Quantitative Magnetic Resonance Venography is Correlated With Intravenous Pressures Before and After Venous Sinus Stenting: Implications for Treatment and Monitoring.

BACKGROUND: Endovascular stenting is an effective treatment for patients with clinically significant cerebral venous sinus stenosis. Traditionally, stenting is indicated in elevated intravenous pressures on conventional venography; however, noninvasive monitoring is more desirable. Quantitative magnetic resonance angiography is an imaging modality that measures blood flow noninvasively. Established in the arterial system, applications to the venous sinuses have been limited.
OBJECTIVE: To examine quantitative magnetic resonance venography (qMRV) in the measurement of venous sinus flow in patients undergoing endovascular stenting and to identify a relationship with intravenous pressures.
METHODS: Five patients with intracranial hypertension secondary to venous sinus stenosis underwent cerebral venous stenting between 2009 and 2013 at a single institution. Preoperatively, venous sinus flow was determined by using qMRV, and intravenous pressure was measured during venography. After stenting, intravenous pressure, qMRV flow, and clinical outcomes were assessed and compared.
RESULTS: A mean prestenotic intravenous pressure of 45.2 mm Hg was recorded before stenting, which decreased to 27.4 mm Hg afterward (Wilcoxon signed rank test P = .04). Total jugular outflow on qMRV increased by 260.2 mL/min. Analysis of the change in intravenous pressure and qMRV flow identified a linear relationship (Pearson correlation r = 0.926). All patients displayed visual improvement at 6 weeks.
CONCLUSION: Venous outflow by qMRV increases after endovascular stenting and correlates with significantly improved intravenous pressures. These findings introduce qMRV as a potential adjunct to measure venous flow after stenting, and as a plausible tool in the selection and postoperative surveillance of the patient who has cerebral venous sinus stenosis.