Moyamoya is a rare blood vessel condition that has an outsized impact on children, as it is responsible for about 6 percent of pediatric strokes in the United States. Surgical revascularization is the only treatment and is very effective. However, clinicians face challenges in identifying new or worsening disease before a disabling stroke occurs, predicting optimal timing for surgical intervention, and tailoring treatment to individual patients. These challenges are further exacerbated in children, who may not be able to articulate symptoms clearly or tolerate the detailed imaging tests commonly used in adult patients.