Tens of millions of people across the globe are estimated to have Alzheimer’s and the prevalence of the brain disorder is only accelerating with the aging of the global population. A protein called “tau,” which forms tangles in Alzheimer’s patients’ neurons, is the disease’s key marker.

The specialized MRI technique visualizes neuromelanin, a dark pigment related to the melanin that colors skin, in the control center of noradrenaline neurons. This is important because “there's evidence that the noradrenergic area of the brain is the part that actually starts accumulating tau first, years prior to the emergence of any symptoms” Dr. Cassidy says.


Alzheimer’s was examined in this study, but Dr. Cassidy is pioneering the use of this imaging method in different contexts, exploring how it might answer different questions for a wide range of psychiatric conditions. There’s a wealth of possibilities, Dr. Cassidy says.

The neuromelanin-sensitive MRI has been used to visualize degeneration of neurons in Parkinson’s disease and healthy aging. Schizophrenia and addiction have been examined. Cassidy and colleagues are next exploring its relevance for attention deficit hyperactivity disorder (ADHD).

“It really opens the door to examining these brain systems in humans, in vivo, in pretty much any disorder where it can be relevant. After all, if it is telling you something about the dopamine system or the noradrenaline system, those are two brain systems that are relevant for almost any condition in neurology or psychiatry,” he says.

Dr. Cassidy began collaborating with these McGill colleagues starting in 2018 and convinced them to add the neuroimaging technique to complement the many other measures available. This is the first publication from this collaboration, but their work is ongoing. Future papers will look at the data in different ways and better incorporate longitudinal datasets to observe changes over time.

Dr. Cassidy has developed a fully automated method of how to look at the “neuromelanin-sensitive MRI” images. Previously, this work required manual tracing, making it very labor intensive and subjective. Now, a computer system handles the raw images.

There are hopes for commercialization. Dr. Cassidy and colleagues have partnered with a biotech company and a software company to develop their tools into a software package. It is awaiting approval from the FDA.

“This will ensure our tool could have the potential for clinical use by being fully automated and reliably provide neuroimaging measures without any manual step required or expert intervention. This is an advantage over many tools used in neuroimaging research that require much time and effort by experts in order to yield useable metrics from the raw images collected off the scanner,” he says.

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