At the University of Southern California (USC) and Siemens Healthcare US, a group of researchers have presented a new magnetic resonance imaging (MRI) model that closely observes cerebral blood vessels. Danny Wang and Fanhua Gua, the two lead researchers, have used VASO and ASL techniques to study the arteries and capillaries of the brain. Thanks to this breakthrough, it will now be possible to study the cerebrovascular system more closely and how it changes with aging and hypertension, which are directly linked to Alzheimer’s and dementia. Read on to learn more.
The brand new map of our brain
The subtle pulses of tiny blood vessels in the brain can at this moment be mapped in greater detail than ever before using a new imaging way. It’s the first noninvasive tool to quantify the expansion and contraction of microscopic arteries and capillaries in the living human brain.
“Arterial pulsation is like the brain’s natural pump, helping to move fluids and clear waste,” explains neurologist and senior author Danny Wang from University of Southern California (USC).
“Our new method allows us to see, for the first time in people, how the volumes of those tiny blood vessels change with aging and vascular risk factors. This opens new avenues for studying brain health, dementia, and small vessel disease.”
The perfect combination by the medical collaborators
The method was carried out at the University of Southern California in collaboration with the medical technology company Siemens Healthcare US. It combines two MRI techniques – vascular space occupancy (VASO) and arterial spin labeling (ASL) – to quantify subtle modifications in the volume of the brain’s vasculature.
The grown pulsation of arteries in the brain is closely connected to cognitive impairment, and some scientists have in mind that it might contribute to several forms of dementia, such as Alzheimer’s disease. However, some studies so far have been limited in what they can glean from living human brains, implying that much research is based on animals.
Wang, lead author and neuroscientist Fanhua Guo, and their team at USC hope their recent technique will aid fill that gap. They studied microvascular pulses in the brains of 11 young participants, in their 20s and early 30s, and 12 older participants in their mid-50s and early 60s.
Lately , investigators found pulses of blood in deep white matter sped up with age, and those older individuals with hypertension proved more modifications than most.
What the achievements aling
The achievements align with new animal studies, which proposes that the vasculature of white matter in the brain (composed of nerve fibers) pulses more with age or disease.
“Our method shows strong potential for both research and clinical use, enabling accurate imaging of the cerebral microvascular system and capturing volumetric pulsatility in gray matter and white matter,” the authors conclude.
Investigators are not yet sure the reason of why this is happening, but they have some hypotheses. The density of the brain’s microvascular system is thought to naturally decrease with age, and this reduction in volume and branching may mean that the arteries are not able to dissipate the pressures of every single pulse as well as they used to.
If that’s true, then to release the residual pressure, outer arteries in the brain’s white matter may increase the volume of their pulsations. That in turn could slow the flow of cerebrospinal fluid, which bathes the brain, and which is closely linked to aging and disease.
“These findings provide a missing link between what we see in large vessel imaging and the microvascular damage we observe in aging and Alzheimer’s disease,” says Guo, who is a postdoctoral researcher in Wang’s lab.
