Abstract WP168: Cerebrovascular Reactivity Predicts Surgical Decisions in Moyamoya Patients

Introduction: Moyamoya disease (MMD) is characterized by chronic occlusion of the distal intracranial internal carotid arteries and can be treated by revascularization surgery. At present, surgical decisions are primarily based on symptomatology and imaging studies using DSA and SPECT, which are are costly, invasive, time consuming and qualitative. Here we applied a novel iVas-MRI technique that provides quantitative assessment of multiple hemodynamic parameters in a 9-minute scan in MMD patients, and evaluated the ability of iVas parametric maps to predict surgical decisions in such patients. Methods: Sixteen MMD patients were scanned on 3T MRI. Each patient had at least one hemisphere pending decision regarding surgery at the time of MRI. During iVas-MRI, a concomitant CO2/O2 breathing challenge was performed while BOLD images were continuously collected. BOLD images and end-tidal (Et) CO2 and O2 traces were used to calculate maps of cerebrovascular reactivity (CVR, based on BOLD signal change to EtCO2 change), cerebral blood volume (CBV, based on BOLD signal change to EtO2 change), and bolus arrival time (BAT, based on the time lag between EtCO2/O2 and BOLD signal). Parametric values from the ICA perfusion territory were compared between two groups, surgical and medical, with decision made by the treating neurosurgeons blinded to research data. The area-under-the-ROC-curve (AUC) was calculated to evaluate the performance of the MRI indices in predicting surgical decisions. Results: Out of the 23 hemispheres under consideration, 9 were diagnosed as surgical and 14 considered medical. CVR, CO2-BAT and O2-BAT values showed significant differences between the two groups (p=0.0002, 0.005 and 0.001, respectively), while CBV values showed no difference (p=0.45). Brain hemispheres that required revascularization surgeries had lower CVR and longer BAT, compared to medically-managed hemispheres. ROC analyses revealed an AUC of 0.89, 0.84 and 0.95 for CVR, O2-BAT, and CO2-BAT respectively. Conclusion: Our results showed that CVR and BAT had a great accuracy in predicting surgical decisions. Therefore, iVas-MRI may be a cost-effective and reliable method to select between medical and surgical treatments for MMD patients.