University of Wisconsin–Madison

About the MRI Scanner

MRI Scanner

The scanner, a 3.0 Tesla X750 GE Discovery, was installed in April 2009. Equipped with the most powerful gradients found in the industry, new water-cooled gradient amplifier and 64-bit data pipeline with dual blade processing. Custom pulse sequences are developed using GE’s EPIC software development package. Brain imaging studies are done using either a quadrature birdcage coil, 8-channel array head coil, 16-channel array head coil, 32-channel array head coil, 8-channel speech coil, or 8-channel array head coil for nonhuman primate imaging.

Visual stimulation can be delivered by using an advanced fiber optic goggle system or a high resolution back-projection system. Both goggles and back-projection systems 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.

MRI auditory stimuli are presented using either a pneumatic headphone system, a set of electro-dynamic headphones, or an active noise-canceling system.  Two of these systems are low profile and can be used with the 32 channel coil.   MRI sound levels are reduced in studies of sleeping young children using an acoustic foam insert.

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

Collection of peripheral physiological measures in the MRI are done using the Biopac MP150 system. The MP150 system provides high resolution (16 bit), variable sample rates for analog and calculation channels, 16 analog inputs and two analog outputs, digital I/O lines (automatically control other TTL level equipment), and 16 online calculation channels. The MP150 System provides high-speed acquisition (400 kHz aggregate), and Ethernet connectivity. Controlling the Biopac is the software, AcqKnowledge. This software is an interactive program that lets lab members instantly view, measure, analyze, and transform the incoming data.

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

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