Breakthrough in Stroke Prevention: Cutting-Edge Imaging Technology Identifies High-Risk Patients
by Micaela Harris
November 29, 2023
Moyamoya disease is a rare condition in which blood flow to the brain is limited due to a narrowing of blood vessels, which may result in instances of acute stroke. Although there are several therapeutic procedures that may alleviate these symptoms by a revascularizing of the vessels that help steady the blood flow and supply, studies have shown that many of these invasive procedures result in only temporary relief. The vessels often undergo a re-narrowing - sometimes occurring even as soon as one year post operation.
To evaluate cerebral blood flow and supply post operation, the recommended clinical procedure is dynamic susceptibility contrast MRI, which requires the patient have a catheter inserted. However, an alternative means of measuring cerebral blood flow called arterial spin labeling is a quantitative MRI technique that can noninvasively measure cerebral flow using magnetically labeled blood. Researchers at Stanford University, including Moss Zhao, PhD, Rui Duarte Armindo, MD (visiting scholar from the Western Lisbon Hospital Centre, Portugal), Andrew Gauden, MD, Benjamin Yim, MD, Elizabeth Tong, MD, Michael Moseley, PhD, Gary Steinberg MD, PhD, and Greg Zaharchuk, MD, PhD investigated the possibility of using this technique to survey changes in blood flow in Moyamoya patients, without invasive catheter insertion. The results of their study were recently published in the Journal of Cerebral Blood Flow and Metabolism and featured on the cover of this journal.
Arterial spin labeling with a single post-labeling has been the common approach to cerebral blood flow measurements, however multiple post-labeling delays is a technique that has shown a more thorough measurement of blood flow. The investigators compared arterial spin labeling with single- and multiple post-labeling delays and found that the cerebral blood flow increased due to bypass surgeries with both methods. Less than a year after their surgeries, blood flow increased using both methods in 52 Moyamoya disease patients; however, the effect size was higher with multiple post-labeling delays.
Based on the blood flow data, the investigators conclude that revascularization significantly enhances vascular hemodynamics in Moyamoya patients and multiple post-labeling delay arterial spin labeling may be a preferred means to evaluate cerebral blood for over invasive MRI catheter insertion in patients. This international collaboration was supported by the American Heart Association, the National Institute of Neurological Disorders and Stroke, and the Luso-American Development Foundation.