Diagnostic Criteria for Moyamoya Disease - 2021 Revised Version

In this report, we, the Research Committee on Moyamoya Disease (Spontaneous Occlusion of the circle of Willis), describe in detail the changes in the new "Diagnostic Criteria 2021" for moyamoya disease and its scientific basis to make it widely known to the world. The revised criteria cover all aspects of the disease, including a definition of the disease concept, diagnostic imaging, and the concept of quasi-moyamoya disease (moyamoya syndrome).