The Bihemispheric Posterior Interior Cerebellar Artery: Anatomic Variations and Clinical Relevance in 11 Cases.

PURPOSE: Although the anatomic course of the posterior interior cerebellar artery (PICA) is variable, it is thought to be very rare for the artery to cross midline, with an estimated incidence of 0.1%. Bihemispheric PICA crosses midline and typically serves both PICA territories. METHODS: We present 11 cases of bihemispheric PICA discovered from retrospective angiogram review, the largest to date reported in the literature. RESULTS: Five cases were the typical bihemispheric PICA pattern, three were bihemispheric with distal vertebral hypoplasia, two cases were the vermian type, and one was atypical, with the PICA feeding a contralateral cerebellar arteriovenous malformation (AVM). The branching point to the contralateral hemisphere always occurred distal to the ascending tonsillar loop and all true bihemispheric variants had contralateral PICA aplasia. CONCLUSIONS: The true incidence of this variant may be much higher than previously thought (3.6% in the current series), and has relevance for cerebrovascular disease, including aneurysm, AVM, and ischemic stroke. Neuroradiologists, neurologists, and neurosurgeons should be aware of this potential variant

Endovascular Approach and Technique for Treatment of TransverseSigmoid Dural Arteriovenous Fistula with Cortical Reflux: The Importance of Venous Sinus Sacrifice

Introduction: Treatment of dural arteriovenous fistula involving the transverse‐igmoid region with cortical reflux is complex; treatment options may require s sacrifice of the fistulous segment of sinus. Methods: We reviewed cases of endovascular sinus sacrifice for dural fistulae at our nstitution from 2007‐2012. Demographic, decision‐making, technical, and outcome i data were collected. Results: Seven patients were identified who underwent endovascular sinus sacrifice for treatment of dural fistula during this 4 year period. Determination of the fistulous sinus segment was based on the pattern of cortical venous drainage. Endovascular access to the sinus was achieved trans‐arterial, transvenous, or via open surgery in one case. Complete cure of the target fistula was obtained in all cases. One patient had transient post‐procedure headache. There were no emorrhages, new neurological deficits, or sign of increased intracranial pressure. h 6/7 patients had angiographic follow up at least 6 months with no recurrence. Conclusion: Fistulas of the transverse‐sigmoid sinuses with cortical reflux may require sacrifice of the parent sinus for cure. Defining the fistulous segment and occluding this segment deliberately, completely and precisely is essential for cure. Several modalities and approaches can be used to achieve this. For properly selected patients, cure of the lesions can be achieved with this method with low risk of morbidity

Detection of Intracranial In-Stent Restenosis Using Quantitative Magnetic Resonance Angiography

BACKGROUND AND PURPOSE: In-stent restenosis (ISR) after angioplasty/stenting for intracranial stenosis has been reported in up to 25% to 30% of patients. Detection and monitoring of ISR relies primarily on serial catheter angiography, because noninvasive imaging methods are typically hampered by stent-related artifact. We examined the value of serial vessel flow measurements using quantitative magnetic resonance angiography (QMRA) in detection of ISR. Material and METHODS: Records of patients undergoing stenting for intracranial symptomatic stenosis >50% between 2005 and 2009 were retrospectively reviewed. Angiographic images were graded by a blinded neurointerventionalist for stenosis pretreatment, immediately after treatment, and during follow-up. Flow in the affected vessel measured by QMRA was recorded; > 25% reduction in flow was considered indicative of an adverse change. Clinical data regarding neurological outcome were also collected. RESULTS: Twenty-eight patients underwent stenting during the time interval studied. Of these, 12 patients (mean age, 55.5 years; 8 female) had contemporaneous angiography and QMRA and were analyzed. Median follow-up was 9 months. Six patients (50%) demonstrated angiographic restenosis 2 to 12 months after treatment; all had an analogous decrease in flow in the vessel of interest. Of 3 patients with more severe flow decrement (> 50%), 2 experienced stroke. None of the patients without angiographic ISR demonstrated a flow decrease on QMRA. CONCLUSIONS: In this preliminary series, flow decrease on QMRA is highly predictive of angiographic ISR. Additionally, the degree of flow decrement correlates with symptomatic ISR. QMRA may provide a useful noninvasive tool for serial monitoring after intracranial stenting

Detection of Intracranial In-Stent Restenosis Using Quantitative Magnetic Resonance Angiography

BACKGROUND AND PURPOSE: In-stent restenosis (ISR) after angioplasty/stenting for intracranial stenosis has been reported in up to 25% to 30% of patients. Detection and monitoring of ISR relies primarily on serial catheter angiography, because noninvasive imaging methods are typically hampered by stent-related artifact. We examined the value of serial vessel flow measurements using quantitative magnetic resonance angiography (QMRA) in detection of ISR. Material and METHODS: Records of patients undergoing stenting for intracranial symptomatic stenosis >50% between 2005 and 2009 were retrospectively reviewed. Angiographic images were graded by a blinded neurointerventionalist for stenosis pretreatment, immediately after treatment, and during follow-up. Flow in the affected vessel measured by QMRA was recorded; > 25% reduction in flow was considered indicative of an adverse change. Clinical data regarding neurological outcome were also collected. RESULTS: Twenty-eight patients underwent stenting during the time interval studied. Of these, 12 patients (mean age, 55.5 years; 8 female) had contemporaneous angiography and QMRA and were analyzed. Median follow-up was 9 months. Six patients (50%) demonstrated angiographic restenosis 2 to 12 months after treatment; all had an analogous decrease in flow in the vessel of interest. Of 3 patients with more severe flow decrement (> 50%), 2 experienced stroke. None of the patients without angiographic ISR demonstrated a flow decrease on QMRA. CONCLUSIONS: In this preliminary series, flow decrease on QMRA is highly predictive of angiographic ISR. Additionally, the degree of flow decrement correlates with symptomatic ISR. QMRA may provide a useful noninvasive tool for serial monitoring after intracranial stenting

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

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