New, extremely accurate magnetic resonance imaging, scanners may be able to identify people with Parkinson's disease and similar conditions most likely to benefit from new treatments, researchers said Monday.
The scanners, called 7T MRI, are able to detect damage to a small region of the brain called the locus coeruleus, or blue spot, which produces the chemical noradrenaline, they said in an article published Monday by the journal Movement Disorders.
Noradrenaline is involved in several brain functions, including thinking, attention, and motivation, according to the researchers.
"All of our brain's supply comes from a tiny region at the back of the brain," James Rowe, co-author of the paper, said in a press release.
"It's a bit like two short sticks of spaghetti half an inch long. it's thin, it's small and it's tucked away at the very base of the brain in the brain stem," said Rowe, a professor of clinical neurosciences at the University of Cambridge in England.
7T refers to the strength of the magnetic field used in an MRI scanner, with most of the more than 14,000 MRI scanners in the United States using weaker 3T or lower technology, according to the Organization of Economic Cooperation and Development.
Stronger MRIs have been shown to assist in the diagnosis of other movement disorders, including multiple sclerosis, in previous studies.
By spotting damage to the locus coeruleus, 7T could help those with Parkinson's and a related disorder, progressive supranuclear palsy, who do not suffer from motor symptoms and may not respond to dopamine-based drugs commonly used in both diseases, Rowe said.
L-DOPA is one of these dopamine drugs, which are designed to compensate for the loss of dopamine seen in patients with the two diseases, he and his colleagues said.
However, dopamine treatment does little for many of the non-motor symptoms of these diseases, they said.
Parkinson's and progressive supranuclear palsy are progressive brain diseases that not only affect movement, but also damage brain function, according to the Parkinson's Foundation.
Brain symptoms of these diseases can have profound effects on a patient's prognosis, affecting their survival and general well-being, as well as adding to stress and costs for their families, Rowe and his colleagues said.
Several drugs that boost noradrenaline have already been through clinical trials for other conditions, and have been shown to be safe and well tolerated, the Parkinson's Foundation says.
Damage to the locus coeruleus may be caused by a build-up of the protein tau in the brain and, when production of noradrenaline drops, it may lead to changes in the tau protein that result in its accumulation, the researchers said.
Some people with progressive supranuclear palsy lose as much as 90% of the noradrenaline-producing locus coeruleus, according to an earlier study by the same team.
While most scanners can show structures at the level of detail of a grain of rice, 7T scanners can provide resolution at the size of a grain of sand, allowing researchers to examine the locus coeruleus of study participants and confirm damage to the region, they said.
"The locus coeruleus is a devil to see on a normal scanner," Rowe said.
"We've wanted MRI scanners to be good enough to do this for some time," he said.