Brain Imaging Identifies Iron Deposits Linked to Cognitive Decline

February 20, 2020

New MRI technique reveals iron accumulations that could lead to Parkinson’s dementia prediction.

Predicting which patients with Parkinson’s disease will go on to develop dementia could be possible with a new MRI technique that detects iron deposits in the brain.

According to new research, published in the Journal of Neurology, Neurosurgery, and Psychiatry, tracking the collection and build-up of iron in the brain with a technique called quantitative susceptibility mapping could, potentially, help providers identify which patients will eventually develop dementia, possibly helping them devise more tailored treatment options.

The technique can be used to keep tabs on progressive declines in thinking, memory, and movement in patients with Parksinson’s, according to a University College of London team led by Rimona Weil, Ph.D. This finding represents a shift in how providers can approach monitoring and providing care for these patients.

“Iron in the brain is of growing interest to people researching neurodegenerative diseases, such as Parkinson’s and dementias. As you get older, iron accumulates in the brain, but it’s also linked to the build-up of harmful brain proteins,” Weil said in a statement. “So, we’re starting to find evidence that it could be useful in monitoring disease progression and, potentially, even in diagnostics.”

Iron accumulation in the brain is natural over time, but excess levels are toxic and can lead to permanent protein modification. Existing research has shown that alongside the build-up of amyloid and tau (proteins associated with both Alzheimer’s and Parkinson’s dementia), iron amasses in affected brain areas, as well.

Approximately 50 percent of patients with Parkinson’s go on to develop dementia, but it’s impossible to predict the timing or severity of each case. To date, no reliable measures exist to track the progression of the disease in the brain, leaving clinicians to rely on symptom monitoring to assess patients. Even conventional brain imaging can’t accurately assess what’s going on with the disease until it reaches later stages, and by then, the patient has already suffered significant loss in brain volume.

To determine the efficacy of quantitative susceptibility mapping, the team tested thinking, memory, and motor function in 97 people who were diagnosed with Parkinson’s within the last 10 years, as well as 37 healthy individuals. Using the technique with MRI scans, they identified iron accumulation in the hippocampus and thalamus and determined it was connected to poor memory and thinking scores. Additional iron build-up in the putamen brain region was linked to poor movement scores, pointing to more advanced disease.

These three areas are known to be associated with Parkinson’s symptoms, so finding iron deposition in them could play a vital role in evaluating treatment efficacy over time, the researchers said. It’s also possible that tracking iron deposits in the brain could allow for early diagnosis of Parkinson’s or other neurodegenerative diseases in the future, they added.

“We were surprised at how well the iron levels measured in different regions of the brain with MRI were correlated with cognitive and motor skills,” said study co-author Julio Acosta-Cabronero, Ph.D. “We hope that brain iron measurement could be useful for a wide range of conditions, such as to gauge dementia severity or to see which brain regions are affected by other movement, neuromuscular and neuroinflammatory disorders, stroke, traumatic brain injury, and drug abuse.”

The research team is continuing to follow the study participants, tracking their disease progression, as well as whether they develop dementia and how those measurements correlate to changes in iron levels in the brain.