Three technological centerpieces of Oregon Health & Science University's new Advanced Imaging Research Center (AIRC) will be shipped, trucked, lifted and eased into place during the upcoming weeks. The center, which initially specializes in magnetic resonance imaging (MRI), will eventually 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 an adjunct professor of physiology and pharmacology in the OHSU School of Medicine. "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 to be installed is a 3 T magnet, which is scheduled to arrive at OHSU Jan. 3. The device, which weighs approximately 15 tons, will be lifted 30 feet by a crane and placed into the building via a wall opening left during construction. (Additional details will be released prior to this event for reporters wishing to cover the arrival.)
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 30 tons (approximately 60,000 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 are being made to ensure the safe transfer of the machine. (Though massive, this magnet also is extremely delicate.) The delivery is scheduled for a Saturday due to road closures and likely travel delays caused by the arrival. Furthermore, the viaduct roadway leading to the Biomedical Research Building loading dock is being reinforced to handle the load. Special, high-powered air cushion devices will be used to ease the magnet into place. It must be precisely positioned (millimeters) within a custom magnetically shielded enclosure, comprising 1 million pounds of steel, which OHSU has constructed especially for this purpose. After this, it will undergo an initial procedure to test for any damage incurred during shipment.
The 7 T MRI magnet is currently en route to the United States from the United Kingdom plant where it was constructed. Once the ship carrying it arrives in Long Beach, Calif., in early January, the magnet will be transported by truck to Portland with a scheduled OHSU delivery date of Jan. 21, 2006.
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 will have a 12 Tesla magnet. 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. OHSU's 12 Tesla magnet is expected to arrive in early spring.
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 integrity 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 impermeability in the normal brain, and it's 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.
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 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.
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. Fund-raising continues through June 30, 2006, with the Biomedical Research Building as a key capital priority.