Stenting of Mobile Calcified Emboli After Failed Thrombectomy in Acute Ischemic Stroke: Case Report and Literature Review

BACKGROUND

Mobile calcified emboli are a rare cause of large vessel occlusion and acute ischemic stroke and pose unique challenges to standard mechanical thrombectomy techniques. Intracranial stenting has been reported as a rescue maneuver in cases of failed mechanical thrombectomy owing to dissection or calcified atherosclerotic plaques, but its use for calcified emboli is not well described.

CASE DESCRIPTION

We present 2 cases of acute ischemic stroke caused by mobile calcified emboli. Standard mechanical thrombectomy techniques using aspiration catheters and stent-retrievers failed to remove these emboli, so intracranial stenting was successfully performed in each case, albeit after overcoming unique challenges associated with the stenting of calcified emboli. We also review the literature on intracranial stenting as a salvage therapy for failed mechanical thrombectomy.

CONCLUSIONS

Mobile calcified emboli are rare causes of acute ischemic stroke. Intracranial stenting can be used to successfully treat calcified emboli when mechanical thrombectomy has failed.

Retrospective review of 290 small carotid cave aneurysms over 17 years

OBJECTIVE

The carotid cave is a unique intradural region located along the medial aspect of the internal carotid artery. Small carotid cave aneurysms confined within this space are bound by the carotid sulcus of the sphenoid bone and are thought to have a low risk of rupture or growth. However, there is a lack of data on the natural history of this subset of aneurysms.

METHODS

The authors present a retrospective case series of 290 small (≤ 4 mm) carotid cave aneurysms evaluated and managed at their institution between January 2000 and June 2017.

RESULTS

No patient presented with a subarachnoid hemorrhage attributable to a carotid cave aneurysm, and there were no instances of aneurysm rupture or growth during 911.0 aneurysm-years of clinical follow-up or 726.3 aneurysm-years of imaging follow-up, respectively.

CONCLUSIONS

This series demonstrates the benign nature of small carotid cave aneurysms.

GUide sheath Advancement and aspiRation in the Distal petrocavernous internal carotid artery (GUARD) Technique during Thrombectomy Improves Reperfusion and Clinical Outcomes

BACKGROUND AND PURPOSE

Adjunctive techniques to stent retriever thrombectomy include balloon-guide catheters and/or distal access catheters for aspiration. We describe a novel technique using a flexible, 6 French 088 distal guide sheath advanced past the skull base to augment mechanical thrombectomy. We studied the relative safety and efficacy of this technique in the setting of a combined stent retriever-distal access catheter aspiration thrombectomy protocol.

MATERIALS AND METHODS

We performed a retrospective case-control study of intracranial internal carotid artery or M1-M2 middle cerebral artery occlusions requiring mechanical thrombectomy. Patients were divided into 2 groups based on thrombectomy techniques: conventional stent retriever with distal access catheter aspiration without (standard) and with adjunctive GUide sheath Advancement and aspiRation in the Distal petrocavernous internal carotid artery (GUARD). Using propensity score matching, we compared procedural safety, reperfusion efficacy using the modified Thrombolysis in Cerebral Infarction scale and clinical outcomes with the modified Rankin Scale.

RESULTS

In comparing the GUARD (45 patients) versus standard (45 matched case controls) groups, there were no significant differences in demographics, NIHSS presentations, IV rtPA use, median onset-to-groin puncture times, procedural complications, symptomatic intracranial hemorrhage, or mortality. The GUARD group demonstrated significantly higher successful mTICI ≥2b reperfusion rates (98% versus 80%, P = .015) and improved functional mRS ≤2 outcomes (67% versus 43%, P = .04), with independent effects of the GUARD technique confirmed in a multivariable logistic regression model.

CONCLUSIONS

The GUARD technique during mechanical thrombectomy with combined stent retrieval-distal access catheter aspiration is safe and effective in improving reperfusion and clinical outcomes.

Comparison of Carotid Endarterectomy and Stenting for Symptomatic Internal Carotid Artery Near-Occlusion

BACKGROUND AND PURPOSE

Carotid near-occlusion is defined as severe stenosis of the internal carotid artery with partial or full collapse of the distal vessel wall. The major studies evaluating carotid revascularization excluded patients with carotid near-occlusion. Given the paucity of data in the literature, we attempted to evaluate the safety of carotid endarterectomy and carotid artery stenting in carotid near-occlusion.

MATERIALS AND METHODS

A retrospective data base review was performed from January 2010 to December 2018 to identify patients who underwent carotid endarterectomy or carotid artery stenting for symptomatic ICA near-occlusion and had 1-month clinical and imaging follow-up with carotid sonography. The medical records and imaging studies of patients with ICA near-occlusion were selected for analysis.

RESULTS

Forty-five patients met the criteria for ICA near-occlusion, of whom 39 were included in the study, given insufficient 1-month follow-up on 6 patients. Of the 39 patients, 25 underwent carotid endarterectomy and 14 underwent carotid artery stenting. All patients had technically successful immediate revascularization of the ICA. Most (33 of 39) had 1-year follow-up postoperatively. Patients with carotid artery stenting had 20% restenosis and 79% vessel maturation rates, while patients with carotid endarterectomy had 17.4% restenosis and 84% vessel maturation. There was no significant difference in periprocedural complication rates between the 2 procedures.

CONCLUSIONS

Carotid artery stenting shows similar outcomes in restenosis and vessel maturation rates compared with carotid endarterectomy for ICA near-occlusion. There were no major differences between the 2 treatments in clinical outcomes or periprocedural complications. Carotid artery stenting is a revascularization option for carotid near-occlusion if the patient is considered at high risk for carotid endarterectomy.

Diagnostic Accuracy of High-Resolution Black-Blood MRI in the Evaluation of Intracranial Large-Vessel Arterial Occlusions

BACKGROUND AND PURPOSE

3D high-resolution black-blood MRI or MR vessel wall imaging allows evaluation of the intracranial arterial wall and extraluminal pathology. We investigated the diagnostic accuracy and reliability of black-blood MRI for the intraluminal detection of large-vessel arterial occlusions.

MATERIALS AND METHODS

We retrospectively identified patients with intracranial arterial occlusions, confirmed by CTA or DSA, who also underwent 3D black-blood MRI with nonenhanced and contrast-enhanced T1 sampling perfection with application-optimized contrasts by using different flip angle evolution (T1 SPACE) sequences. Black-blood MRI findings were evaluated by 2 independent and blinded neuroradiologists. Large-vessel intracranial arterial segments were graded on a 3-point scale (grades 0-2) for intraluminal baseline T1 hyperintensity and contrast enhancement. Vessel segments were considered positive for arterial occlusion if focal weak (grade 1) or strong (grade 2) T1-hyperintense signal and/or enhancement replaced the normal intraluminal black-blood signal.

RESULTS

Thirty-one patients with 38 intracranial arterial occlusions were studied. The median time interval between black-blood MRI and CTA/DSA reference standard studies was 2 days (range, 0-20 days). Interobserver agreement was good for T1 hyperintensity (κ = 0.63) and excellent for contrast enhancement (κ = 0.89). High sensitivity (100%) and specificity (99.8%) for intracranial arterial occlusion diagnosis was observed with either intraluminal T1 hyperintensity or contrast-enhancement imaging criteria on black-blood MRI. Strong grade 2 intraluminal enhancement was maintained in >80% of occlusions irrespective of location or chronicity. Relatively increased strong grade 2 intraluminal T1 hyperintensity was noted in chronic/incidental versus acute/subacute occlusions (45.5% versus 12.5%, P = .04).

CONCLUSIONS

Black-blood MRI with or without contrast has high diagnostic accuracy and reliability in evaluating intracranial large-vessel arterial occlusions with near-equivalency to DSA and CTA.

Rapid Development of an Aneurysm at the Anastomotic Site of a Superficial Temporal Artery to Middle Cerebral Artery Bypass: Case Report and Literature Review

BACKGROUND

Direct extracranial to intracranial (EC-IC) bypass is a valuable treatment option for symptomatic occlusive cerebrovascular disease and complex intracranial aneurysms. Aneurysm formation at or near the anastomotic site is a rarely reported phenomenon, and the pathophysiology and appropriate management of such de novo aneurysms are not clear.

CASE DESCRIPTION

Here we present the case of a superficial temporal to middle cerebral artery (STA-MCA) anastomosis that was complicated by aneurysm formation at the anastomotic site. This was treated with microsurgical clipping with preservation of the bypass. Pathologic analysis of the lesion was consistent with a pseudoaneurysm. We provide a literature review of this phenomenon, which is most often associated with low-flow STA-MCA bypasses, including review of the pathologic findings associated with it.

CONCLUSION

Pseudoaneurysm formation at the site of an EC-IC bypass is a rare phenomenon that should be recognized and treated to prevent further growth and rupture.

Standardized Evaluation of Cerebral Arteriovenous Malformations Using Flow Distribution Network Graphs and Dual-venc 4D Flow MRI

BACKGROUND

Cerebral arteriovenous malformations (AVMs) are pathological connections between arteries and veins. Dual-venc 4D flow MRI, an extended 4D flow MRI method with improved velocity dynamic range, provides time-resolved 3D cerebral hemodynamics.

PURPOSE

To optimize dual-venc 4D flow imaging parameters for AVM; to assess the relationship between spatial resolution, acceleration, and flow quantification accuracy; and to introduce and apply the flow distribution network graph (FDNG) paradigm for storing and analyzing complex neurovascular 4D flow data.

STUDY TYPE

Retrospective cohort study.

SUBJECTS/PHANTOM

Scans were performed in a specialized flow phantom: 26 healthy subjects (age 41 ± 17 years) and five AVM patients (age 27-68 years).

FIELD STRENGTH/SEQUENCE

Dual-venc 4D flow with varying spatial resolution and acceleration factors were performed at 3T field strength.

ASSESSMENT

Quantification accuracy was assessed in vitro by direct comparison to measured flow. FDNGs were used to quantify and compare flow, peak velocity (PV), and pulsatility index (PI) between healthy controls with various Circle of Willis (CoW) anatomy and AVM patients.

STATISTICAL TESTS

In vitro measurements were compared to ground truth with Student's t-test. In vivo groups were compared with Wilcoxon rank-sum test and Kruskal-Wallis test.

RESULTS

Flow was overestimated in all in vitro experiments, by an average 7.1 ± 1.4% for all measurement conditions. Error in flow measurement was significantly correlated with number of voxels across the channel (P = 3.11 × 10^-28 ) but not with acceleration factor (P = 0.74). For the venous-arterial PV and PI ratios, a significant difference was found between AVM nidal and extranidal circulation (P = 0.008 and 0.05, respectively), and between AVM nidal and healthy control circulation (P = 0.005 and 0.003, respectively).

DATA CONCLUSION

Dual-venc 4D flow MRI and standardized FDNG analysis might be feasible in clinical applications. Venous-arterial ratios of PV and PI are proposed as network-based biomarkers characterizing AVM nidal hemodynamics.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1718-1730.

Safety and outcome of combined endovascular and surgical management of low grade cerebral arteriovenous malformations in children compared to surgery alone

PURPOSE

To evaluate the outcomes of combined preoperative embolization and microsurgical resection in comparison with microsurgical resection alone as the current standard of care for low-grade cerebral arteriovenous malformations (AVM) in the pediatric population.

MATERIALS & METHODS

We performed a single-center retrospective study of pediatric patients presenting with Spetzler-Martin (SM) grade I and II cerebral AVMs at a high-volume tertiary pediatric hospital between January 2005 and September 2016. Low grade AVM patients were divided into two groups: pre-operative embolization with subsequent microsurgical resection or microsurgical resection alone. Patient demographics, clinical and imaging presentations, AVM morphological characteristics, post-operative complications, and mid to long-term clinical outcomes were studied. Post-embolization and post-surgical outcomes were assessed prior to and after treatment, at 3 months and at final follow-up using the modified Rankin Scale (mRS) to compare both final independent (mRS 0-2) and favorable (no change or improved mRS) clinical outcomes for comparison between study groups. Statistical associations of patient demographics, AVM characteristics/SM grading, and treatment modality group with post-operative complications were performed using univariate logistic regression analysis.

RESULTS

Thirty-four patients with low grade cerebral AVMs met the study inclusion criteria (mean age 10.6 ± 3.4 years; range 3-16 years, 22M:12 F). Twenty patients (59%) presented with ruptured AVMs. Twenty-five patients (73.5%) underwent combined treatment with embolization and microsurgical resection, while 9/34 (26.5%) underwent microsurgical resection alone. A total of 35 embolization procedures performed in 25 patients (Mode, 1; Range, 1-7) were associated with two minor post-embolization and 7 subsequent post-surgical (28%) complications, resulting in clinical deterioration in a single patient. Microsurgical resection alone was associated with 3 post-surgical complications (33%), resulting in permanent neurological disability in a single patient. There was no significance association of post-operative complications with either treatment modality group, combined treatment versus surgical resection alone [OR:1.13; 95% CI:0.23-5.62; p-value 0.88]. SM Grade II and eloquent locations were found to be significantly associated with post-surgical complications of low grade pediatric cerebral AVMs [OR 13.2 and OR 8 respectively, p-value 0.004 and 0.005). On mean follow-up time of 35.7 months, final clinical outcome was favorable in the majority of both treatment arms with no dependent (mRS>2) patients in the combined endovascular and surgical cohort. Two patients in the surgical cohort failed to achieve independent functional status, primarily due to a pre-operative morbid status (p-value 0.015). However, there was no significant difference in favorable outcomes between the treatment groups [p-value 0.14].

CONCLUSION

Our study suggests equivalent safety and favorable clinical outcomes related to combined endovascular embolization and microsurgical resection of low grade pediatric cerebral AVMs in comparison to microsurgical resection alone. On long term clinical follow-up, the vast majority of patients achieved an independent and favorable functional status irrespective of pre-operative embolization.

Abstract WP93: Inter-Operator Heterogeneity in CT/CTP-Guided Patient Selection for Thrombectomy

Introduction: Recent trials have shown application of CTP in identifying patients who will have a favorable response to endovascular reperfusion therapy, in both early and extended time windows after onset of stroke symptoms. However, the optimal imaging protocol to select these patients is still a matter of debate. The purpose of this study was to assess how CTP affects clinical decision making in different time periods after stroke and to investigate the inter-rater agreement in imaging interpretation.

Methods: Imaging sets including non-contrast CT (NCCT) and CTP [RAPID (iSchemaView Inc, Menlo Park, CA)] from patients admitted with the diagnosis of large vessel occlusion (MCA and ICA) stroke at a single institution were retrospectively reviewed by five neurovascular interventionists independently. In order to focus upon the contribution of imaging to decision-making, interventionists were blinded to demographics and clinical symptoms of patients. Images were presented to each interventionist in random fashion, at separate settings (assessing decision-making within 0-6 and 6-24 hrs). Each interventionist was asked whether they would intervene first based upon NCCT, and then after viewing CTP images for the same patient.

Results: Datasets of 38 consecutive patients (female/male: 14/24; mean age: 63.24; side of stroke left/right: 21/17; thrombectomy no/yes: 18/20) were reviewed. Inter-rater agreement was moderate for thrombectomy in both time windows (0-6 hrs: κ = 0.43; 6-24 hrs: κ = 0.50) based on NCCT. Interventionists had overall fair (κ = 0.33) versus moderate agreement (κ = 0.55) for thrombectomy based on CTP in 0-6 hrs versus 6-24 hrs time-windows, respectively. The proportion of times that CTP altered decision-making after viewing NCCT yielded only poor (κ = 0.17) and fair (κ = 0.24) agreement across interventionists in 0-6 and 6-24 hrs time-windows, respectively.

Conclusions: We found heterogeneity in decision-making across neurointerventionists when using the same neuroimaging to determine whether to intervene in acute ischemic stroke, in both the 0-6 and 6-24 hrs time-windows. While overall agreement was higher in 6-24 hrs time window, our data may have important clinical ramifications in standardization of processes of care.

Abstract WMP33: Towards Cerebral Aneurysm Rupture Risk Prediction Using Quantitative Analysis by 4D Flow MRI: Intra-Aneurysmal Vortical Blood Flow and Association to Wall Shear Stress

Introduction: While previous studies have shown a link between changes in aneurysmal wall shear stress (WSS) and risk of rupture, the association between the development of WSS variations and intra-aneurysmal hemodynamic flow patterns remain unknown. Understanding such link could potentially lead to novel early biomarkers for risk stratification of aneurysmal rupture.

Aim: To assess the association between intra-aneurysmal flow patterns behavior and WSS in cerebral aneurysm patients.

Methods: Time-resolved 3D blood flow velocities were acquired by dual-venc 4D flow MRI (kt-GRAPPA R=5, voxel size (1.0x 1.0 x 1.0 mm 3 ), TE/TR 3.5/6.2 ms, temporal resolution 57ms, venc low /venc high 50/100 cm/s) in 12 patients (66 ± 9 years, 8 F), who presented with a total of 14 cerebral aneurysms (average 10-time points per aneurysm synchronized with the cardiac cycle). Time-resolved median WSS was quantified over the 3D aneurysm surface. To quantify 3D blood flow pattern behavior from 4D Flow MRI, we used the fluid dynamics-based helicity metric. Helicity is a signed quantity that measures the strength and alignment between vortical pattern and blood flow directions. Helicity magnitudes take positive values at regions where both vortical pattern and blood flow align in the same direction while regions with opposing directions have negative values. Time-resolved positive and negative helicity were quantified separately by instantaneous volumetric median and correlated with WSS. Correlation was tested using pooled paired data of all acquired time points from all aneurysms (N=147 samples).

Results: (Fig.1) Strong correlations were found between WSS and flow patterns behavior with the strongest correlation (R=0.91, p<0.001) found with negative helicity.

Conclusions: We revealed that intra-aneurismal blood flow pattern behavior strongly correlates with wall shear stress. These results may help in the future to identify early hemodynamic markers for risk of aneurysmal rupture.

Abstract WP114: Incidence and Treatment of Unruptured Brain Aneurysms versus SAH in the United States: Trends and Complications over Two Decades

Introduction: Following publication of ISAT in 2002 showing better outcomes with coiling versus clipping of ruptured aneurysms, there was a substantial increase in endovascular management of ruptured aneurysms. This in turn led to coiling becoming the predominant treatment in both SAH and unruptured aneurysms (UA), as well as an overall increase in volume of aneurysms treated in the USA. However, ISAT did not address UA, and it is unclear if real-world practice trends over the past decade justify this change in both practice pattern and volume.

Methods: National Inpatient Sample datasets from 1993 to 2015 were obtained and data extracted using ICD-9-CM codes for the diagnosis of UA and SAH, and procedural treatments including clipping and coiling. Age-standardized incidence rates of UA and SAH were estimated. Differences in demographics, hospital characteristics and procedure complications by diagnostic groups were examined, and risk ratios were obtained for factors associated with routine discharge and hospital mortality using poisson regression.

Results: From 1993 to 2015, overall treatment of UA significantly increased, yet the incidence of SAH did not change (figure 1). A trend towards increasing procedural complications was noted in SAH, likely related to a concomitant trend observed in increasing patient age and comorbidities. In contrast, recent complication rates of UA repair appeared to plateau or slightly diminish (2011-2015). Clipping of UA remained associated with significantly higher risk ratios for complications when compared with coiling and led to fewer favorable discharges.

Conclusion: We conclude that the age-adjusted incidence of SAH in the United States has remained unchanged throughout the past two decades despite a 3-fold increase in treatment of UA. Modern complication rates of clipping and coiling UA appear relatively stable, with clipping demonstrating significantly higher complication rates and less favorable discharges.

Topographic correlation of infarct area on CT perfusion with functional outcome in acute ischemic stroke

OBJECTIVE

The role of CT perfusion (CTP) in the management of patients with acute ischemic stroke (AIS) remains a matter of debate. The primary aim of this study was to evaluate the correlation between the areas of infarction and penumbra on CTP scans and functional outcome in patients with AIS.

METHODS

This was a retrospective review of 100 consecutively treated patients with acute anterior circulation ischemic stroke who underwent CT angiography (CTA) and CTP at admission between February 2011 and October 2014. On CTP, the volume of ischemic core and penumbra was measured using the Alberta Stroke Program Early CT Score (ASPECTS). CTA findings were also noted, including the site of occlusion and regional leptomeningeal collateral (rLMC) score. Functional outcome was defined by modified Rankin Scale (mRS) score obtained at discharge. Associations of CTP and CTA parameters with mRS scores at discharge were assessed using multivariable proportional odds logistic regression models.

RESULTS

The median age was 67 years (range 19-95 years), and the median NIH Stroke Scale score was 16 (range 2-35). In a multivariable analysis adjusting for potential confounding variables, having an infarct on CTP scans in the following regions was associated with a worse mRS score at discharge: insula ribbon (p = 0.043), perisylvian fissure (p < 0.001), motor strip (p = 0.007), M2 (p < 0.001), and M5 (p = 0.023). A worse mRS score at discharge was more common in patients with a greater volume of infarct core (p = 0.024) and less common in patients with a greater rLMC score (p = 0.004).

CONCLUSIONS

The results of this study provide evidence that several CTP parameters are independent predictors of functional outcome in patients with AIS and have potential to identify those patients most likely to benefit from reperfusion therapy in the treatment of AIS.

Prophylactic Seizure Medication and Health-Related Quality of Life After Intracerebral Hemorrhage

OBJECTIVES

Prophylactic levetiracetam is currently used in ~40% of patients with intracerebral hemorrhage, and the potential impact of levetircetam on health-related quality of life is unknown. We tested the hypothesis that prophylactic levetiracetam is independently associated with differences in cognitive function health-related quality of life.

DESIGN

Patients with intracerebral hemorrhage were enrolled in a prospective cohort study. We performed mixed models for T-scores of health-related quality of life, referenced to the U.S. population at 50 ± 10, accounting for severity of injury and time to follow-up.

SETTING

Academic medical center.

PATIENTS

One-hundred forty-two survivors of intracerebral hemorrhage.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

T-scores of Neuro-Quality of Life Cognitive Function v2.0 was the primary outcome, whereas Neuro-Quality of Life Mobility v1.0 and modified Rankin Scale (a global functional scale) were secondary measures. We prospectively documented if prophylactic levetiracetam was administered and retrieved administration data from the electronic health record. Patients who received prophylactic levetiracetam had worse cognitive function health-related quality of life (T-score 5.1 points lower; p = 0.01) after adjustment for age (p = 0.3), National Institutes of Health Stroke Scale (p < 0.000001), lobar hematoma (p = 0.9), and time of assessment; statistical models controlling for prophylactic levetiracetam and the Intracerebral Hemorrhage Score, a global measure of intracerebral hemorrhage severity, yielded similar results. Lower T-scores of cognitive function health-related quality of life at 3 months were correlated with more total levetiracetam dosage (p = 0.01) and more administered doses of levetiracetam in the hospital (p = 0.03). Patients who received prophylactic levetiracetam were more likely to have a lobar hematoma (27/38 vs 19/104; p < 0.001), undergo electroencephalography monitoring (15/38 vs 21/104; p = 0.02), but not more likely to have clinical seizures (4/38 vs 7/104; p = 0.5). Levetiracetam was not independently associated with the modified Rankin Scale scores or mobility health-related quality of life (p > 0.1).

CONCLUSIONS

Prophylactic levetiracetam was independently associated with lower cognitive function health-related quality of life at follow-up after intracerebral hemorrhage.

Adjunctive Efficacy of Intra-Arterial Conebeam CT Angiography Relative to DSA in the Diagnosis and Surgical Planning of Micro-Arteriovenous Malformations

BACKGROUND AND PURPOSE

Micro-arteriovenous malformations are an underrecognized etiology of intracranial hemorrhage. Our study aimed to assess the adjunctive efficacy of intra-arterial conebeam CTA relative to DSA in the diagnosis and surgical planning of intracranial micro-AVMs.

MATERIALS AND METHODS

We performed a retrospective study of all micro-AVMs (≤1-cm nidus) at our institution. Blinded neuroradiologists qualitatively graded DSA and intra-arterial conebeam CTA images for the detection of specific micro-AVM anatomic parameters (arterial feeder, micronidus, and venous drainer) and defined an overall diagnostic value. Statistical and absolute differences in the overall diagnostic values defined the relative intra-arterial conebeam CTA diagnostic values, respectively. Blinded neurosurgeons reported their treatment approach after DSA and graded the adjunctive value of intra-arterial conebeam CTA to improve or modify treatment. Intra-arterial conebeam CTA efficacy was defined as interobserver agreement in the relative intra-arterial conebeam CTA diagnostic and/or treatment-planning value scores.

RESULTS

Ten patients with micro-AVMs presented with neurologic deficits and/or intracranial hemorrhages. Both neuroradiologists assigned a higher overall intra-arterial conebeam CTA diagnostic value (P < .05), secondary to improved evaluation of both arterial feeders and the micronidus, with good interobserver agreement (τ = 0.66, P = .018) in the relative intra-arterial conebeam CTA diagnostic value. Both neurosurgeons reported that integrating the intra-arterial conebeam CTA data into their treatment plan would allow more confident localization for surgical/radiation treatment (8/10; altering the treatment plan in 1 patient), with good interobserver agreement in the relative intra-arterial conebeam CTA treatment planning value (τ = 0.73, P = .025).

CONCLUSIONS

Adjunctive intra-arterial conebeam CTA techniques are more effective in the diagnostic identification and anatomic delineation of micro-AVMs, relative to DSA alone, with the potential to improve microsurgical or radiosurgery treatment planning.

Hydrophilic polymer embolic complication during diagnostic cerebral angiography presenting with delayed intracranial hemorrhage: case report and literature review

We report two serial neuroendovascular cases of hydrophilic polymer embolic complications, and highlight a unique case of a routine diagnostic cerebral angiogram that was complicated by delayed intracranial hemorrhage requiring surgical decompression. Histopathology specimens revealed organized intravascular thrombi with foci of non-polarizable, basophilic foreign material. Shavings from the hydrophilic coatings of a standard diagnostic catheter and guidewire share histologic characteristics with this intravascular foreign material, confirming the diagnosis of hydrophilic polymer emboli. While this phenomenon has been described for complex neurointerventional procedures, it is rare with routine diagnostic cerebral angiography. Along with a detailed literature review, these cases provides further evidence that even basic hydrophilic coated catheters and/or wires may contribute to the etiology of iatrogenic emboli in the neurovasculature with the potential for acute and subacute complications, requiring further investigation.

MynxGrip vascular closure device use in pediatric neurointerventional procedures

OBJECTIVE The aim of this paper was assess the efficacy and safety of using the MynxGrip arterial closure device in pediatric neuroendovascular procedures where the use of closure devices remains off-label despite their validation and widespread use in adults. METHODS A retrospective review of all pediatric patients who underwent diagnostic or interventional neuroendovascular procedures at the authors' institution was performed. MynxGrip use was predicated by an adequate depth of subcutaneous tissue and common femoral artery (CFA) diameter. Patients remained on supine bedrest for 2 hours after diagnostic procedures and for 3 hours after therapeutic procedures. Patient demographics, procedural details, hemostasis status, and complications were recorded. RESULTS Over 36 months, 83 MynxGrip devices were deployed in 53 patients (23 male and 30 female patients; mean age 14 years) who underwent neuroendovascular procedures. The right-side CFA was the main point of access for most procedures. The mean CFA diameter was 6.24 mm and ranged from 4 mm to 8.5 mm. Diagnostic angiography comprised 46% of the procedures. A single device failure occurred without any sequelae; the device was extracted, and hemostasis was achieved by manual compression with the placement of a Safeguard compression device. No other immediate or delayed major complications were recorded. CONCLUSIONS MynxGrip can be used safely in the pediatric population for effective hemostasis and has the advantage of earlier mobilization.

Seeing Floaters: A Case Report and Literature Review of Intraventricular Migration of Silicone Oil Tamponade Material for Retinal Detachment

BACKGROUND

Intraocular injection of silicone oil is commonly performed during vitrectomy to tamponade the retina in place for treatment of retinal detachment. Although rare, this intravitreal silicone can migrate through the optic nerve and chiasm and enter the cerebral ventricles.

CASE DESCRIPTION

Here we present a case report of a patient presenting with headache and intraventricular hyperdensities on a computed tomography (CT) scan, raising a concern for intraventricular hemorrhage. However, the intraventricular hyperdensities were in a nondependent location and moved to a new nondependent location when repeat imaging was performed with the patient in the prone position. We provide a literature review of this phenomenon and discuss the relevant CT and magnetic resonance imaging findings.

CONCLUSIONS

Intraocular silicone can rarely migrate into the cerebral ventricular system. Careful review of the clinical history and imaging findings can help distinguish this from other, more dangerous intracranial pathologies.

Magnesium, hemostasis, and outcomes in patients with intracerebral hemorrhage

OBJECTIVE

We tested the hypothesis that admission serum magnesium levels are associated with hematoma volume, hematoma growth, and functional outcomes in patients with intracerebral hemorrhage (ICH).

METHODS

Patients presenting with spontaneous ICH were enrolled in an observational cohort study that prospectively collected demographic, clinical, laboratory, radiographic, and outcome data. We performed univariate and adjusted multivariate analyses to assess for associations between serum magnesium levels and initial hematoma volume, final hematoma volume, and in-hospital hematoma growth as radiographic measures of hemostasis, and functional outcome measured by the modified Rankin Scale (mRS) at 3 months.

RESULTS

We included 290 patients for analysis. Admission serum magnesium was 2.0 ± 0.3 mg/dL. Lower admission magnesium levels were associated with larger initial hematoma volumes on univariate (p = 0.02), parsimoniously adjusted (p = 0.002), and fully adjusted models (p = 0.006), as well as greater hematoma growth (p = 0.004, p = 0.005, and p = 0.008, respectively) and larger final hematoma volumes (p = 0.02, p = 0.001, and p = 0.002, respectively). Lower admission magnesium level was associated with worse functional outcomes at 3 months (i.e., higher mRS; odds ratio 0.14, 95% confidence interval 0.03-0.64, p = 0.011) after adjustment for age, admission Glasgow Coma Scale score, initial hematoma volume, time from symptom onset to initial CT, and hematoma growth, with evidence that the effect of magnesium is mediated through hematoma growth.

CONCLUSIONS

These data support the hypothesis that magnesium exerts a clinically meaningful influence on hemostasis in patients with ICH.

Intradural extramedullary cavernous malformation with extensive superficial siderosis of the neuraxis: Case report and review of literature

Background:

Spinal cavernous malformations usually affect the vertebral bodies and are seldom intradural. Here, we report a rare spinal intradural-extramedullary cavernous malformation associated with extensive superficial siderosis along the neuraxis in a patient with radicular complaints.

Case Description:

A 60-year-old male presented with subacute headaches, intermittent fever, and acute back and radicular leg pain for 1–2 weeks. Magnetic resonance imaging revealed an intradural-extramedullary lesion just below the conus medullaris (at the L2 level). There was associated subarachnoid hemorrhage in the lumbar cistern and superficial siderosis along the entire spinal neuraxis. Following surgical resection, the patient's symptoms resolved. Histopathology of the lesion was of a cavernous malformation.

Conclusions:

There are only 56 cases of spinal intradural-extramedullary cavernous malformations published in the literature; however, only 3 described superficial neuraxis siderosis as noted in this case. In the present case, slowly recurring hemorrhages of the lesion located at the conus likely contributed to the complete neuraxis superficial siderosis. Timely evaluation and treatment of these lesions is warranted to avoid further compressive and/or hemorrhagic complications.

Systematic Review of Safety and Cost-Effectiveness of Venous Thromboembolism Prophylaxis Strategies in Patients Undergoing Craniotomy for Brain Tumor

BACKGROUND

Studies have evaluated various strategies to prevent venous thromboembolism (VTE) in neuro-oncology patients, without consensus.

OBJECTIVE

To perform a systematic review with cost-effectiveness analysis (CEA) of various prophylaxis strategies in tumor patients undergoing craniotomy to determine the safest and most cost-effective prophylaxis regimen.

METHODS

A literature search was conducted for VTE prophylaxis in brain tumor patients. Articles reporting the type of surgery, choice of VTE prophylaxis, and outcomes were included. Safety of prophylaxis strategies was determined by measuring rates of VTE and intracranial hemorrhage. Cost estimates were collected based on institutional data and existing literature. CEA was performed at 30 d after craniotomy, comparing the following strategies: mechanical prophylaxis (MP), low molecular weight heparin with MP (MP+LMWH), and unfractionated heparin with MP (MP+UFH) to prevent symptomatic VTE. All costs were reported in 2016 US dollars.

RESULTS

A total of 34 studies were reviewed (8 studies evaluated LMWH, 12 for MP, and 7 for UFH individually or in combination; 4 studies used LMWH and UFH preoperatively). Overall probability of VTE was 1.49% (95% confidence interval (CI) 0.42-3.72) for MP+UFH, 2.72% [95% CI 1.23-5.15] for MP+LMWH, and 2.59% (95% CI 1.31-4.58) for MP, which were not statistically significant. Compared to a control of MP alone, the number needed to treat for MP+UFH is 91 and 769 for MP+LMWH. The risk of intracranial hemorrhage was 0.26% (95% CI 0.01-1.34) for MP, 0.74% (95% CI 0.09-2.61) for MP+UFH, and 2.72% (95% CI 1.23-5.15) for MP+LMWH, which were also not statistically significant. Compared to MP, the number needed to harm for MP+UFH was 208 and for MP+LMWH was 41. Fifteen studies were included in the final CEA. The estimated cost of treatment was $127.47 for MP, $142.20 for MP+UFH, and $169.40 for MP+LMWH. The average cost per quality-adjusted life-year for different strategies was $284.14 for MP+UFH, $338.39 for MP, and $722.87 for MP+LMWH.

CONCLUSION

Although MP+LMWH is frequently considered the optimal prophylaxis for VTE risk reduction, our model suggests that MP+UFH is the safest and most cost-effective measure to balance VTE and hemorrhage risks in brain tumor patients at lower risk of hemorrhage. MP+LMWH may be more effective for patients at higher risk of VTE.

Abstract TP258: Large Vessel Occlusion Screening Tool for Acute Ischemic Stroke Patients

Introduction: With randomized data proving the benefit of endovascular therapy for large vessel occlusion (LVO), there is increasing interest in developing a rapid screening tool to predict LVO in acute ischemic stroke (AIS) patients in the emergency department (ED) setting.

Methods: We implemented a new LVO screening tool in our ED in March 2016. The LVO score ranged from 0-6 and included one point for each of the following individual components: level of consciousness, gaze deviation, aphasia, dysarthria, facial droop, and arm weakness. LVO was defined as an intracranial occlusion of the internal carotid artery, M1 and M2 segments of the middle cerebral artery, A1 and A2 segments of the anterior cerebral artery, P1 and P2 segments of the posterior cerebral artery, basilar artery, or vertebral arteries. We calculated c-statistics to determine the discrimination of the LVO score for presence of LVO on emergent vascular imaging and identified the optimal cut-off score with maximum sensitivity and specificity.

Results: Among 65 consecutive confirmed AIS patients between March and July 2016, 63.1% had a positive LVO screen (score > 0); 97% of the patients underwent emergent CT angiography. Eleven (16.9%) patients had an LVO in the territory of ischemic infarct, 10 of which were in the anterior circulation. The LVO score had a c-statistic of 0.77 (95%CI 0.59-0.96, p< 0.005) for predicting LVO. An optimal cut-off score > 2 was present in 19 patients (29.2%) and was associated with 72.7% sensitivity and 79.6% specificity; positive and negative predictive values were 42.1% and 93.5%, respectively.

Conclusions: In a preliminary analysis, a simple LVO screening tool had acceptable discrimination for predicting LVO in AIS patients in the ED. Further validation and refinement of the tool is necessary.

Emergent Endovascular Management of Long-Segment and Flow-Limiting Carotid Artery Dissections in Acute Ischemic Stroke Intervention with Multiple Tandem Stents

BACKGROUND AND PURPOSE

Although most cervical dissections are managed medically, emergent endovascular treatment may become necessary in the presence of intracranial large-vessel occlusions, flow-limiting and long-segment dissections with impending occlusion, and/or hypoperfusion-related ischemia at risk of infarction. We investigated the role of emergent endovascular stenting of long-segment carotid dissections in the acute ischemic stroke setting.

MATERIALS AND METHODS

We retrospectively studied long-segment carotid dissections requiring stent reconstruction with multiple tandem stents (≥3 stents) and presenting with acute (<12 hours) ischemic stroke symptoms (NIHSS score, ≥4). We analyzed patient demographics, vascular risk factors, clinical presentations, imaging/angiographic findings, technical procedures/complications, and clinical outcomes.

RESULTS

Fifteen patients (mean age, 51.5 years) with acute ischemic stroke (mean NIHSS score, 15) underwent endovascular stent reconstruction for vessel and/or ischemic tissue salvage. All carotid dissections presented with >70% flow limiting stenosis and involved the distal cervical ICA with a minimum length of 3.5 cm. Carotid stent reconstruction was successful in all patients with no residual stenosis or flow limitation. Nine patients (60%) harbored intracranial occlusions, and 6 patients (40%) required intra-arterial thrombolysis/thrombectomy, achieving 100% TICI 2b-3 reperfusion. Two procedural complications were limited to thromboembolic infarcts from in-stent thrombus and asymptomatic hemorrhagic infarct transformation (7% morbidity, 0% mortality). Angiographic and ultrasound follow-up confirmed normal carotid caliber and stent patency, with 2 cases of <20% in-stent stenosis. Early clinical improvement resulted in a mean discharge NIHSS score of 6, and 9/15 (60%) patients achieved a 90-day mRS of ≤2.

CONCLUSIONS

Emergent stent reconstruction of long-segment and flow-limiting carotid dissections in acute ischemic stroke intervention is safe and effective, with favorable clinical outcomes, allowing successful thrombectomy, vessel salvage, restoration of cerebral perfusion, and/or prevention of recurrent thromboembolic stroke.

Subjective and objective evaluation of image quality in biplane cerebral digital subtraction angiography following significant acquisition dose reduction in a clinical setting

OBJECTIVE

Different technical and procedural methods have been introduced to develop low radiation dose protocols in neurointerventional examinations. We investigated the feasibility of minimizing radiation exposure dose by simply decreasing the detector dose during cerebral DSA and evaluated the comparative level of image quality using both subjective and objective methods.

METHODS

In a prospective study of patients undergoing diagnostic cerebral DSA, randomly selected vertebral arteries (VA) and/or internal carotid arteries and their contralateral equivalent arteries were injected. Detector dose of 3.6 and 1.2 μGy/frame were selected to acquire standard dose (SD) and low dose (LD) images, respectively. Subjective image quality assessment was performed by two neurointerventionalists using a 5 point scale. For objective image quality evaluation, circle of Willis vessels were categorized into conducting, primary, secondary, and side branch vessels. Two blinded observers performed arterial diameter measurements in each category. Only image series obtained from VA injections opacifying the identical posterior intracranial circulation were utilized for objective assessment.

RESULTS

No significant difference between SD and LD images was observed in subjective and objective image quality assessment in 22 image series obtained from 10 patients. Mean reference air kerma and kerma area product were significantly reduced by 61.28% and 61.24% in the LD protocol, respectively.

CONCLUSIONS

Our study highlights the necessity for reconsidering radiation dose protocols in neurointerventional procedures, especially at the level of baseline factory settings.