Primary Central Nervous System Lymphoma Presenting as Isolated Multiple Cranial Neuropathies: An Extremely Rare Case

Primary central nervous system lymphoma (PCNSL) is an uncommon malignancy of B-cell origin that typically involves the brain, eyes, and spinal cord without systemic spread. PCNSL typically involves the cerebral hemispheres, basal ganglia, or periventricular region. Isolated leptomeningeal PCNSL without any evidence of parenchymal involvement is very rare. We present a very unusual case of PCNSL presenting as persistent bilateral Bell's palsy and trigeminal neuralgia with magnetic resonance imaging (MRI) brain showing significantly hypertrophied enhancing bilateral facial and trigeminal nerves.

Retrieval of Migrated Coils From Distal Cerebral Vasculature Using Stent Retriever: A Case Series

The incidence of coil dislocation during an endovascular embolization of intracranial aneurysm is low but it can lead to serious thrombo-embolic complications. Therefore, coil displacement/migration often requires either retrieval or fixation of the errant coil with a stent. There are no standard recommended methods of coil retrieval. We present a series of three cases in which off-label application of a stent retriever allowed successful retrieval of herniated coils.

A Novel Case of Deep Temporal Artery (DTA) Embolization for Recurrent Subacute-Chronic Subdural Hematoma

Subdural hemorrhage (SDH) is a common neurological disease. In past, SDHs were managed either conservatively (non-surgically) or with surgical evacuation (burr hole versus craniotomy) depending on the severity. Surgical evacuation has major challenges including high recurrence rate, stoppage and reversal of antiplatelet or anticoagulation agents, risk of general anesthesia and surgery in elderly patients with multiple comorbidities. Given the above challenges, embolization of the distal branches of the middle meningeal artery (MMA) has recently emerged as an excellent alternate to surgical evacuation or conservative management. To the best of our knowledge, there is no literature on the embolization of the deep temporal artery (DTA) for subacute-chronic SDH. We report the first case of recurrent subdural hematoma post MMA embolization that was successfully treated with embolization of DTA.

Ascending Palatine Artery Embolization for the Treatment of Surgically Refractory Post-tonsillectomy Hemorrhage

Severe uncontrollable surgically refractory postoperative bleeding after tonsillectomy is a rare but potentially life-threatening event. The efficacy of surgical interventions tends to decline with repetition, which leads to higher morbidity and mortality. Endovascular embolization of the external carotid artery branches as an effective treatment in surgically refractory post-tonsillectomy hemorrhage has been described previously. We describe the case of a 27-year-old man who presented with surgically refractory post-tonsillectomy hemorrhage and underwent successful endovascular embolization of the ascending palatine artery with immediate hemostasis.

Internal Carotid Artery Agenesis: A Rare Entity

Congenital absence of the internal carotid artery (ICA) is an extremely rare entity that occurs due to insult during the embryonic development of the ICA. Various intracranial collateral pathways develop to compensate for the ICA agenesis. Patients can present with aneurysmal subarachnoid hemorrhage, stroke-like symptoms, or other neurological symptoms due to compression of brain structures from enlarged collateral pathways/aneurysms. We present two cases of ICA agenesis along with an extensive review of the literature. A 67-year-old man presented with fluctuating right-sided hemiparesis and aphasia, found to have left ICA agenesis. The left middle cerebral artery (MCA) is supplied by the basilar artery through the well-developed posterior communicating artery (PCOM). Left ophthalmic artery coming from the proximal left MCA. A 44-year-old woman presented with severe headaches, found to have right ICA agenesis with bilateral MCAs and anterior cerebral arteries (ACA) supplied by left ICA. A 17-mm anterior communicating artery (ACOM) aneurysm was discovered.

Abstract WP129: The Heat Grading Scale as a Neurovascular Remodeling Based Score in Aneurysms Treated With Flow Diversion

Objective: To apply principles of neurovascular remodeling in the classification of flow diverted aneurysms to predict outcomes using the HEAT (Hemodynamics, Endothelialization and Aneurysmal Thrombosis) grading scale.

Introduction: The goal of flow diversion is to exclude an aneurysm from circulation through endothelialization of the aneurysmal neck and hemodynamic induction of aneurysmal thrombosis. Current grading scales do not include the above parameters to evaluate aneurysms after flow diversion.

Methods: Reconstructions using 360° virtual reality (VR) models based on volumetric digital subtraction angiography (DSA) scans of unruptured, wide-neck intracranial aneurysms treated with Pipeline™ from March 2010 to May 2018 at our comprehensive stroke center were built using Surgical Theatre ® . The HEAT grading scale was used to generate a 0 to 15-point score that evaluated residual filling (none 0%, entry remnant <5%, subtotal 5-95%, total >95%), stasis phase (persistent contrast at venous phase, clearance before venous phase, arterial clearance before capillary phase), endoleak (absence, presence), free-hanging edge (absent, present without thrombus, present with thrombus), in-stent stenosis (0-29% minimal, 30-49% mild, 50-69% moderate, 70-94% severe, 95-99% critical), and branch filling (complete, partial TICI 2b >50%, partial TICI 2a <50%, insufficient). Each case was assigned a HEAT score by four neurointerventionalists using DSA, CT angiography (CTA), and the VR model.

Results: Fifty out of 86 Pipeline™ cases had 3D rotational DSA and met technical standards required to build the VR model. Clinical adverse events including central retinal artery occlusion, middle cerebral artery syndrome, and amaurosis fugax were positively associated with HEAT score (n=3, p=<0.001) as were subclinical adverse events including endoleak (n=2) and free-hanging edge with thrombus (n=2) (p=<0.001). Interrater variability was high (k=0.8).

Conclusion: The HEAT grading scale is sensitive, reproducible, and associated with clinical outcome. Larger prospective studies are warranted to validate our results.

Abstract TP38: Efficacy of Middle Meningeal Artery Embolization for Chronic Subdural Hematoma

Background: Symptomatic chronic subdural hematoma (SDH) is treated with surgical evacuation. SDH has a high incidence of recurrence despite evacuation, reported between 2% and 37%. Multiple case reports and case series demonstrate embolization of the Middle Meningeal artery (MMA) for the treatment of chronic SDH to be an adjunct treatment and a possible alternative to surgical evacuation.

Method: Retrospective analysis of patients with chronic SDH who underwent MMA embolization at our community based, Comprehensive Stroke Center between April and August 2019 was done. MMA embolization was performed using 100-300 or 300-500 μm Embospheres.

Results: 18 patients presented with chronic SDH, 55% female. Mean age and modified Rankin score was 70 (range: 48-95 years) and 1 (range: 0-3), respectively. 17 patients (94%) required a total of 20 MMA embolizations. 83% had unilateral MMA embolization and 17% had bilateral MMA embolizations. 100-300 μm Embospheres were used for the MMA embolization in 82% of the patients and 300-500 μm Embospheres in 18% of the patients. 33% had Burr hole prior to the procedure. 5% ( n= 1) patient had Burr hole evacuation after embolization due to Neurosurgeon preference, not neurological deterioration. 56 % patient received treatment to resume anticoagulation/antiplatelet and 44% received prophylactic embolization to prevent reaccumulation after Burr hole evacuation. Mean size of maximum diameter of SDH was 16.9 mm and 4.6 mm of midline shift on admission CT. Mean SDH size and midline shift at discharge was 13 mm and 2.27 respectively. 50% patients had 1 month follow up CT with mean SDH size was 8.2 mm (in comparison to 19.7 in these patients). 17 % (n=3) patients had complete resolution on 3 month follow up. The one patient treated with 300-500 μm Embospheres had an acute on chronic asymptomatic SDH on 1 month follow up CT, requiring accessory meningeal artery embolization with 100-300 μm Embospheres ultimately resulting complete resolution of the SDH at 1 month post embolization.

Conclusion: Despite limited data available, Middle Meningeal artery embolization using 100-300 μm Embospheres leads to reproducible results to prevent recurrence of chronic subdural hematoma. A large randomized controlled study is needed to verify our results.

Abstract WP23: Is There Increased Incidence of Subarachnoid Hemorrhage With Use of Stentrievers in Distal Circulation?

Background: Multiple recent positive endovascular trials have proven mechanical thrombectomy as standard of care for large vessel occlusion (LVO) of the Anterior Circulation (AC). Post-thrombectomy subarachnoid hemorrhage (PT-SAH) is a known complication of this procedure. The aim of this study was to compare the incidence of SAH in proximal (ICA terminus and MCA M1) versus distal (MCA M2 and beyond) LVOs with use of stentrievers.

Methods: Retrospective analysis of patients who underwent anterior circulation acute ischemic stroke interventions (AISI) at a community based, university affiliated comprehensive stroke center during a 5 year period (2014-2019) was done. AISI using stentrievers were separated in 2 groups based on location of LVO (Proximal and Distal). Post procedure CT heads were reviewed for SAH in location of stent deployment.

Results: 2980 patients presented with acute ischemic stroke during the pre-specified time period. Of those, 2,682 were anterior circulation strokes. Of those, 373 received AISI. Stentrievers were used in 193 patients. Proximal occlusions (ICA terminus and MCA M1) were placed into Group A (n=150). Distal occlusions (MCA M2 and beyond) were placed into Group B (n=43). Group A had 6% SAH (n=9); Group B had 16% SAH (n=7) (p value <0.05).

Conclusion: This study reveals an increased incidence of PT-SAH for distal LVOs. Main limitation of the study is the small sample size. Next generation stentrievers with smaller stent size and different design may decrease incidence of PT-SAH. Larger prospective RCTs are warranted to validate these results.

Institution of Code Neurointervention and Its Impact on Reaction and Treatment Times

BACKGROUND/OBJECTIVE

Various strategies have been implemented to reduce acute stroke treatment times. Recent studies have shown a significant benefit of acute endovascular therapy. The JFK Comprehensive Stroke Center instituted Code Neurointervention (NI) on May 1, 2014 for the purpose of rapidly assembling the NI team and rapidly providing acute endovascular therapy.

DESIGN/METHODS

We performed a retrospective analysis of all patients who had Code NI (Code NI group) called from May 1, 2014 to July 30, 2018 and compared them to patients who underwent acute endovascular treatment prior to initiation of the code (pre-Code NI group) between January 2012 and April 30, 2014. The following parameters were compared: door to puncture (DTP) and door to recanalization (DTR) times, as well as preprocedure NIHSS, 24-hour postprocedure NIHSS, and 90-day modified Rankin scores.

RESULTS

There were 67 pre-Code NI patients compared to 193 Code NI patients. Mean and median DTP times for pre-code NI vs Code NI patients were 161 minutes(mins) vs 115mins (p<0.0001, 31.76-58.86) and 153mins vs 112mins (p <0.0001), respectively. Mean and median DTR times were 220 mins vs 167mins (p <0.0001, 37.76-69.97) and 225mins vs 171mins (p <0.0001). Mean pre-procedure NIHSS was 16 for both groups while 24 hours post procedure NIHSS was 10.6 vs 10.8 (p =.078, 1.8-2.38). Mean 90 day mRS was 2.15 vs 1.65 (p=0.036, 0.32-0.96).

CONCLUSION

Institution of Code NI significantly improved DTP and DTR times as well as mRS at 3-months postprocedure. Rapid assembly of the NI team, rapid availability of imaging and angiography suite, and streamlining of processes, likely contribute to these differences. These lessons and more widespread institution of such codes will further aid in improving acute stroke care for patients.

Safety and Clinical Outcomes after Transverse Venous Sinus Stenting for Treatment of Refractory Idiopathic Intracranial Hypertension: Single Center Experience

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a syndrome of elevated intracranial pressure of unknown etiology. Unilateral or bilateral transverse sinus (TS) or transverse-sigmoid junction stenosis is present in about 30%-93% of these patients. There is an ongoing debate on whether venous sinus stenosis is the cause of IIH or a result of it. The subset of IIH patients who continue to have clinical deterioration despite maximum medical therapy is termed as "refractory IIH." Traditionally, cerebrospinal fluid diversion surgeries (ventriculoperitoneal shunt and lumboperitoneal shunt) and optic nerve sheath fenestration (ONSF) were the mainstays of treatment for refractory IIH. In the last decade, venous sinus stenting (VSS) has emerged as a safe and effective option for treating refractory IIH patients with venous sinus stenosis. Through this study, we want to share our experience with venous stenting in refractory IIH patients with venous sinus stenosis associated with a significant pressure gradient (≥10 mm Hg).

METHODS

Retrospective chart review of all the patients diagnosed with refractory IIH who underwent VSS or angioplasty at our comprehensive stroke center from November 2016 to March 2019.

RESULTS

A total of seven refractory IIH patients underwent VSS or angioplasty within the specified period. The mean age was 39 years. Eighty-five percent of the patients were women (n = 6). The mean body mass index (BMI) was 37 kg/m². Headache was the most common symptom (85%, n = 6) followed by transient visual obscurations (71%, n = 5) and pulsatile tinnitus (57%; n = 4). All patients had papilledema. Fifty-seven percent of patients (n = 4) had impaired visual field. Mean lumbar opening pressure was 40.6 cm H₂O (SD = 9.66; 95% CI = 33.5-47.7). All patients were on maximum doses of acetazolamide ± furosemide. Six patients (85%) had dominant right transverse-sigmoid sinus. Fifty-seven percent of the patients had severe right transverse ± sigmoid sinus stenosis (n = 4) and the rest (43%) had bilateral TS stenosis (n = 3). Prestenting mean trans-stenosis pressure gradient was 18 mm Hg (SD = 6.16; 95% CI = 13.43-22.57). Six patients (85%) were treated with TS stenting and one (15%) with only angioplasty. Poststenting mean trans-stenosis pressure gradient was 4.8 mm Hg (SD = 6.6; 95% CI = -0.1-9.7). All patients were able to come off their medications with significant improvement in neurological and ophthalmological signs and symptoms. No procedure-related complications occurred.

CONCLUSION

TS stenting ± angioplasty is a safe and effective means of treating refractory IIH with venous sinus stenosis associated with a significant pressure gradient (≥10 mm Hg).

Abstract TP21: Did evolution of Evidence Based Stroke Thrombectomy treatment change Efficiency across Stroke Systems of Care?

Background: Negative thrombectomy trials (IMSIII, MRRESCUE, Synsthesis expansion) resulted in very cautious selection of patients who underwent thrombectomy which probably caused delay in deciding neurointervention. With the positive results of the Big Five trials, mechanical thrombectomy within 6 hours became standard of care. DAWN broadened the horizon of mechanical thrombectomy to 24 hours of last known normal. To expedite mechanical thrombectomy at our community hospital we have implemented Code Neurointervention in addition to Code Stroke. Our purpose in this study is to analyse the effect of positive trials on code neurointervention time.

Methods: All patients who received mechanical thrombectomy at our university affiliated community comprehensive stroke center from January 2014 till July 2018 were analyzed. Patients were divided in three groups: A)Pre Big Five Trials era (Jan 2014 -Dec 2014), B) Post Big five trials to pre DAWN trial (Jan 2015 - May 2017) and C) Post DAWN trial era (Jun 2017 - July 2018). We compared the time interval between Code stroke and Code Neurointervention (in minutes) among these three groups. Code stroke: time when any patient with acute neurological change within last 24 hours is encountered. Code Neurointervention: time when Vascular Neurologist and Neurointerventionalist decide to pursue endovascular therapy.

Results: Out of 2423 ischemic stroke patients, 262 received endovascular therapy. Group A (n=38, males =18 (47%), mean age=72 years); group B (n=137, males=67 (77%), mean age=68 years); group C (n=87, males= 47 (54%), mean age=71 years). It took about about 110 minutes to decide neurointervention in group A (SD=70; 95 CI= 88 -133), 72 minutes in group B (SD= 50; 95 CI= 67-81) and 64 minutes in group C (SD=40; 95 CI =54 -73). All intergroup differences were statistically significant (p value < 0.05).

Conclusion: Accumulation of recent evidence based data has progressively and significantly reduced the time to decision for neurointervention. Improvement in time efficiency is probably multifactorial. Larger trials are required to corroborate our findings.

Abstract WP476: Transfer to Nearest Primary Stroke Center Portends Significant Delays and Poorer Outcomes in Stroke Patients With Large Vessel Occlusions

Background: Comprehensive stroke centers (CSC) provide around the clock complex services when compared primary stroke centers (PSC) for acute ischemic stroke patients. As most stroke treatments are time-sensitive, a delay in admitting these patients due to transfer from PSC can cause an increased degree of dependence and disability and poorer outcomes. This is due to CSC’s having more robust availability of intravenous, intra-arterial, and endovascular revascularization therapies. We propose that patients that are transferred to a CSC from PSC have increased onset to puncture times and are more likely to have a larger degree of disability compared to those who are directly admitted to comprehensive stroke centers.

Methods: Patients were evaluated over a 30-month period from January 2016- July 2018 using retrospective data from a university affiliated community based comprehensive stroke center. The time of onset of symptoms were recorded as well as the puncture times for stroke thrombectomy patients. Patients were separated by arrival mode and times were analyzed using average calculations. Modified Rankin Scores for all of the patients were collected using existing registry data and follow up visits. GraphPad Quick Calcs Web site was used to obtain descriptive statistics and intergroup differences.

Results: A total of 1,412 ischemic stroke patients from January 2016 to July 2018 were studied. The patients that were transferred from other facilities (n=70) took longer to initiate acute interventional treatment than those that arrived via EMS from the field (n=156); 474 minutes vs 389 minutes respectively; from the onset of symptoms to recanalization (a delay of more than an hour). The patients that were transferred from other facilities had a median mRS score of 3, while the patients that arrived by EMS from the field had a median MRS score of 1 at 90 days. The multivariate analysis performed took into account the risk factors and initial clinical severity. The 90 days’ outcome were statistically significantly different (p<0.01).

Conclusion: Patients that arrive to the CSC via EMS are promptly triaged and treated sooner than those that arrive to PSC’s prior to being transferred to CSC’s. This loss of time results in a statistically significant poorer outcome.

Acute Ischemic Pediatric Stroke Management: An Extended Window for Mechanical Thrombectomy?

Ischemic stroke is a rare condition to afflict the pediatric population. Congenital cardiomyopathy represents one of several possible etiologies in children. We report a 9-year-old boy who developed right middle cerebral artery stroke secondary to primary restrictive cardiomyopathy. In the absence of pediatric guidelines, the child met adult criteria for mechanical thrombectomy given the small core infarct and large penumbra. The literature suggests children may benefit from mechanical thrombectomy in carefully selected cases. Our patient exemplifies specific circumstances in which acute stroke therapy with thrombolysis and thrombectomy may be safe.

Neuroscience step-down unit admission criteria for patients with intracerebral hemorrhage

OBJECTIVES

The goal of our study is to determine optimal criteria which can be used to avoid admission to neuroscience intensive care units for patients with intracerebral hemorrhage (ICH).

PATIENTS AND METHODS

This is a retrospective cohort study of 431 patients with primary ICH from January 2013 to the end of December 2015 and reviewed multiple admitting characteristics. Based on these needs, we tested the following step-down unit admission criteria: Supratentorial ICH, ICH volume <20 cc, no Intraventricular hemorrhage (IVH), systolic BP <200mmHg, no respiratory failure, GCS≥12. We classified 431 patients into two groups; 1-Patients who met step-down unit admission Criteria (71 patients). 2-Patients who didn't meet the criteria (360 patients).

RESULTS

In our patients, 16.5% fulfilled the criteria. Length of stay in the ICU was 1.43days in step-down unit admission criteria patients. None of the patients who fulfilled the criteria were readmitted to the ICU, compared to 3 readmissions among the group of patients who did not fulfill the criteria (P=0.82). None of these patients required a neurosurgical procedure vs 47 patients (10.9%) in the other group (P=0.04). Among patients who met the criteria, 83.1% were discharged home or rehab RR 0.33 CI (0.19-0.55), (P<0.0001).

CONCLUSION

We propose that patients who fulfill step-down unit admission criteria can be safely monitored in stroke unit and they have no need for ICU admission. Further studies are needed to validate these criteria in a prospective manner.

Abstract TP289: Code Neuro-Intervention a New Necessity: Reality of Shifting Stroke Care Paradigm

Background: Various strategies have been implemented to reduce acute stroke treatment times. A unique code process pathway was designed at our hospital specifically to be activated by the stroke team for the purpose of rapidly assembling the Neurointerventional team.

Methods: Code Neurointervention (NI), was designed and tested from January 2014 to April 2014 for all the patients who presented with ischemic strokes to our community based, university affiliated comprehensive stroke center. We retrospectively analyzed all patients who had Code NI called from May 1, 2014 to April 30, 2015 and compared them to patients who underwent acute endovascular treatment the prior year (Non Code NI). The following parameters were compared: decision to recanalization and door to recanalization times. Further analysis was done to compare patients presenting during business hours (Monday-Friday 8am-5pm) and off hours using GraphPad QuickCalcs Web site.

Results: There were 28 Code NI; 14 were called during work hours and 14 during off hours. The previous year 25 patients underwent acute endovascular intervention; 12 during work hours and 13 during off hours. Mean decision to recanalization time was 106 (Code NI) vs 115 minutes (Non Code NI) (p<0.0.6) during work hours and 154 (Code NI) vs 139 minutes (Non Code NI) (p<0.37) during off hours. Mean door to recanalization time was 169 (Code NI) vs 173 minutes (Non Code NI) (p<0.85) during work hours and 252 (Code NI) vs 243minutes (Non Code NI) (p< 0.75) during off hours. Subset analysis of time parameters for patients in Code NI group showed mean decision to recanalization times of 106 minutes during work hours vs 154 minutes off work hours (p<0.004). Mean door to recanalization times were 169 minutes vs 251 minutes (p<0.0003), respectively.

Conclusion: Institution of Code NI significantly improved intervention time parameters during work hours as compared to off hours. Rapid assembly of the neurointervention team, rapid availability of imaging and angiography suite likely contribute to these differences. Further initiatives, such as improving neurointervention staff availability during off hours or cross training other staff can further improve acute intervention time parameters.

Abstract WMP8: Thin-sliced Reformatted CT Imaging: Validation of a Safer and Faster Technique to Assess Clot Size and Vessel Diameter in Large Vessel Occlusions

Background: Thin-sliced reformatted non-contrast CT head are not widely used to detect the thrombus. The purpose of this study was to investigate whether thin-sliced reformatted non-contrast CT scans could be reliably used to detect and measure size of the thrombus size in patients with acute ischemic stroke due to LVO and therefore serve as a potential substitute of CT Angiogram (CTA). Success of this paradigm could reduce stroke decision algorithm to nonenhanced CT scan before a code neurointervention is activated; hence saving time and contrast.

Methods: Comprehensive prospective analysis of patients who underwent acute endovascular intervention for LVOs at a community based, university affiliated comprehensive stroke center during one year period (Jan 2015-Dec 2015) was done. The raw data of non-enhanced CT scans and CTAs were collected. All raw data were reconstructed with thin slices of 0.625 mm using standard GE software. Two observers independently evaluated the 5-mm maximum intensity projections of the thin slices and CTA in coronal and axial projections for best assessment of vessel diameter and thrombus length. Inter-observer agreement was measured using Cohen κ.

Results: There were 749 patients who presented with acute ischemic stroke during the specified time period. Of those 67 were large vessel circulation strokes; of which, 22 had both CT and CTA done. Mean clot length measured was 14.75 (SD +/-4.95) on thin slices CT and 15.02 (SD +/-5.47) on CTA. Vessel diameter measured was 2.77 (SD +/-0.47) on thin sliced reformatted CT and 2.41 (SD +/-0.49) on CTA. There were no instances where clot size or vessel diameter could not be measured on thin slice reformatted CT. Inter-observer agreement was higher for both CTA (κ, 0.83) versus thin-slice nonenhanced CT reconstructions (κ, 0.80).

Conclusions: Thin-sliced reconstructions of standard cranial nonenhanced CT raw data can be reliably used to detect and measure the thrombus size in LVOs. It also reliably measures the vessel diameter, making intervention planning possible. Larger multicenter trials are needed to validate our data.

Abstract WP129: MRI and Non Contrast CT Clot Imaging for Successful Large Vessel Clot Resolution of Posterior Circulation Ischemic Strokes

Background: Thrombi retrieved from patients with an acute ischemic stroke with Large Vessel Occlusion (LVO) and correlation with hyperdense vessel sign seen on non contrast CT and blooming artifact seen on gradient-echo(GRE) MRI have given relevant insights into the pathophysiology of thrombotic lesions (RBC-dominant vs Fibrin-dominant). This may facilitate the development of safer noninvasive reperfusion treatment approaches. Our goal was to evaluate the benefit of anticoagulation for posterior circulation strokes based on imaging characteristics in patients where endovascular therapy was not justified.

Method: Comprehensive prospective evaluation of patients who presented with posterior circulation LVOs at a community based, university affiliated comprehensive stroke center during one year period (January 2015-December 2015) was done. The clot characteristics on thin-sliced reformatted CT, CT Angiogram and GRE MRI were noted. The clot size and characteristics were followed by sequential imaging while the patients were on anticoagulation for presumed embolic thrombus.

Results: Total 749 patients presented with acute ischemic stroke during the pre-specified time period. Of those 78 were posterior circulation strokes; of which, 7 had LVO and 4 underwent endovascular treatment. Endovascular therapy was not justified in 3 patients due to clinically stable exam. These patients were thought to have embolic etiology of stroke and therefore were started on anticoagulation. Group A (RBC-dominant thrombus; n=2) mean clot length was 15.5mm, measured on CT, CTA, MRI. GRE MRI showed blooming artifact around the area of thrombus. Thrombus resolved on repeat CTA at 48-72hours. Group B (Fibrin-dominant; n=1) 5.5mm clot was visualized only on CTA (nothing on CT head and MRI) and it persisted on repeat CTA at 48-72hours. Mean initial NIHSS was 2 (SD +/- 1 ). Mean discharge NIHSS was 0.33 (SD +/- 0.577). Mean discharge mRS was 0.67 (SD +/- 0.57).

Conclusion: Hyperdense sign on reformatted thin-sliced CT head and blooming artifact on GRE MRI brain in patients with LVO can be used to characterize the composition of thrombus, which could be helpful in deciding medical therapy. A larger prospective randomized trial is needed to corroborate our findings.

Ischemic Stroke After Wasp Sting

BACKGROUND

Despite the common occurrence of hymenopteran stings worldwide, primary neurologic manifestations including stroke are rare. We report a case of a healthy male who developed a right middle cerebral artery (MCA) territory ischemic stroke after getting stung by a wasp.

CASE REPORT

A 44-year-old man with hypertension presented to the hospital with sudden-onset left hemiparesis, left facial weakness, and dysarthria after being stung by a wasp. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) scans of the brain revealed a right MCA territory infarct and a lack of flow in the distal right internal carotid artery and MCA. He was treated with intravenous tissue plasminogen activator. A computed tomography angiography scan of the brain performed 24 hours later revealed multiple regions of vasoconstriction in the territory of the bilateral MCA. Evaluations for causes of stroke, including echocardiography and telemetry, were not revealing. Immunologic testing showed significantly elevated levels of serum wasp immunoglobulin E. Therapy with aspirin and atorvastatin was started. At discharge, the patient had a mild left facial droop but normal strength in his left arm and leg. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians encounter large numbers of hymenopteran sting cases each year. These patients typically present with local reactions, such as itching, pain, and erythema. Systemic manifestations, such as anaphylaxis causing severe hypotension and bronchospasm, are less common but deadly. Neurologic complications, such as ischemic stroke, are extremely rare. This manuscript highlights the pathophysiology and management of stroke after a hymenopteran sting. There are no guidelines for the management of stroke after a hymenopteran sting, and therefore we intend to provide some guidance to physicians for treating stroke after a hymenopteran sting.

Auditory Hallucinosis as a Presenting Feature of Interpeduncular Lipoma with Proximal P1 Segment Fenestration: Report of a Rare Case and Review of Literature on Peduncular Hallucinosis

The authors present a unique case of intracranial lipoma in the interpeduncular cistern associated with proximal P1 segment fenestration. This patient is a 20-year-old male with extensive psychiatric history and complaints of recent auditory hallucinations. Cranial magnetic resonance imaging (MRI) (T1, T2, and FLAIR) showed a hyperintense lesion in the left aspect of interpeduncular cistern with a prominent flow void within the hyperintense lesion suggestive of a combined vascular-lipomatous lesion. Computed tomography (CT) angiography showed a high-riding large tortuous P1 segment on the left side with proximal fenestration, the ectatic posteromedial limb harboring a fusiform dilated segment. Since there are anecdotal cases of cerebral aneurysms associated with intracranial lipomas, a conventional angiography was done, which confirmed a proximal left P1 fenestration and a fusiform-dilated segment, and no aneurysm. There are few cases of hallucinations associated with a vascular midbrain pathology reported in literature, but hallucinations associated with a combination of lipoma and arterial ectasia have never been reported. This article not only demonstrates the MRI and angiographic appearance of this rare lipomatous lesion but also highlights this unique association and significance of auditory hallucinations as a clinical presentation, akin to peduncular hallucinosis.

Lingual Artery-Retromandibular Vein Fistula Four Years after an Uncomplicated Carotid Endarterectomy: Case Report and Review of Possible Etiologies and Treatment Options

The external carotid artery's lingual branch to retromandibular venous fistula following a carotid endarterectomy has not been reported earlier in literature. We report a unique case of an 87-year-old man who had a right-sided carotid endarterectomy in 2009 and presented four years later with complaints of fullness and discomfort in the area of right parotid gland with associated pulsatile tinnitus. A computed tomography (CT) scan of the neck revealed a deep portion of the right parotid gland having abnormal aneurysmal dilatation of a vascular structure, which appeared to be an arteriovenous fistula between branches of right external carotid artery and the retromandibular vein. Conventional catheter angiogram showed a complex arteriovenous fistula seen with the right retromandibular vein receiving multiple small arterial feeders from the right external carotid artery via its lingual artery branch. Slight reflux was noted into the right pterygoid plexus, right maxillary, and right submental veins as well. Surgical treatment was deferred due to high risk of inadvertent facial nerve injury from extensive parotid dissection involved in the procedure. Transarterial embolization of five discrete arterial branches from the right external carotid artery supplying the fistula was performed using particles with resultant remarkable slowing of the venous drainage into the retromandibular vein. After the procedure, his tinnitus and ear fullness resolved completely. The presence of arteriovenous fistula after carotid endarterectomy is a rare yet serious complication and therefore should be diagnosed early and treated promptly. The article highlights the relevant literature on arteriovenous fistula formation in the setting of arterial patch, intraoperative shunting, and surgical-site infections.

Abstract 3708: Safety and Efficacy of Antiplatelet Monotherapy (clopidogrel) in Stent Assisted Elective Coil Embolization of Cerebral Aneurysms

BACKGROUND AND PURPOSE: Thromboembolic events are the most common complication seen in elective coil embolization of cerebral aneurysms. Previous studies have shown that administration of oral clopidogrel and/or aspirin may lower the thromboembolic complication rate but little data exists regarding clinical outcome with the use of antiplatelet monotherapy in stent assisted elective aneurysm coil embolization.

Objectives: To assess the safety and efficacy of antiplatelet monotherapy (clopidogrel) in elective stent assisted coil embolization of cerebral aneurysms

MATERIALS AND METHODS: Retrospective chart review was performed in 94 consecutive patients who underwent endovascular treatments for elective coil embolization of cerebral aneurysms between 2008-2010. Thirty patients were included in this study who met the inclusion criteria of stent assisted coil embolization. All these patients received 75mg clopidogrel for one week prior to the procedure. Clopidogrel was continued post procedure for six to eight weeks. Primary outcome measure was peri-procedure and post-procedure symptomatic thromboembolic complications.

RESULTS The study included 23 females and 7 males with mean age 52.6 years.Twenty (66.7%) patients had anterior circulation aneurysms and 10 (33.3%) patients had posterior circulation aneurysms. Twenty (66.7%) patients were treated with Neuroform, 9 (30%) patients with Enterprise stent and 1 (3.3%) patient was treated with both Neuroform and Enterprise stent assisted coil embolization. One (3.3%) patient had an iatrogenic flow limiting vertebral artery dissection during embolization of vertebrobasilar artery aneurysm with no clinical deficit. The patient’s vertebral artery dissection was treated with 2 Wingspan stents and 1 Medtronic driver stents. Symptomatic thromboembolic complication was seen in 1 patient (3.3%) at discharge. The patient had a giant basilar tip aneurysm which was treated with stent assisted coil embolization. Postprocedure the patient had a right facial palsy with gaze deviation. The MRI was consistent with acute posterior circulation stroke. The patient was discharged home with a modified Rankin Scale <2. Follow up at six to eight weeks post procedure clinical data was available for 21 patients (73.3%). No delayed thromboembolic complication was observed in these patients at follow up visit.

CONCLUSION: Oral clopidogrel is safe and efficacious as an antiplatelet monotherapy during elective stent assisted coil embolization. Further multicenter prospective trials are warranted to evaluate safety and efficacy of clopidogrel as a monotherapy for elective stent assisted coil embolization.