MRI of the Future: New Test Predicts Dementia Risk Decades In Advance

Scientists have developed a new way to measure the rate of aging using brain imaging using magnetic resonance imaging. This technique, called DunedinPACNI, allows for more accurate predictions of who is at higher risk of developing diseases such as dementia, frailty, and even premature death. It helps understand how the brain reflects the body's aging and can be a useful tool for preventing health problems before they arise.

Aging is a natural process that affects us all. Over time, our bodies undergo gradual changes that affect various organs and systems, such as the heart, lungs, kidneys, and even the brain. However, not everyone ages in the same way or at the same rate.

Two people of the same age can have very different health conditions. This is why scientists are increasingly interested in measuring the rate of aging, that is, how quickly a person's body is deteriorating over the years.

With this information, it is possible to better understand disease risks and assess whether treatments or lifestyle changes can actually slow this process.

In recent years, researchers have begun using what they call "epigenetic clocks" to try to estimate a person's biological aging. These clocks are based on chemical changes in DNA called methylation, which occur naturally with age.

Early such clocks attempted to predict only a person's age, but this didn't reveal much about their actual health. Later, more advanced clocks emerged that used health data to estimate who might be at higher risk of death or disease. But these models still had a limitation: they used data from different people at single points in time, rather than tracking the same person's aging over time.

To address this problem, scientists followed a group of over a thousand people born between 1972 and 1973 in New Zealand, the so-called Dunedin Study. Over the course of 20 years, researchers collected health data from these participants at ages 26, 32, 38, and 45.

They measured 19 key indicators of physical health, such as blood pressure, cholesterol, lung function, oral health, and others. Using this information, they created a measure called the Pace of Aging, which shows how much a person's health is deteriorating over time.

More recently, scientists have developed a way to estimate this Pace of Aging by analyzing a single DNA sample. This version, called DunedinPACE, has proven useful in predicting disease and even early death.

However, not all studies have access to DNA data, especially in the field of brain health. Therefore, researchers decided to create a new version based on brain images obtained by magnetic resonance imaging (MRI), a safe and common technique for observing brain structures.

The new tool was named DunedinPACNI (PACNI stands for "Computed from NeuroImaging"). To develop it, scientists analyzed brain MRI scans taken at age 45 from participants in the Dunedin Study.

The idea was to use the images to train a computer model capable of "learning" which patterns in the brain are linked to faster or slower aging. This approach is innovative because, instead of trying to guess a person's age (as previous models did), it attempts to directly predict the rate of aging based on brain structure.

Imagine a tool to measure your aging rate while you're still reasonably healthy. Now, a single brain scan can reveal your aging rate and your risk of dementia and disability years from now, while you still have a chance to improve your health. Credit: Ethan Whitman

To test the effectiveness of DunedinPACNI, researchers used data from other large international studies, such as the UK Biobank (UK), the Alzheimer's Disease Neuroimaging Initiative (ADNI, USA), and BrainLat (Latin America).

Across all these groups, the new model was able to predict who would be at higher risk for cognitive problems (such as memory loss), brain atrophy (reduction in brain volume), dementia, and even early death. It also proved effective in predicting who would have poorer overall health in the future.

The figure shows how the volume of the hippocampus, a part of the brain important for memory, decreases with age, and how this reduction is related to the rate of aging measured by a new technique called DunedinPACNI. In part a, we see graphs with several colored lines representing different people from the ADNI (left) and UK Biobank (right) studies. Each line shows the change in hippocampal volume over time. The colors indicate the rate of this loss: red means faster loss (more accelerated brain aging) and blue means slower loss. In part b, we see two points with bars (called a forest plot) showing that people with higher DunedinPACNI scores, meaning those who are aging more rapidly according to this new marker, tend to lose hippocampal volume more rapidly as well. This suggests that the DunedinPACNI tool can indeed predict an early sign of brain aging. In short: the faster a person ages according to this new technique, the faster their hippocampus shrinks, a possible sign of risk for diseases like Alzheimer's.

DunedinPACNI represents a major breakthrough because it can transform standard MRI scans into powerful tools for reliably and accurately measuring aging.

It not only assesses the brain, but also acts as a general "thermometer" of the body's health. This can help doctors, scientists, and even healthcare systems identify who is aging faster and who could benefit from preventative treatments, even before symptoms appear.

READ MORE:

DunedinPACNI estimates the longitudinal Pace of Aging from a single brain image to track health and disease

Ethan T. Whitman, Maxwell L. Elliott, Annchen R. Knodt, Wickliffe C. Abraham, Tim J. Anderson, Nicholas J. Cutfield, Sean Hogan, David Ireland, Tracy R. Melzer, Sandhya Ramrakha, Karen Sugden, Reremoana Theodore, Benjamin S. Williams, Avshalom Caspi, Terrie E. Moffitt, and Ahmad R. Hariri 

Nature Aging. 1 July 2025

https://doi.org/10.1038/s43587-025-00897-z

Abstract: 

To understand how aging affects functional decline and increases disease risk, it is necessary to develop measures of how fast a person is aging. Using data from the Dunedin Study, we introduce an accurate and reliable measure for the rate of longitudinal aging derived from cross-sectional brain magnetic resonance imaging, that is, the Dunedin Pace of Aging Calculated from NeuroImaging (DunedinPACNI). Exporting this measure to the Alzheimer’s Disease Neuroimaging Initiative, UK Biobank and BrainLat datasets revealed that faster DunedinPACNI predicted cognitive impairment, accelerated brain atrophy and conversion to diagnosed dementia. Faster DunedinPACNI also predicted physical frailty, poor health, future chronic diseases and mortality in older adults. When compared to brain age gap, DunedinPACNI was similarly or more strongly related to clinical outcomes. DunedinPACNI is a next-generation brain magnetic resonance imaging biomarker that can help researchers explore aging effects on health outcomes and evaluate the effectiveness of antiaging strategies.