The short-bore GE Signa Excite MRI system is a 60-cm-bore, whole-body MRI system with a high-homogeneity, actively-shielded magnet with resistive, passive, and superconducting and high-order shims. The system computer-architecture is based on a Linux workstation with Intel Xeon dual processors with hyperthreading. The gradient system is a TwinSpeed dual gradient design. The radio frequency (rf) system provides a 35 kW rf amplifier, 16 quadrature expandable channels, and eight high-bandwidth receivers in addition to the quadrature transmit/receive body rf coil, the quadrature transmit/receive head rf coil, and the eight-channel array head rf receive coil. This system allows improved high-resolution, high-speed echo-planar imaging (EPI) through parallel imaging across body applications. It also allows imaging resolutions up to 256 x 256, oblique plane imaging, graphics prescription, and automated reconstruction with EPI sequences. These features make the system ideal for fMRI. This scanner is housed at the Keck Imaging Center.
The long-bore GE Signa Excite MRI system is a 55-cm-bore, whole-body MRI system with a high-homogeneity, actively-shielded magnet with resistive, passive, and superconducting shims. The gradient subsystem is a shielded gradient coil (CRM) capable of operating at slew rates up to 150 mT/m/sec and at peak gradient amplitudes up to 40 mT/m. This performance allows high-resolution echo-planar and diffusion-weighted imaging to be conducted anywhere in the body. The system computer-architecture is based on a Linux workstation operating as host with a dedicated signal acquisition subsystem, the transceiver processing system. The rf system contains a four-channel receiver module, low-noise digital rf subsystem and rf frequency synthesizer, quadrature transmit/receive body rf coils, quadrature transmit/receive head rf coils, and an eight-channel array head rf receive coil. This system allows improved high-resolution, high-speed EPI through parallel imaging. It also allows imaging resolutions up to 256 x 256, oblique plane imaging, graphics prescription, and automated reconstruction with EPI sequences. These features make the system ideal for fMRI. This scanner is housed in the Department of Biophysics.
This resource mimics the spatial and aural environment of a functioning scanner. It is used for subject training and psychophysical studies. It is operated by the Medical College of Wisconsin.
The Bruker BioSpec system has an actively-shielded 9.4 Tesla magnet with a 31-cm warm bore. This system has magnetic field uniformities of 0.1 ppm over a 70-mm DSV and 10 ppm over a 180-mm DSV. To keep such high levels of magnetic field uniformity, there are 12 user-adjustable shim coils. This infrastructure is in place to augment the vendor-supplied shims with six additional shims coils, which can be used to further enhance magnetic field uniformity for imaging and spectroscopic studies. Gradients up to 100 mT/m can be generated along all three axes. The radio frequency system has two transmission channels capable of experiments on 1H, 19F, 13C, 14N, and 31P nuclei, and two matching receiver channels capable of 16-bit resolution at a 2 MHz sampling rate. This hardware allows us to gather high-quality imaging and spectroscopic data since the shim system is able to generate extremely uniform fields and the gradients, in conjunction with the rf transmission and receiver subsystems, allow collection of data at extremely high rates, which is necessary for fMRI studies.
This instrument is a hybrid four-detector microSPECT with integrated X-ray CT module (FLEX Triumph [microSPECT/CT], Gamma Medica – Ideas).
The integrated cone-beam X-ray CT system is situated on same axis as the SPECT system, providing attenuation correction and co-registered X-ray CT and SPECT tomographic images. Technical features of the CT are as follows: The X-OT, CT sub-system, is equipped with an advanced CMOS digital X-ray detector technology and has the flexibility to perform a wide range of scanning. The X-OTM system allows researchers to image a large range of test subjects with its 9.3 cm diameter by 9.7 cm axial field of view, 118.4 mm x 112 mm X-ray CMOS detector with 368 x 2240 pixels and 50 μm pitch X-ray generator tunable from 50 to 80 kVp. Scout View for graphically assigning acquisition and reconstruction ROIs. Live Fluoro View for X-ray guided animal positioning. Delivered X-ray dose is < 2 cGy (continuous rotation mode). User selectable CT reconstruction options optimize soft tissue contrast or spatial resolution. User selectable X-ray detector binning from 1 x 1 to 4 x 4 optimize resolution and scanning speed. Acquisition graphical user interface displays projection data during a scan. User is able to select step or continuous rotation scan mode.
Features of the microSPECT scanner include broadband NaI(Tl) SPECT detectors with user interchangeable multipinhole aperture plates and parallel hole collimators, and volumetric reconstruction with various filtering/reconstruction algorithms. The multipinhole (5 pinholes per detector) SPECT imaging will enable a sensitivity level of greater than 1000 cps/MBq for dynamic studies of fast kinetic biological events. The multiplexed SPECT imaging with overlapping image projections on the detectors allows a maximized image magnification with sub-mm spatial resolution. The system has gated imaging and list-mode with dynamic imaging capabilities for quantitative SPECT imaging and dual- and multi-isotope studies.
Extensive electronic test equipment including:
- Agilent E5501B Phase Noise Measurement System
- HP3577A Network Analyzer (5 Hz–200 MHz)
- HP8510B Network Analyzer (10 MHz–20 GHz)
- HP8722D Network Analyzer (50 MHz–40 GHz)
- HP8566A Spectrum Analyzer (100 Hz–22 GHz)
- HP8596E Spectrum Analyzer (9 KHz–12.8 GHz)
- HP8564E Spectrum Analyzer (9KHz–40 GHz)
- HP54100A Digitizing Oscilloscope
- Frequency counters to 40 GHz
- Ansoft High Frequency Structure Simulator (HFSS)
- This state-of-the-art computer program running on an HP735 workstation is used for solution of Maxwell's equations. It permits objective (rather than intuitive) design of surface coils and may be useful for modeling rf field distributions in the brain during fMRI studies.