University Of Florida Opens Powerful New Window For Visual Studies Of Human/Animal Organs And Tissues

Weighing 24 tons and carrying a price tag of $2.4 million, the magnet was hoisted gingerly from a semi truck by a construction crane and lowered through the opened roof of a steel-encased building at the UF Brain Institute. An additional $700,000 to $800,000 worth of computers and ancillary parts will be installed over the next two months before the system becomes operational.

The new magnet has a unique combination of 11.7-tesla magnetic field strength --- 234,000 times stronger than the Earth's natural magnetic force --- and a 40-centimeter cylindrical chamber that will accommodate anesthetized animals up to the size of 15- to 18-pound primates. The next most powerful magnetic resonance imaging (MRI) system, located at the University of Minnesota, has a 9.4-tesla magnet with a 31-centimeter chamber.

"The level of magnetic force makes a big difference in imaging capability, and thus this technology will revolutionize research into all parts of the central nervous system," said Dr. William Luttge, executive director of the campuswide UF Brain Institute.

"This new magnitude of imaging capability will strengthen studies of brain and spinal cord injuries, stroke, epilepsy, tumors and various neurodegenerative diseases, including Alzheimer's and Parkinson's diseases," Luttge said. "With this technology, scientists also will be able to assess the safety and potential benefits of high-powered MRI scanning for clinical use in detecting disease and guiding surgery, as well as the delivery of therapeutic drugs or radiation."

Once the magnet is electrically charged and connected to computers that will direct its functions, it will generate three-dimensional pictures of tissues in animals and in human/animal tissue samples with much finer resolution than can be achieved with the conventional 1.5-tesla MRI scanners used in human medicine.

The U.S. departments of Defense and Veterans Affairs supported the UF Brain Institute's purchase of the magnet and its components through a 1996 cooperative award of $13.3 million. UF scientists hope to expand collaboration with both agencies in studies of brain and spine injuries and diseases that affect military veterans.

Dr. Kenneth Berns, UF's interim vice president for health affairs, said the 11.7-tesla magnet will strengthen the pioneering UF-VA studies under way to assess the safety and effectiveness of embryonic nerve tissue transplants in human patients with complicated wounds resulting from spinal cord injury. The new magnet will enable the researchers to assess, in animal models, what happens to nerve tissues that are implanted at or near the site of a spinal cord injury.

A large number of scientists associated with the Brain Institute, including faculty in the Center for Structural Biology directed by Thomas Mareci, look forward to using the new scanner to achieve greater clarity in medical imaging. The technology will enable them to:

* generate highly detailed images of structural, chemical and electrical processes taking place inside the brain and spinal cord region in living animals --- without having to sacrifice the animals in order to analyze their organs and tissues;

* see how brain tissue in anesthetized animals responds to various stimuli, including sounds, movement, touch, visual images and the delivery of drugs or other therapies;

* locate and plot the boundaries of tumors and other lesions so therapeutic radiation or surgery can be targeted directly to the site of the problem; and

* measure changes in physiological functions such as blood flow and cell water motion caused by injuries and stroke.

Steve Blackband, a physicist who directs the Brain Institute's Advanced Magnetic Resonance Imaging and Spectroscopy Facility, says the magnet will greatly aid his studies of stroke in animal models. He plans to use it in efforts to define the mechanism and scope of brain and nervous system damage caused by stroke --- information that cannot be obtained with standard clinical MRI scanners. Through functional imaging in living animals, he hopes to answer questions about how stroke damages brain tissues over time and what happens in the stroke-damaged region after drugs are given in an effort to stop the brain cell deterioration.

Ben Inglis, a UF neuroscientist, is excited by the ongoing opportunities to improve imaging technology to aid discoveries that can be applied to patient care. He is part of a team that has developed techniques for obtaining more information at the cellular level from the images generated through MRI.

The magnet becomes the fifth in an array of research-dedicated MRI systems at the Brain Institute offering various magnetic field strengths for use in different studies. An additional 3-tesla human MRI scanner at the Gainesville VA Medical Center is shared with UF.

UF's new imaging system also will be an added resource for the Tallahassee-based National High Magnetic Field Laboratory, of which the UF Brain Institute is the biological arm.

The world's most powerful imaging research tool made a long journey to UF --- from the manufacturing plant of Magnex Scientific near Oxford, England, to a port in Miami where it cleared customs inspection before being trucked to Gainesville.

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Sidebar

What is MRI?

For patients, magnetic resonance imaging, or MRI, is a painless procedure that involves being placed on a table that can be slid inside a chamber. A powerful magnetic field inside the chamber causes nuclei within cells throughout the body to line up like compass needles. A second, less powerful magnetic field then is introduced, causing the nuclei to spin like tops and thereby generate detectable signals. Computers capture the signals and translate them into an image. The more powerful the magnet, the greater the number of nuclei that respond, which in turn increases the strength of the signal and the clarity of the images.

Scientists are able to determine chemical makeup and structure of the person, animal or tissue samples undergoing MRI because the nuclei from different types of molecules oscillate at different, characteristic frequencies. Using mathematical techniques and aided by sophisticated computer hardware and software, scientists can determine the frequencies that comprise a given signal, figure out what type of molecules they represent and convert the information into an image.

Since the human body is made largely of water, most human MR images essentially show the distribution of water in tissue. While X-rays provide clear images of hard tissues, such as bones, MR-scans have enabled scientists and health-care professionals to see soft tissues with ever-improving clarity, greatly contributing to knowledge of living anatomy. Contemporary high-powered MRI scanners used in research can generate three-dimensional images, revealing not only anatomical structure but also chemical and electrical processes as they occur in living animals.