Introduction


The Mount Sinai Medical Center Cardiovascular MR Center (CVMRC) is a joint effort of the Cardiovascular Institute and Department of Radiology. The CVMRC is dedicated to the technical development, basic and clinical applications of MR imaging to the Cardiovascular system. The center is also committed to the education and training of interested researchers and clinicians in Cardiovascular Magnetic Resonance.

The CVMRC is located in the department of Radiology (20,000 square foot imaging facility in the Mount Sinai Medical Center) within the Imaging Science Laboratories (ISL) and the MR Imaging suite. The CVMRC occupies around 3,000 square foot and includes several MR imaging systems, the Image Processing Laboratory, the Advanced Electronics Laboratory, and the Small Animal Laboratory. In addition the CVMRC houses the MR Microscopy Laboratory and offices for the ISL faculty (4) and staff (4).
Magnetic Resonance Imaging: Whole Body Scanners

The MR Imaging suite has four state-of-the-art General Electric Signa 1.5 T MRI systems, 2 clinical, 1 clinical research, and 1 research (see below), which together perform over 15,000 patients per year. Three of these systems are equipped with the horizon ECHOSPEED option. All the systems are equipped with phased array coils capabilities, and are connected to the CVMRC via Ethernet. Each system has access to patient support resources, including Code Call.

The MR imaging research system for human and large animal studies is a 1.5 T whole body enhanced Cardiovascular /Neurovascular Interactive MR system (Signa, General Electric). Some of the features of this system are:
• Compact 1.5 T actively shielded magnet
• New generation of SGI based computer and workstation user interface
• Cardiac Resonance Module and gradient configuration (44mT/m maximum gradient strength and 150 mT/m/ms slew rate on all three axes
• High duty cycle gradient drivers
• 6 array processors for image reconstruction
• ± 125 kHz receiver bandwidth for a 4-channel phased-array coil; and ± 500 kHz receiver bandwidth for a single-channel receiver coil.
• Advanced gating algorithm with ECG leads with reduced gradient noise
• Interactive Cardiac Imaging Workstation
• Cardiac Phased Array Coils
The research MRI system is also equipped with a physiological monitoring system (Magnetic Resonance Equipments Inc.) including ECG, oxygen levels, and end tidal CO2 and blood pressure. A full resuscitation cart is available next to the system.


Magnetic Resonance Imaging: Future Research Scanners

Two dedicated research scanners will be installed in the newly constructed MR Research Suite (~2800 ft˛). The MR Research Suite of about 2800 ft˛ will house a 1.5 Tesla whole body Siemens Scanner (Sonata) and a 3 Tesla Siemens head dedicated scanner. In addition to the scanners it will also have patient waiting area, nurses station, toilet & lockers and computer/viewing/processing area.

The Sonata:
·Whole body scanner with 60cm bore size
·Actively Shielded magnet with patented external interference shielding
·1.60 m ultra-short design with full 40cm FoV
·Actively shielded 3-axis gradient system.
·Gradient system: cascade amplitfier producing 2000 V and 500 A, the most powerful in the industry. Producing a gradient strength of 40mT/m, rise time=200µs and a slewrate of 200T/m/s
·15 kW RF amplifiers
·Up to 8 RF preamp channels
·ąH spectroscopy
·Syngo software on an NT platform

The Allegra:
·Head dedicated scanner with 60cm bore size
·Actively Shielded magnet with patented external interference shielding
·55 cm bore diameter with 220mm FoV
·Actively shielded 3-axis gradient system.
·Gradient system: cascade amplifier producing 2000 V and 500 A, the most powerful in the industry. Producing a gradient strength of 40mT/m, rise time=100µs and a slewrate of 400T/m/s (For diffusion tensor imaging this will be able to produce b-values of over 10,000 s/mm˛)
·123.2 MHz ,15 kW RF amplifiers
·Up to 8 RF preamp channels
·Syngo software on an NT platform
·ąH spectroscopy
·Multinuclear spectroscopy will be available in 2002

Both systems will be equipped with the same software so that brain functional imaging and diffusion tensor software can be performed on both machines. Special cardiac sequences can also be run on the Allegra for in vivo animal studies.

The Allegra suite will be fully equipped to perform a variety of functional activation studies:
-Visual stimuli using a rear projection screen and LCD projector mounted in the scanner room.
-Auditory presentation using a calibrated audio system.
-A multi channel subject’s response recording using a fiber optic cable system.
-An 8 channel computer controlled olfactometer.
Magnetic Resonance Microscopy

A new high field MR microscopy system (Bruker Instruments, Inc.) for small animal and specimen work is available. The MR Microscopy Laboratory is located in the ISL adjacent to the MR Imaging suite. Some of the features of this system are:

HARDWARE:
• superconducting actively shielded magnet with 89 mm bore diameter, operating at 9.4T (Bruker Intruments, Inc.)
• actively shielded gradient coils, maximum gradient strength 20 G/cm or 100 G/cm
• exchangeable RF birdcage resonator with: 38 mm, 25 mm, 12 mm inner diameter probes
• probe supports user supplied air to maintain animal at physiological temperatures

SOFTWARE:
• the new system will support many types of MR pulse sequences. Relevant to our experiments are:
1) flow compensated gradient-echo 2D and 3D inflow angiography sequences.
2) improved multi-slice/multi-echo spin-echo imaging. Echoes may be added during signal acquisition to acquired images processing high signal-to-noise and variable T2-contrast.
3) fast-spin echo imaging (RARE) that should not only improve imaging speed but also signal-to-noise ratio. Several options are available of interest are: dual-echo RARE (e.g., or the simultaneous acquisition of both proton-density and T2-weighted images), and 3D RARE (e.g., for better spatial resolution and isotropic voxel acquisitions).
4) spin-echo diffusion imaging for plaque characterization.
• 3D MR data display and quantitative analysis that can be modified to tailor our experiments.

IMAGE PROCESSING:
Several computer workstations are available in the MISL: Seven Sun Sparc-20 and two SGI O2 workstations are available for programming, data and image transfer and processing, and image review. Several PCs, a flat bed scanner, and a color dye sublimation printer are also available for word processing, data analysis, slide and video preparation and image processing. Computer archival in form of DAT-tapes drives, ZIP-disks drives, and CD-RW are available. A variety of commercial, public domain, and in-house developed software packages are available for image transfer, processing, and display.