A new brain imaging technique has detected tiny pulsing blood vessels that could reveal early Alzheimer’s disease and track changes linked to ageing.
Alzheimer’s disease is the most common form of dementia. It is currently the seventh leading cause of death and one of the major causes of disability in older people worldwide.
The method uses ultra-high field MRIs to measure microvascular volumetric pulsatility – the contractions of tiny vessels that pulse with each heartbeat.
Researchers developed the technique by combining two MRI approaches: vascular space occupancy (VASO), which measures blood volume changes, and arterial spin labelling (ASL), which tracks blood flow in the brain.
This marks the first non-invasive method for measuring these microscopic vessel pulses in living patients.
Senior author Danny Wang from USC’s Keck School of Medicine said: “Arterial pulsation is like the brain’s natural pump, helping to move fluids and clear waste.
“Our new method allows us to see, for the first time in people, how the volumes of those tiny blood vessels change with ageing and vascular risk factors.
“This opens new avenues for studying brain health, dementia, and small vessel disease.”
Previous studies connecting pulsatility to dementia, small vessel disease and stroke relied on invasive procedures.
The team showed that brain vessels pulse more strongly with age, particularly in deep white matter regions that enable communication between brain networks.
Increased microvessel pulses may disrupt this communication and accelerate memory loss and Alzheimer’s disease.
Other studies suggest rapid brain pulses could also impair the glymphatic system – the brain’s cleaning mechanism that removes beta-amyloid proteins that cause Alzheimer’s.
Arthur Toga, director of USC’s Mark and Mary Stevens Neuroimaging and Informatics Institute, said: “Being able to measure these tiny vascular pulses in vivo is a critical step forward.
“This technology not only advances our understanding of brain ageing but also holds promise for early diagnosis and monitoring of neurodegenerative disorders.
“By combining the two MRI approaches, researchers were able to track small changes in microvessel volume that would otherwise be missed.”
The team intend to further develop the technique so it can be used more widely on standard MRI machines. They suggest microvascular volumetric pulsatility could potentially serve as a non-invasive biomarker for early detection and intervention in Alzheimer’s disease.
