Collateral Circulation in Moyamoya Disease: A New Grading System.

Area of Science:

• Neurology
• Radiology
• Vascular Surgery

Background:

• Moyamoya disease (MMD) necessitates accurate stroke risk prediction and intervention guidance.
• Current grading systems may not fully capture the nuances of collateral circulation in MMD.

Purpose of the Study:

• To evaluate a novel grading system for MMD based on collateral circulation and Suzuki stage.
• To assess the system's ability to predict clinical symptoms, hemodynamic status, and prognosis.

Main Methods:

• Retrospective analysis of 301 idiopathic MMD patients (2014-2016).
• Development of a 1-12 point collateral circulation grading system incorporating pial, perforator, and internal cerebral artery flow, linked to Suzuki stages.
• Evaluation of hemodynamic status using dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI).

Main Results:

• Lower collateral scores (<8) correlated with infarction and intraparenchymal hemorrhage.
• Higher scores (>8) were associated with transient ischemic attack, headache, and intraventricular hemorrhage.
• Lower scores correlated with more severe DSC-MRI findings (time to peak delay, reduced cerebral blood volume and flow ratios) and worse postoperative prognosis.

Conclusions:

• The novel MMD collateral grading system demonstrates strong correlation with clinical symptoms and hemodynamic status.
• This system shows potential for improved risk stratification and prognosis prediction in Moyamoya disease patients.
• The grading system may aid in guiding therapeutic interventions and managing patient outcomes.