Dec. 7 – The University of Illinois at Chicago (UIC) has completed safety trials of the 9.4 Tesla (T), which may soon offer physicians a real-time view of biological processes in the human brain. The study, supported by UIC and the State of Illinois Capital Fund, was published in the November issue of Journal of Magnetic Resonance Imaging, focused on MRI safety.
Researchers and physicians said they hope that the 9.4T will usher in a “new era of brain imaging in which they will be able to observe metabolic processes and customize healthcare.”
The 9.4T magnet has a field strength more than three times that of current clinical units. UIC's researchers said the 9.4T is the first such device large enough to scan the head and visualize the human brain. "Because the more powerful magnet allows us to visualize different types of molecules, we are seeing activity in the brain along a completely different dimension," said Keith Thulborn, MD, director of UIC's Center for Magnetic Resonance Research.
According to researchers, current MRI visualizes water molecules to track biochemical processes. By visualizing the sodium ions involved in those processes, the 9.4T permits researchers to directly follow important energy-consuming processes in the cellular machinery in the brain.
In the safety trial, 25 healthy volunteers (12 men and 13 women) were randomly exposed to the 9.4T scanner with a static magnetic field and sodium imaging. They were also exposed to a mock scanner with no magnetic field. An audio recording simulated the sound of a real scanner. Vital signs and cognitive ability were measured in all volunteers before and after the sodium imaging in the 9.4T and the mock scanning.
The results showed “no significant changes in heart rate, blood pressure, respiratory rate or other vital signs when volunteers were exposed to either the magnetic field or the imaging.” There were no significant differences in the cognitive testing of volunteers following mock versus real scanning and the most frequently reported discomfort was lightheadedness or vertigo when being moved into the magnetic field. A few subjects reported a metallic taste, nausea or a visual effect of seeing sparks but the sensations went away once they were stationary in the magnetic field, according to Thulborn and colleagues.
The researchers concluded that exposure to a 9.4T static magnetic field does not present a safety concern. With the FDA-required safety trials completed, UIC researchers will begin to put the 9.4T to use. "This initial evaluation of safety is only the first step towards realizing metabolic imaging of the human brain," Thulborn said. "We are now moving toward patient studies of sodium imaging and towards safety testing for oxygen and phosphorus imaging in humans. These early metabolic signatures of cellular health have great potential to advance detection and monitoring of diseases in the earliest stages, when treatment can produce the greatest benefit."