Some aging-related changes can be hidden.
Danny Wang, professor of neurology, radiology, and biomedical engineering and Director of Imaging Technology Innovation at the Stevens Neuroimaging and Informatics Institute at the University of Southern California, examines these.
Dr. Danny JJ Wang is a Professor of Neurology, Radiology and Biomedical Engineering, and Director of Imaging Technology Innovation at the Stevens Neuroimaging and Informatics Institute, University of Southern California, as well as head of the Laboratory of Functional MRI technology (LOFT). Over the past 25+ years, his research has focused on the technical development and clinical translation of novel medical imaging technologies, with clinical applications related to cerebrovascular disorders, dementia, and neurodevelopment, as well as development at ultrahigh field strengths. He is a Fellow of ISMRM and AIMBE. He initiated the 7T Translational Alliance of North America (7TANA.org) to facilitate the clinical translation of ultrahigh field MRI. He recently authored a book, “Imaging Blood-Brain Barrier Dysfunction in Brain Disorders.”
New Brain Imaging Method Reveals Hidden Vascular Changes with Aging
With every heartbeat, our brain’s arteries expand and contract, sending a pulse through the vascular tree in the brain. These rhythmic changes help circulate the blood and cerebrospinal fluid. However, in a healthy brain, these pulses should be dampened when they reach the smallest blood vessels deep inside the brain, as a mechanism to protect the capillaries. When this process falters, it may contribute to conditions such as stroke, small vessel disease, or even Alzheimer’s.
Until now, scientists could only measure these pulsations in the brain’s larger arteries, missing what happens in the microvasculature—the arterioles and capillaries that directly nourish brain tissue. To fill this gap, my colleagues and I developed a new, non-invasive imaging approach using ultrahigh-field 7-Tesla MRI. This technology allows us to measure, in living people, how much the brain’s smallest vessels expand and contract with each heartbeat—a metric we call the microvascular volumetric pulsatility index.
We tested this method in young and older adults. Pulsations were strongest near the brain’s surface, fading in deeper tissue. In older adults, deep white matter had significantly stronger pulsations, especially in those with high blood pressure. White matter areas with increased pulsatility overlap with regions prone to ischemic lesions called white matter hyperintensity. These findings suggest aging and vascular risk may transmit pulses deeper into the brain, straining fragile vessels and causing health issues.
By capturing these subtle vascular dynamics in vivo, our technique opens new possibilities for detecting early signs of vascular and neurodegenerative disease. It may one day help us identify people at higher risk and monitor whether treatments are restoring healthy brain circulation.
Read More:
[Elsevier] – Imaging Blood-Brain Barrier Dysfunction in Brain Disorders
