In our previous blogs, we discussed ASL MRI to image abnormal blood vessels in Moyamoya patients. We looked at a study that compared MRI and PET images of normal and healthy people. In this blog, we will look at the application of ASL MRI on adult Moyamoya patients.
According to the latest study by Dr. Moss Zhao (AHA Postdoctoral Fellow, 2021), ASL MRI can detect impaired blood flow and circulation in Moyamoya patients without any radiation or contrast agents.
In this study, Dr. Zhao’s team enrolled nearly 30 adult Moyamoya patients without acute stroke or tissue infarcts in the brain. They scanned the brain of these patients using the advanced ASL MRI technique (multi-delay ASL) that were tested successfully on normal and healthy people before. Similar to the study designed in the previous blog, Dr. Zhao’s team collected both ASL and PET images from the Moyamoya patients at the same time before these patients underwent their bypass surgery. The results from this study were convincing that ASL can replace PET to characterize the pathophysiology of Moyamoya disease patients. The image in this blog shows the vessel occlusion and its impact on blood flow in a Moyamoya patient.
Another advantage of ASL is the elimination of contrast agents. In many MRI exams, patients need to receive a contrast agent (such as gadolinium) to enhance the image quality. However, the contrast agent can cause side effects and deposit in the brain. Although there is no evidence suggesting its impact on health, we should minimize the use of these contrast agents. In the same study, Dr. Zhao’s team also demonstrated that the advanced ASL can create images without contrast agents and that doctors favored the new ASL technique over the conventional contrast-based imaging method.
Taken together, ASL MRI will become more accessible to radiologists to diagnose Moyamoya disease without causing side effects to patients. The technique will allow safe, affordable, and fast for imaging to identify patients with a higher risk for stroke.
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Dr. Moss Zhao is an AHA Postdoctoral Fellow at Stanford University. His research interests include developing advanced and clinically viable imaging technologies for cerebrovascular diseases and characterizing the metabolic demands in the first two decades of human brain development. He is passionate about science communication and public engagement.