A study of one of the newest magnetic resonance imaging (MRI) machines is being conducted at The University of Minnesota, Twin Cities with multiple sclerosis patients and controls. Housed at the Center for Magnetic Resonance Research is the machine with a 7 Tesla magnet. Tesla is the unit for measuring magnetic induction named for Nikola Tesla. This is one of the the highest power so far to be cleared for use on humans though there is a 9.4 Tesla for humans at the University of Chicago. The idea is that the more powerful the magnet, the more detail the scan will show and the more pointed the test will be for diagnosing and planning treatment of diseases like cancer and multiple sclerosis. The study at the University of Minnesota seeks to reveal the differences between information gleaned from three different levels of Tesla in both healthy individuals and people with multiple sclerosis. So what was participating in this study like?
Magnetic resonance imaging is scan technology that utilizes a powerful magnet to “see” similar to an X-ray but with few know health risks. Before the study, subjects signed informed consent agreements about the study and answered screening questions including queries about metal in the body and tattoos. Certain tattoos have a metallic compound to the ink, so queries about tattoos, when and where they were received, and the location of the tattoo on the subject’s body were relevant. An MRI scanner boasts a powerful magnet and when in use, the magnet can cause metal to heat up and tug. Precautions are taken to protect the subject from injury by making sure no metal is present.
The first part of the study was an office visit to test disability level. The battery of tests included balance, vision, and dexterity tests; cognition evaluation with a Paced Auditory Serial Addition Test (PASAT), and memory challenges. Next, the subject went to the Center for Magnetic Resonance Research for the scan. Our subject participated in just the scan of the machine with the 7 T magnet, though other participants underwent scans with different machines. Upon arrival, subjects were given scrubs to don and women were admonished to remove bras, since there can be a metal underwire. The research doctors explained that this 7 T magnet could cause dizziness, so once the subject was on the MRI platform; it would be moved in steps, not all at once. To experience what the subjects would feel, all of the study doctors had undergone the imagining, and all admitted they had experienced the vertigo.
Now it was time to go into the machine. Our subject was prone on the MRI platform, with a cage over the head, earplugs and a mirror to look at that showed a far wall instead of the blank inside of the machine. Headphones with music had been offered, but headphones in MRIs can be too loud or of poor sound quality, so our subject opted for earplugs only. When the platform motored slowly into the hole, it stopped for a minute, as promised, then continued. Our subject noticed a little of the vertigo, but nothing too severe.
Then the scan with loud mechanical clicks, low tones and screeches commenced, and inexplicably, our subject fell fast asleep. The scan lasted almost an hour. Once it was finished, exiting the machine produced some vertigo and there was noticeable grogginess – the effects of the magnet scan and slumber combined. Mild nausea persisted throughout that day as well as a metallic taste.
Results from this study appear promising as magnetic imaging advances. There are no lasting health risks from magnetic imaging, yet the information produced is vast and promises to advance research of different conditions and disease.
“We think that these new types of MRI measures may do a better job of showing the underlying damage to the brain in MS, compared with traditional MRI measures…. Comparing the traditional MRI measures to the new MRI measures should help us determine whether or not the new scans tell us more about brain injury in MS than the traditional MRI alone….”
--Study authors of Probing Multiple Sclerosis by Magnetization Transfer and Rotating frame T1ρ MRI led by Adam Carpenter, M.D.