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OHSU Joins the NIH in Obtaining a “Two-Of-A-Kind”  MRI Magnet

OHSU’s new Advanced Imaging Research Center has received its most most unique instrument. On Saturday, April 22, the AIRC took delivery of a 12Tesla (T) magnet, the centerpiece of a rare and cutting-edge MRI system. The 12T instrument with a magnetic field 120,000 times stronger than that of the Earth was purchased with assistance from a $1.75 million grant provided by the W. M. Keck Foundation. This is the third MRI magnet delivery for OHSU this year. In early January, a 3T magnet was lifted by crane into OHSU’s new Biomedical Research Building, the primary home of the AIRC. In late January, OHSU received delivery of a 60 ton, 7T magnet. Read the full news release. 

Streaming video

		Streaming video of 3 Tesla magnet arrival on Jan. 3, 2006 (8 mb)			Streaming video of 7 Tesla magnet arrival on Jan. 21, 2006 (20 mb)

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PORTLAND, Ore. - Three technological centerpieces of Oregon Health & Science University's new Advanced Imaging Research Center (AIRC) have been shipped, trucked, lifted and eased into place. The center, which initially specializes in magnetic resonance imaging (MRI), will house four,high-performance MRI instruments: two 3 Tesla (T) scanners, as well as 7 T and 12 T systems. Three of the MRI units, along with the AIRC offices and core staff, will be housed in OHSU's new Biomedical Research Building (BRB), which is nearing completion on OHSU's Marquam Hill Campus. Another 3 T system will be housed in an AIRC satellite facility at the Oregon National Primate Research Center on OHSU's West Campus.

"The arrival of these three high-field magnets is a momentous occasion for OHSU research," explained Charles S. Springer, Ph.D., AIRC director and a professor in the OHSU physiology and pharmacology department and the biomedical engineering department, as well as a member of the OHSU Cancer Institute. "While it will be many months before all three Marquam Hill instruments are operational, we are on the verge of becoming one of the top imaging research centers in the nation, both technologically speaking and personnel-wise." The AIRC, along with the arrival of Springer, took place through the Oregon Opportunity public/private partnership. The Oregon Opportunity was created to increase the health and economic benefits of OHSU research to all Oregonians.

The first new component is a 3 T magnet, which arrived at OHSU Jan. 3. The device, which weighs approximately 15 tons, was lifted 30 feet by a crane and placed into the building via a wall opening left during construction.

The second major MRI component to arrive is the largest in size and weight. The 7 Tesla MRI magnet, large enough for human subjects, weighs 35 tons (approximately 70,000 pounds). Due to the extreme mass of this cutting-edge piece of equipment, the foundation for this machine was poured in the BRB basement directly on the Marquam Hill bedrock underlying the building. With regard to installation, a series of careful preparations had to be made to ensure the safe transfer of the machine. (Though massive, this magnet also is extremely delicate.) The delivery took place on a Saturday due to road closures and slight travel delays caused by the arrival. During installation the magnet needed to be precisely positioned (millimeters) within a custom magnetically shielded enclosure, comprising one million pounds of steel, which OHSU has constructed especially for this purpose.

The 7 T MRI magnet came to the United States from the United Kingdom plant where it was constructed. After the ship carrying it arrived in Long Beach, Calif., in early January, the magnet was transported by truck to Portland.

There are only a handful of 7 T MRI systems for human subjects in the world at this time, with six currently operating in the United States. Only three other U.S. institutions house human-capable MRI instruments featuring magnets with fields greater than 7 Tesla.

The final MRI instrument to be installed in the Advanced Imaging Research Center BRB facility was a 12 Tesla magnet. The magnet arrived at OHSU on April 22. While of greater field strength than that of the 7 T magnet, this magnet weighs less (only 12 tons, 24,000 pounds)and is smaller. It is designed for human health studies in animals. Only one other 12 T magnet this large exists in the world. It is housed at the National Institutes of Health in Bethesda, Md.

AIRC Research

Since its 2003 opening in a temporary building on the OHSU Marquam Hill Campus, Advanced Imaging Research Center investigators have studied a variety of disease conditions that can be better understood or detected through MRI science. One example of this kind of research is being conducted by Springer; Xin Li, Ph.D., AIRC manager; and William D. Rooney, Ph.D., AIRC senior scientist. Together the three are developing new methods for interpreting MRI data. The scientists expect their work will provide clearer diagnoses of many cancers, including those of the breast and prostate. Their analysis, called the shutter speed model, allows researchers to account for the effects of the movement of water molecules in and out of cellular compartments in diseased and healthy tissue. In the case of tumors, using shutter speed analysis not only more clearly indicates the locations of tumors, it also allows researchers to distinguish between malignant and benign tumors at an early stage, and to monitor the response of the former to therapy.

Other examples of studies taking place in the AIRC include:

• Analysis of brain changes caused by drug use. It is hoped that these data will lead to new treatments and drug abuse prevention methods.
• Studies on the effects of blood hormone levels on memory.
• Research to understand how the brain is wired in the absence of vision, or rewires itself following vision loss.

Planned future studies using the new, higher-field AIRC magnets will allow scientists to map sections of the brain with increased resolution. Other research projects are geared toward improving quantitative measurements of the permeability of the blood-brain-barrier (BBB), a natural protective feature that prevents blood toxins from entering the brain. OHSU is the home of the Blood-Brain-Barrier Program, founded by Edward A. Neuwelt, M.D., professor of neurology and neurological surgery in the OHSU School of Medicine. The shutter speed model will allow the first accurate measurements and mapping of the BBB integrity in the normal brain, and its very slight compromise in the early stages of many pathologies. The investigators expect to map such subtle BBB vascular deficiencies early in multiple sclerosis, stroke, Alzheimer's disease, and more. Conversely, the blood-brain-barrier poses problems in trying to target brain tumors with chemotherapy: the therapeutic drugs are blocked as if they were natural toxins. So, quantitative measurements of the extent and duration of controlled BBB opening will be very important. Scientists at OHSU have already made several advancements in this area and hope to continue this important research.

Michael Jerosch-Herold, Ph.D., a cardiological MR scientist and associate professor of diagnostic radiology and cardiology in the OHSU School of Medicine, measures blood flow in myocardial tissue at rest and under stress. Collaborative work with Li and Springer shows that the shutter speed model also allows simultaneous measurement of myocardial blood volume under these conditions.

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MRI Technology Summarized

Magnetic resonance imaging is a technique developed to create high-resolution 3-D pictures of any location in the body. MRI uses computer-controlled radio frequency (RF) waves and magnetic field gradients inside large magnets strong enough to generate fields tens of thousands times stronger than the earth's magnetic field at its surface. The combination of the RF waves and this magnetic field causes the hydrogen nuclei of water and other molecules in the body to respond. RF signals from these responses can then be detected and used to create 3-D images. Unlike X-ray imaging or CAT (computed axial tomorography) scanning, MRI does not employ ionizing radiation and poses no inherent health risks to subjects.

Magnetic field strengths are measured in Teslas. (One Tesla represents a strength approximately 10,000 times that of the earth's magnetic field.) For instance, an MRI instrument with a 1.5 T magnet can potentially provide a superior image of the body region under study than one with a 1 T magnet. The main reason for this is that the strengths of the tissue water-hydrogen RF signals increase with increasing magnetic field strength. Prior to the arrivals of the AIRC high-field magnets, OHSU had two 1.5 T and two 3 T MRI units for use in clinical diagnosis.

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Funding

Springer was recruited to OHSU to establish the Advanced Imaging Research Center through the Oregon Opportunity, a $500 million public/private effort to make Oregon more competitive nationally in biomedical research that leads to new treatments and cures for disease.

In 2002 the state of Oregon and Oregon voters approved a $200 million public bond initiative to support the Oregon Opportunity. These public funds have been matched with more than $335 million in private donations from more than 71,000 individuals to support and expand OHSU's multiple missions and to build research infrastructure. For example, the W. M. Keck Foundation has just awarded OHSU a $1.75 million grant to help support the work of the AIRC and the cost of the 12 T MR instrument. Fund-raising continues through June 30, 2006, with the Biomedical Research Building as a key capital priority.

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Photos (click to enlarge, mouse-over for caption)

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*A.C. Silva, J.H. Lee, I. Aoki, and A.P. Koretsky, “Manganese-Enhanced Magnetic Resonance Imaging (MEMRI): Methodological and Practical Considerations,” NMR Biomed. 17:532-543 (2004).