Laboratories).
GE NVi 4.0 Tesla (Retired)
After ten years of uninterrupted service at BIAC, our beloved 4T scanner now resides at the GE Magnet Factory in Florence, SC, this summer to serve educational purposes for the next generation of engineers and scientists.