October 17, 2025 - By Kathryn Sill

A team of Stanford researchers developed a non-invasive and contrast-free MRI method that successfully measures blood flow in children with moyamoya disease or with high risk of stroke.

Moyamoya disease is a rare condition that affects the blood vessels in the brain. In this disorder, fragile blood vessels grow around a blocked artery in an effort to bypass the obstruction. These vessels appear as a "puff of smoke" on imaging tests, which is how the disease got its name from Japanese researchers. It can affect both children and adults, typically causing symptoms such as mini-strokes, strokes, headaches, and seizures. There is currently no effective medication for moyamoya disease, and treatments like angioplasty or stenting have proven ineffective as the disease progresses. At Stanford, revascularization procedures are frequently performed for moyamoya, alongside ongoing innovative research.

The team led by Moss Zhao, DPhil, Instructor in Neurosurgery, and senior author Gary Steinberg, MD, PhD, Bernard and Ronni Lacroute-William Randolph Hearst Professor of Neurosurgery and Director of the Stanford Moyamoya Center, published their findings in the Journal of Cerebral Blood Flow & Metabolism.

In their publication, they reported on cerebral blood flow (CBF) and how fast it moves can be a key sign for studying brain health. An MRI technique known as dynamic susceptibility contrast (DSC) is typically used to measure CBF, but is not ideal for children as it requires special contrast agents, which sometimes cause allergic reactions in children. The researchers developed a novel and contrast-free imaging technique known as arterial spin labeling (ASL) to be a non-invasive alternative to both measure CBF and blood transit time at once. Because ASL eliminates the need for contrast agents and radioactive tracers, it reduces medical waste and environmental contamination—making it both patient and planet friendly.

The study enrolled 22 children with moyamoya disease, where researchers compared ASL and DSC MRI results to see how blood flow changed before and after surgeries to improve it. The results showed that after surgery:

• blood flow increased significantly (by 24% with ASL and 7.6% with DSC)
• the time for blood to move through the brain decreased (by 12% with ASL and 15% with DSC)

Overall, the study suggests that revascularization surgeries can improve blood flow in children with moyamoya disease and that ASL is an effective technique for evaluating cerebral blood flow in children, as it does not use radiation.

“We care deeply about our patients’ brain health and long-term quality of life,” Zhao said. “This study really demonstrated our next generation medical imaging technology for brain health without a negative impact on the environment that radiation causes.”

The research team at Stanford University includes individuals from the Department of Neurosurgery, the Maternal and Child Health Research Institute, the Department of Radiology, and the Department of Neurology. Additional team members are Sasha Alexander, Chris Lopez, Helena Zhang, Gabriella Morton, Rui Duarte Armindo, Kristen Yeom, Elizabeth Tong, Bruno Soares, Sarah Lee, and Michael Moseley.