Quantitative normalized signal intensity measurements.

Quantitative normalized signal intensity measurements were performed by region-of-interest (ROI) analysis. Vessel-tissue contrast ratio of the confluence of sinuses (CoS) and . middle cerebral artery (MCA) were assessed in correlation to surrounding gray matter (GM). Therefore, ROI were placed in the largest diameter of the CoS and proximal left M1 segments as well as adjacent gray matter . The average diameter for the ROI of the CoS was 8–12 mm; the ROI for MCA was 3–5 mm in diameter; the ROI for brain parenchyma amounted to approximately 10 mm. In surgically treated Moyamoya patients ROI were placed in the superficial temporal artery to middle cerebral artery bypass instead of the proximal M1 segment. AVM: arteriovenous malformation AVF: dural arteriovenous fistula. CoS: confluence of sinuses SSS: superior sagittal sinus. GM: gray matter MCA: middle cerebral artery M1 segment. Quantitative normalized signal intensity measurements.