Moyamoya disease (MMD) is a rare cerebrovascular disorder with a biphasic incidence in early childhood and the middle-age of adulthood. Moyamoya syndrome (MMS) refers to the same vasculopathy combined with certain associated diseases such as neurofibromatosis and sickle-cell disease. The pathophysiology involves a gradually progressive stenosis of the terminal internal carotid artery, due to intimal hyperplasia. Autoregulatory distal vasodilation and neovascularization by Moyamoya-associated vessels that by-pass the stenosis may compensate for this to some extent, but the natural history inevitably predisposes for cerebral ischemic and hemorrhagic stroke. Basic medical management can prevent this to some extent by avoiding hypovolemia and hypotension and to administer antiplatelets to reduce thrombogenicity for Moyamoya patients with ischemic rather than hemorrhagic phenotype. However, patients with more severe symptoms and progressive disease require surgical management including direct and indirect revascularization.
Radiological imaging plays a major role in evaluation and follow-up of Moyamoya patients to determine baseline cerebral blood flow (CBF) and the cerebrovascular reserve. Positron emission tomography and magnetic resonance tomography may be used to study more granular aspects of cerebral hemodynamics such as capillary transit time heterogeneity, oxygen extraction fraction, and cerebral oxygen energy metabolism. These may all be used to estimate the risk of deterioration and the optimal time window for surgical intervention.
Nevertheless, there is still a lack of high-quality evidence for the natural history of various MMD/MMS phenotypes, pathophysiological mechanisms, and optimal surgical treatments and time window for intervention. In the current Research Topic, we invite authors to submit manuscripts (original articles, systematic reviews, literature reviews, and mini-reviews) that elaborate on natural history, CBF dynamics, and the optimal time window for surgical interventions in Moyamoya patients as suggested below.
• Diagnostic criteria for MMD and MMS
• Long-term natural history in MMD and MMS in relation to epidemiology, CBF hemodynamics and energy metabolism, stroke, cognition, and health-related quality of life
• Pathophysiological mechanisms in MMD and MMS
• Imaging techniques for evaluation of hemodynamic and metabolic alterations in MMD and MMS
• Effects of medical and surgical interventions on mortality, CBF hemodynamics, stroke/brain atrophy, cognition, and health-related quality of life in the short- and long-term
• Optimization of the time window for surgical interventions, i.e. at what time point/disease-stages are the benefits greater than the risks of treatment
• What more can more be done when the patient is gradually deteriorating despite exhausted surgical interventions? Are there any future therapeutic options nearby?
Moyamoya disease (MMD) is a rare cerebrovascular disorder with a biphasic incidence in early childhood and the middle-age of adulthood. Moyamoya syndrome (MMS) refers to the same vasculopathy combined with certain associated diseases such as neurofibromatosis and sickle-cell disease. The pathophysiology involves a gradually progressive stenosis of the terminal internal carotid artery, due to intimal hyperplasia. Autoregulatory distal vasodilation and neovascularization by Moyamoya-associated vessels that by-pass the stenosis may compensate for this to some extent, but the natural history inevitably predisposes for cerebral ischemic and hemorrhagic stroke. Basic medical management can prevent this to some extent by avoiding hypovolemia and hypotension and to administer antiplatelets to reduce thrombogenicity for Moyamoya patients with ischemic rather than hemorrhagic phenotype. However, patients with more severe symptoms and progressive disease require surgical management including direct and indirect revascularization.
Radiological imaging plays a major role in evaluation and follow-up of Moyamoya patients to determine baseline cerebral blood flow (CBF) and the cerebrovascular reserve. Positron emission tomography and magnetic resonance tomography may be used to study more granular aspects of cerebral hemodynamics such as capillary transit time heterogeneity, oxygen extraction fraction, and cerebral oxygen energy metabolism. These may all be used to estimate the risk of deterioration and the optimal time window for surgical intervention.
Nevertheless, there is still a lack of high-quality evidence for the natural history of various MMD/MMS phenotypes, pathophysiological mechanisms, and optimal surgical treatments and time window for intervention. In the current Research Topic, we invite authors to submit manuscripts (original articles, systematic reviews, literature reviews, and mini-reviews) that elaborate on natural history, CBF dynamics, and the optimal time window for surgical interventions in Moyamoya patients as suggested below.
• Diagnostic criteria for MMD and MMS
• Long-term natural history in MMD and MMS in relation to epidemiology, CBF hemodynamics and energy metabolism, stroke, cognition, and health-related quality of life
• Pathophysiological mechanisms in MMD and MMS
• Imaging techniques for evaluation of hemodynamic and metabolic alterations in MMD and MMS
• Effects of medical and surgical interventions on mortality, CBF hemodynamics, stroke/brain atrophy, cognition, and health-related quality of life in the short- and long-term
• Optimization of the time window for surgical interventions, i.e. at what time point/disease-stages are the benefits greater than the risks of treatment
• What more can more be done when the patient is gradually deteriorating despite exhausted surgical interventions? Are there any future therapeutic options nearby?
