Physiologic variations in dural venous sinus flow on phase-contrast MR imaging

OBJECTIVE. Our study quantifies normal physiologic variations of dural sinu s flow using phase-contrast MR imaging. SUBJECTS AND METHODS, Fifteen volunteers were imaged using nontriggered and triggered phase-contrast MR venography of the superior sagittal and transv erse sinuses. Triggered scans were obtained during regular breathing, nontr iggered scans were obtained during regular breathing, breath-holding deep i nspiratory breath-holding, and deep expiratory breath-holding. Analysis of variance, Bonferroni method, and Dunn post hoc analysis were used to determ ine any significant differences in the mean flow and velocity between the d ifferent breathing maneuvers. A paired t test was used to compare flow betw een sinuses during regular breathing. RESULTS. Deep inspiratory breath-holding and deep expiratory breath-holding resulted in a significant decrease in blood how and velocity in all dural sinuses compared with regular breathing. During di:ep inspiratory breath-ho lding, blood flow decreased 30.8% in the superior sagittal sinus, 19.7% in the left transverse sinus, and 19.1% in the right transverse sinus. Similar ly, during deep expiratory breath-holding, blood flow decreased 30.2% in th e superior sagittal sinus, 20.8% in the left transverse sinus, and 20.3% in the right transverse sinus. The sum of the flow in the transverse sinuses was significantly greater than in the sagittal sinus. Normal pulsatility of Jural sinus blood velocity was also characterized for all measured sinuses . CONCLUSION. Characterization of variations in dural sinus velocity and Row as a function of the cardiac cycle and breathing maneuvers, using phase-con trast MR imaging, may help separate physiologic from pathologic changes of flow resulting from conditions that influence the cerebrovascular circulati on.