Objective:

To evaluate the relationship between Suzuki stage and CVR in patients with Moyamoya.

Background:

Digital subtraction angiography (DSA) is considered the gold standard for the diagnosis and monitoring of Moyamoya disease, and Suzuki staging is widely used to assess the severity of Moyamoya. However, DSA is an invasive procedure, and Suzuki staging relies on an ordinal scale with limited sensitivity for tracking disease progression or evaluating the response to extracranial-intracranial (EC-IC) bypass treatment. Cerebrovascular reactivity (CVR) is a noninvasive quantitative measurement of vascular reserve with high sensitivity and reproducibility. We hypothesize that Suzuki stage is correlated with CVR and it may serve as a biomarker for disease assessment and monitoring disease.

Design/Methods:

In a single-center study, 20 consecutive patients (involving 30 brain hemispheres) with angiographically confirmed Moyamoya were identified. The severity of Moyamoya was assessed using a Suzuki score and categorized as mild (1-2), moderate (3-4), or severe (5-6). CVR was measured as the ratio of the blood-oxygen-level-dependent (BOLD) magnetic resonance signal response divided by an unit increase in regulated end-tidal carbon dioxide (ΔBOLD/ΔPetPCO2). Multivariable regression analyses were performed to evaluate the linear relationship between Suzuki staging and CVR. 

Results:

Median age was 50 years (range 23-70), 55% were women. The distribution of Suzuki stages was as follows: mild 5 (16.7%), moderate 15 (50.0%), severe 10 (33.3%). Mean CVR decreased with increasing severity of Suzuki stage (mild: 0.12 ± 0.04, moderate: 0.07 ± 0.04, severe: 0.04 ± 0.03, p=0.007). There was an inverse dose-dependent relationship between CVR and Suzuki score for moyamoya severity (Pearson correlation coefficient -0.15; P=0.004). This correlation persisted even after adjustments for age and comorbidities (adjusted beta-coefficient -0.04; P=0.025).

Conclusions:

CVR is independently correlated with Suzuki staging in assessing the severity of Moyamoya disease, suggesting that CVR may serve as a biomarker to quantify Moyamoya collaterals for disease progression and monitoring.