Candidates For Endovascular Therapy Research Articles

Abstract 90: Optimizing Triage Assessments for Large and Medium Vessel Occlusions

Introduction: Stroke symptom assessment tools are used in various settings, including telestroke triage, to identify patients who may be candidates for endovascular therapy (EVT). EVT is now being offered to more patients including those with medium vessel occlusions (MeVOs). We hypothesize that triage screening tools have differing rates of detection for large vessel occlusions (LVOs) versus medium vessel occlusions (MeVOs). Methods: Using our 2021 stroke registry, we created a retrospective cohort of ischemic stroke patients with LVO, MeVO or no occlusion. Patients were treated with the standard of care (e.g., thrombolytics, EVT). Clinical and radiographic data were abstracted for each case. Patients were evaluated for hemiparesis (HP) and vision, aphasia, or neglect (VAN) using the documented presenting exam. ROC analysis was conducted to evaluate the ability of the HP + VAN screening tool to detect LVOs and MeVOs. Results: The cohort consisted of 299 patients (median age 66 years, 48% female, 36% Black, median NIHSS score 9). Among the 175 patients with recorded HP + one of the VAN signs, 81% (n=141) had an occlusion (LVO or MeVO). HP+VAN criteria was not met by 11% of LVOs and 33% of MeVOs. HP + VAN tool performed best for the combined endpoint of LVO or MeVO (sensitivity 0.83, specificity 0.74, AUC 0.786, Figure). Variations of this tool did not significantly improve performance (additional models with AUCs will be presented) with the exception of changing the score to from HP+VAN to “HP or VAN” (sensitivity 1.00, specificity 0.25). Conclusions: In our sample from a tertiary care center, HP+VAN is a reasonable tool for the detection of LVOs or MeVOs. The only variation that improved sensitivity was screening for hemiparesis or VAN. While this prevented us from missing any LVOs or MeVOs, this approach comes at a heavy cost of reduced specificity.

An Endovascular- Versus a Surgery-First Revascularization Strategy for Chronic Limb-Threatening Ischemia: A Meta-Analysis of Randomized Controlled Trials

Timely revascularization is essential for limb salvage and to reduce mortality in patients with chronic limb-threatening ischemia (CLTI). In patients who are candidates for endovascular therapy and surgical bypass, the optimal revascularization strategy remains uncertain. Recently published randomized controlled trials (RCTs) have presented conflicting results. We conducted a trial-level meta-analysis to compare the outcomes between endovascular-first and surgery-first strategies for revascularization. PubMed, Web of Science, and the Cochrane Library were searched to identify RCTs comparing the outcomes of endovascular-first versus surgery-first strategies for revascularization in patients with CLTI. Data were pooled for major outcomes and their aggregate risk ratios (RRs) with 95% confidence intervals were calculated using a random-effects model. Kaplan-Meier curves for amputation-free survival and overall survival time were plotted using the pooled aggregated data from published curves, with their corresponding hazard ratios (HRs) and 95% confidence intervals reported for up to 5 years of follow-up. A total of 3 RCTs with 2,627 patients (1,312 endovascular-first and 1,315 surgery-first) were included in the meta-analysis. Of these, 1,864 patients (70.9%) were men and 347 (13.2%) were older than 80 years. Comparing the endovascular-first and surgery-first approaches, there was no significant difference in the overall (HR 0.92 [0.83 to 1.01], p = 0.09) or amputation-free survival (HR 0.98 [0.92 to 1.03], p = 0.42), reintervention (RR 1.24 [0.74 to 2.07], p = 0.41), major amputation, (RR 1.16 [0.87 to 1.54], p = 0.31), or therapeutic crossover (RR 0.92 [0.37 to 2.26], p = 0.85). In conclusion, data from available RCTs suggest that there is no difference in clinical outcomes between endovascular-first and surgery-first revascularization strategies for CLTI. A planned patient-level meta-analysis may provide further insight.

Abstract 107: Endovascular Therapy for Tandem Vertebral and Basilar Artery Occlusion in a Patient with Low NIHSS

Introduction Basilar artery occlusion (BAO) is a devastating minority stroke subtype with variable clinical presentations and high mortality.1,2 The National Institute of Health Stroke Scale (NIHSS) cutoff for poor outcomes is lower in BAO compared to anterior circulation large vessel occlusions (LVO) due to the scale’s weighted scoring towards cortical signs.3,4 To bridge this gap, Alemseged et.al created the underutilized posterior circulation (PC) NIHSS as an improved stroke assessment tool in PC LVO to better identify endovascular therapy (EVT) candidates. 5 Current randomized trials point to mixed evidence regarding EVT for BAO; although recent studies such as Endovascular Treatment for Acute Basilar Artery Occlusion (ATTENTION)6 and Basilar Artery Occlusion Chinese Endovascular Trial (BAOCHE)7 suggest positive results of EVT within 24hrs. Smaller retrospective subgroup analyses demonstrated EVT for BAO with low NIHSS has good clinical outcome of modified Rankin Scale (mRS) 0‐2 at 3 months in 60‐70% of patients4,8. We present a case of tandem vertebrobasilar artery occlusion in a patient with subacute symptoms and low NIHSS treated with mechanical thrombectomy. Methods '‐ Results 41‐year‐old male with past medical history of hypertension, insulin dependent diabetes and active smoking presented with worsening vertigo, nausea and vomiting for 3 weeks with progression to right sided headache and syncope. EMS noted right facial weakness prompting transport to nearest primary stroke center where CT head non‐contrast showed right cerebellar infarct and CT angiogram (CTA) head and neck showed right vertebral artery occlusion with basilar extension. Intravenous thrombolytic (IVT) was deferred due to unclear last known well. He was treated with aspirin 324mg and transferred to our tertiary stroke center. Arrival NIHSS was 1 for right upper extremity ataxia. Premorbid mRS was 0. Repeat CTA redemonstrated right vertebrobasilar artery tandem occlusion. CT perfusion was without mismatch. Patient underwent emergent mechanical thrombectomy with ADAPT to TICI3 revascularization with future plan for possible angioplasty and stenting of R vertebral stenosis. Subsequently admitted to neurocritical care unit and treated with dual antiplatelet therapy. Initially maintained on aspirin and Cangrelor infusion, then transitioned to aspirin and Plavix without hemorrhagic conversion. Diffusion weighted MRI brain showed right cerebellar and right pontine infarcts. Hospital course was complicated by severe intractable hiccups due to area postrema syndrome; ultimately resolved with baclofen and gabapentin after extensive unsuccessful medication trails. NIHSS remained 1 for ataxia throughout admission, although exam also revealed mild unsteady gait requiring home physical therapy and a walker on discharge. Post‐stroke mRS was 1 on discharge; 3‐month mRS is pending. Conclusion Evidence regarding EVT for low NIHSS BAO remains varied with some studies showing superior benefit with IVT alone9 while others suggest improved outcomes with EVT in mild to moderate deficits.4,8 One prospective study particularly revealed better outcomes in EVT for BAO due to tandem occlusions similar to this case.10 Given the potential devastating sequalae of BAO and limited overall treatment options, EVT should remain a strong contender for treatment of PC LVO, especially in patients with milder neurologic deficits or tandem occlusions. Additionally, heightened use of PC‐NIHSS may better prognosticate candidates for EVT.

Nomogram-Based Prediction of the Futile Recanalization Risk Among Acute Ischemic Stroke Patients Before and After Endovascular Therapy: A Retrospective Study.

Futile recanalization (FRC) is common among large artery occlusion (LAO) patients after endovascular therapy (EVT). We developed nomogram models to identify LAO patients at a high risk of FRC pre- and post-EVT to help neurologists select the optimal candidates for EVT. From April 2020 to July 2022, EVT and mTICI score ≥2b LAO patients were recruited. Nomogram models was developed by two-step approach for predicting the outcomes of LAO patients. First, the least absolute shrinkage and selection operator (LASSO) regression analysis was to optimize variable selection. Then, a multivariable analysis was to construct an estimation model with significant indicators from the LASSO. The accuracy of the model was verified using receiver operating characteristic (ROC), calibration curve, and decision curve analyses (DCA), along with validation cohort (VC). Using LASSO, age, sex, hypertension history, baseline NIHSS, ASPECTS and baseline SBP upon admission were identified from the pre-EVT variables. Model 1 (pre-EVT) showed good predictive performance, with an area under the ROC curve (AUC) of 0.815 in the training cohort (TrC) and 0.904 in VC. Under the DCA, the generated nomogram was clinically applicable where risk cut-off was between 15%-85% in the TrC and 5%-100% in the VC. Moreover, age, ASPECTS upon admission, onset duration, puncture-to-recanalization (PTR) duration, and lymphocyte-to-monocyte ratio (LMR) were screened by LASSO. Model 2 (post-EVT) also demonstrated good predictive performance with AUCs of 0.888 and 0.814 for TrC and VC, respectively. Under the DCA, the generated nomogram was clinically applicable if the risk cut-off was between 13-100% in the TrC and 22-85% of VC. In this study, two nomogram models were generated that showed good discriminative performance, improved calibration, and clinical benefits. These nomograms can potentially accurately predict the risk of FRC in LAO patients pre- and post-EVT and help to select appropriate candidates for EVT.

Effectiveness and Safety of Tecneplase vs. Alteplase in the Acute Treatment of Ischemic Stroke

Not all hospitals have interventional radiology services. This fact implies that in centers where this resource is not available, the treatment of stroke in the acute phase must be adapted and individualized. The aim of the study is to determine and compare the combined effect of thrombolysis and thrombectomy effectiveness and safety of tenecteplase versus alteplase in the acute treatment of ischemic stroke in patients who are candidates for endovascular therapy according to clinical practice guidelines. This paper details a retrospective multicenter cohort study of patients with ischemic stroke admitted in three hospitals between 2018 and 2020. The main outcome variables were the degree of recanalization and the functional outcome at 3 months; safety variables were mortality and the occurrence of intracranial hemorrhage (ICH). In total, 100 patients were included, 20 of which were treated with tenecteplase (TNK) and 80 with alteplase (rtPA). Of those treated with TNK, 75% obtained a successful recanalization compared to 83.8% in those treated with rtPA (OR 0.58; 95% CI 0.18–1.88; p = 0.56). No differences were found in obtaining an excellent functional result at 3 months (35% TNK vs. 58.8% rtPA; p = 0.38). Tenecteplase showed worse neurological results after 24 h (unfavorable result of 70% with TNK vs. 45% with rtPA; OR = 5.4; 95% CI 1.57–18.6). No significant differences were identified in mortality; 17.5% with rtPA and 20% with TNK (p = 0.79), nor in the appearance of intracranial hemorrhage ICH (15.2% with rtPA vs. 30% with TNK (p = 0.12). In our series, there were not significant differences shown regarding effectiveness and safety between tenecteplase and alteplase.

Extra- Anatomical Bypass Applications Still as an Alternative in Progressive Aortoiliac Occlusive Disease Manegement

Aims: Extra-anatomical bypass (EAB) is still an important alternative treatment method in patients with aortoiliac occlusive disease (AIOD). Settings and Design: In this study, we assessed the results of EAB procedures, over a 22-year period, based on 30-day morbidity and mortality, 1st month, 1st, 3rd, and 5th year patient survival, primary patency, and limb salvage rates. Subjects and Methods: A retrospective review and analyze was performed on a single-center database of consecutive 46 patients who underwent femorofemoral or axillofemoral bypass grafting procedures from 1998 to 2020. All patients were called to followed up and were performed clinical examination and color duplex ultrasound (CDUS) evaluation for determination of graft patency. The surviving patients were followed-up for 5 years. Statistical Analysis Used: Five-year survival, graft patency, and limb salvage rates were calculated by the Kaplan–Meier method. Results: The 46 subjects included 25 (54.3%) femoral and 21 (45.7%) axillary bypass applications. The mean age was 64.2 ± 12.8 years (28–82) and 36 were male (78.3%). Critical limb ischemia was the most accounted indication for EAB surgery (25/54.4%). The cumulative mortality rate was 34.8% at 5 years' period. The graft patency and limb salvage rates for femoral and axillary applications were 59.2% versus 57.4% and 86.4% versus 80% at 5 years, respectively. Conclusions: Femorofemoral and axillofemoral bypasses are suitable for patients with AIOD requiring revascularization for relief of symptoms or limb salvage, who are not candidates for endovascular therapy or who are at high risk for direct anatomical revascularization.

Abstract TP254: A Comparison of Models for Evaluation and Transfer of Patients With Suspected Large Vessel Occlusions

Introduction: Mechanisms for the hospital identification of patients with suspected large vessel occlusions (LVO) vary widely based on referring and receiving stroke center resources. We compared processes for identifying patients with suspected LVO who may be candidates for endovascular therapy (EVT) at non-EVT hospitals and the criteria for interfacility transport to Comprehensive Stroke Centers (CSC) for potential EVT. Methods: Data were obtained from 4 CSC which serve distinct geographic regions, ranging from rural to urban environments, over a continuous 12 month period of time beginning year 2018. Patients transferred from all referring hospitals to these facilities were considered regardless of hospital affiliations (n=2213). Geographic description, imaging modalities and form of emergent neurologic consultation available and utilized, rates of stroke transfers for EVT, and rates of final EVT were recorded. Results: The process for identifying a patient with a likely LVO appropriate for interfacility transfer varied greatly by referring and receiving hospital (table). The intensity of referring hospital evaluation ranged from complete multimodal CT imaging and either onsite or video telestroke consultation with access to neuroimaging to simple noncontrast CT and telephone consultation. Rates of transfer and eventual EVT varied across the centers. Further details of the form of stroke expertise, penumbral imaging criteria, unique geographic variances, criteria for transfer, and final utilization of EVT will be presented. Conclusions: Optimal interfacility transfer procedures are essential to ensure patients with LVO are considered in a timely fashion, and that over triage does not overwhelm receiving CSC. We found significant process variations in identifying EVT candidates for interfacility transfer. Providing examples of multiple best practices allows for other centers to identify potential solutions for their unique circumstances.

Endovascular Treatment Decisions in Patients with M2 Segment MCA Occlusions.

Endovascular therapy in acute ischemic stroke is rapidly evolving. We explored physicians' treatment attitudes and practice in patients with acute ischemic stroke due to M2 occlusion, given the absence of Level-1 guidelines. We conducted an international multidisciplinary survey among physicians involved in acute stroke care. Respondents were presented with 10 of 22 case scenarios (4 with proximal M2 occlusions and 1 with a small-branch M2 occlusion) and asked about their treatment approach under A) current local resources, and B) assumed ideal conditions (no monetary or infrastructural restraints). Overall treatment decisions were evaluated; subgroup analyses by physician and patient baseline characteristics were performed. A total of 607 physicians participated. Most of the respondents decided in favor of endovascular therapy in M2 occlusions, both under current local resources and assumed ideal conditions (65.4% versus 69.6%; P = .017). Under current local resources, older patient age (P < .001), longer time since symptom onset (P < .001), high center endovascular therapy volume (P < .001), high personal endovascular therapy volume (P = .005), and neurosurgeons (P < .001) were more likely to favor endovascular therapy. European respondents were less likely to favor endovascular therapy (P = .001). Under assumed ideal conditions, older patient age (P < .001), longer time since symptom onset (P < .001), high center endovascular therapy volume (P = .041), high personal endovascular therapy volume (P = .002), and Asian respondents were more likely to favor endovascular therapy (P = .037). Respondents with more experience (P = .048) and high annual stroke thrombolysis treatment volume (P = .001) were less likely to favor endovascular therapy. Patients with M2 occlusions are considered appropriate candidates for endovascular therapy by most respondents in this survey, especially by those performing endovascular therapy more often and those practicing in high-volume centers.

Abstract WP263: Feasibility and Utility Of EEG for Estimating Infarct Volume During ER Assessment of Suspected Acute Stroke--A Pilot Study

Introduction: Endovascular therapy (EVT) improves outcomes in the setting of acute ischemic stroke (AIS) in a time-dependent manner, highlighting the need for improved methods to rapidly identify eligible patients, particularly in the pre-hospital setting. Current pre-hospital assessments are imprecise for this goal. Pre-hospital measurement of brain injury via EEG might provide additional useful diagnostic information regarding EVT eligibility. As a first step, the current study examined (1) feasibility of obtaining EEG early during ER assessment of patients with suspected AIS, and (2) EEG metrics predicting infarct volume. Methods: In subjects transported to the UC Irvine Medical Center for suspected AIS, a 3 min dense-array resting EEG was obtained during ED assessment. Results: EEG was acquired in 25 subjects (mean age 65 yr), 12 of whom were discharged with a diagnosis of radiologically confirmed AIS and 13 of whom were discharged with a non-stroke diagnosis. Median time from ED arrival to EEG = 114 min (and as early as 32 min after arrival), and time from last known well to EEG = 333 min. EEG was acquired in 24 subjects, with data lost due to human error in 1 subject. Among patients with AIS, median NIHSS score = 4 (range 0-19) and median infarct volume = 12 cc (range 0.3- 83). Infarct volume was found to correlate inversely with power in the low beta (13-19Hz) frequency range, bilaterally: larger infarcts were associated with reduced beta power in the leads over motor cortex (C3, C4) on the ipsilesional side (rho = -0.57, p=0.03) and on the contralesional side (rho = -0.60, p=0.02). Conclusions: The current findings support the potential of rapid EEG methods to identify patients with large infarcts who may be ideal candidates for EVT. Future studies will examine how well current findings extend to the pre-hospital setting, and how specific these EEG findings are for patients eligible for EVT.

Abstract WP49: Performance of CT, CTA, and MRI on Decision to Treat Emergent Large Vessel Occlusion (ELVO) in Patients who Present Greater Than 6 Hours After Stroke Onset

Background and purpose: We compared the value of Alberta Stroke Program Early Computed Tomographic scoring using CT (CT ASPECTS), collateral score on CT angiography (CTA), ASPECTS using diffusion-weighted MRI (DWI ASPECTS), DWI lesion volume, and DWI volume with National Institute of Health Stroke Scale (NIHSS) in determining candidacy of patients who presented &gt;6 hours from stroke onset. Methods: Decision to treat was first determined for each test alone and then with knowledge from other tests. A dismantling design was used to determine the additive effects of each test. Any discrepancy between the first and subsequent decisions to treat, in terms of sensitivity and specificity, is the impact of gained knowledge and was assessed using a generalized mixed-model assuming a binary distribution with PROC GLIMMIX/SAS. Inter-rater reliability was examined using weighted-Kappa. Results: We identified 39 patients between December 1st, 2015 and June 30th 2016. Median time from last-known normal to non-contrast CT was 492 minutes. Median interval between non-contrast CT and CTA was 7 minutes, and between CTA and MRI, 75.5 minutes. For sensitivity, effect of knowledge gained from successive tests was not significant (Table 1; Fig. 1). However, significant gains in specificity were observed from successive tests (63% to 84%; p&lt;.01). In particular, specificity increased by 14% (p=.09), 18% (p=.02), and 12% (p=.07), for DWI ASPECTS, DWI Volume, and DWI Volume+NIHSS, respectively. Inter-rater reliability was between .34-1.0 for each test. Conclusion: CT, CTA and MRI each have the ability to correctly determine ELVO patients who would be candidates for embolectomy. However, identification of poor candidates for endovascular therapy was significantly improved using diffusion-weighted MRI.

Abstract WP65: Relationship Between Neurological Severity and CBF Grade of Mr Perfusion in Acute Stroke Patients With the Carotid Artery Occlusion

Introduction: It remains unclear how strongly perfusion findings are related to neurological severity (NS) and MR-DW images (DWI). Hypothesis: CBF grade based on MR perfusion (MRp) is related to NS or DWI and can identify candidates for endovascular therapy (ET). Methods: Included in our retrospective analysis were acute ischemic stroke patients 1) who were admitted to our stroke center within 24 hours of the onset between Jan 2004 and May 2015, 2) who presented NIHSS as NS of 0 or more, 3) who underwent MRA, displaying complete occlusion of the affected carotid artery. We evaluated patients’ baseline features, NIHSS, DWI-ASPECTS (ACT) at arrival and CBF grade, which was calculated by using bilateral time-intensity curves (TICs) of MR perfusion. According to the time to peak (TP) and the peak signal (PS) comparing the affected side (a) with the contralateral side (c), we regarded the affected-sided PSa divided by TPa as possible CBFa and the contralateral-sided PSc divided by TPc as possible CBFc. CBF grade 1 was defined as CBFa divided by CBFc (CBF%) less than 0.2, grade 2 as CBF% of 0.2 or more and CBF% less than 0.7 and grade 3 as CBF% of 0.7 or more. Results: During the study period, 176 patients matched our criteria for analysis. Median NIHSS was 18, and median ACT was 6. There were 30 patients with CBF grade1, 81 with grade2 and 65 with grade3. Median NIHSS in grade1, 2, and 3 patients was 23, 19, and 7 (p&lt;0.0001), respectively, and there was a statistical significant difference between any grade groups (p&lt;0.016). Median ACT in grade1, 2, and 3 was 1, 5, and 8 (p&lt;0.0001), respectively, and there was a statistical significant difference between any grade groups (p&lt;0.016). Among 32 patients with NIHSS of 7 or less and ACT of 8 or more, there were 28 (87.5%) in grade3. Among 10 patients with NIHSS of 23 or more and ACT of 1 or less, there were 9 (90%) in grade1. Among 40 patients with NIHSS of 8 or more and ACT of 8 or more, there was 22 (55%) in grade2 and 18 (45%) in grade3. Conclusion: CBF grade defined by MRp had strong relation to NIHSS and ACT. Patients with lower NIHSS score but higher ACT score were probable candidates for ET and many among them belonged to CBF grade2.

Abstract WP62: Regional Leptomeningeal Score on TOF-MRA Predicts Collateral Flow Grade and Clinical Outcome in Patients with Acute Ischemic Stroke

Background: Collateral status at baseline is an important predictor of clinical outcome in patients with acute ischemic stroke (AIS). Non-contrast time-of-flight MR angiography (TOF-MRA) might provide information of blood flow features non-invasively. TOF-MRA could become a marker of collateral status and clinical outcome in patients with AIS. Methods: We retrospectively reviewed patients with AIS who had internal carotid artery or middle cerebral artery occlusion in three comprehensive stroke centers from August 2011 to July 2015. Those who underwent TOF-MRA sequence before endovascular therapy were investigated. Collateral status on TOF-MRA was graded by the previously-published regional leptomeningeal collateral (rLMC) score on CT angiography (0-20); collateral grade on angiography was assessed with the American Society of Interventional and Therapeutic Neuroradiology Collateral Grading System (0-4). We analyzed the relationship between rLMC score on TOF-MRA and patient characteristics, collateral flow grade, and good clinical outcome (modified Rankin Scale [mRS] of 0-2 at 90 days). Results: A total of 38 patients (aged 71.7 ± 10.3 years; men, 71%; NIHSS score, 20 ± 6; median DWI-ASPECTS, 8) were included. Collateral grade on angiography was 0 to 1 in 10 (26%) patients, 2 in 6 (15%), 3 in 19 (50%), and 4 in 3 (7%), which was correlated to rLMC score on TOF-MRA (p &lt; 0.001). Higher rLMC score on TOF-MRA was not related to baseline DWI-ASPECTS and reperfusion (Thrombolysis in Cerebral Infraction [TICI] 2b/3) after endovascular treatment, but was related to mRS 0-2 at 90 days (p = 0.021). All patients with high rLMC score (15-20) demonstrated mRS 0-2 at 90 days, whereas 69% of those with medium rLMC score (8-14) and 31% of those with low rLMC score did. In multivariate analysis, both rLMC score on TOF-MRA (OR, 1.5 per 1 point; p = 0.009) and reperfusion (TICI 2b/3 reperfusion; OR, 49.9; p &lt; 0.001) were independent predictors of mRS 0-2 at 90 days. Conclusions: rLMC score on TOF-MRA is a noninvasive and feasible parameter of collateral flow status and related to clinical outcome in patients with AIS. TOF-MRA might be a useful non-invasive imaging method to select candidates for endovascular therapy.

TU-AB-204-02: Advances in C-Arm CBCT for Cardiac Interventions

This symposium highlights advanced cone-beam CT (CBCT) technologies in four areas of emerging application in diagnostic imaging and image-guided interventions. Each area includes research that extends the spatial, temporal, and/or contrast resolution characteristics of CBCT beyond conventional limits through advances in scanner technology, acquisition protocols, and 3D image reconstruction techniques. Dr. G. Chen (University of Wisconsin) will present on the topic: Advances in C-arm CBCT for Brain Perfusion Imaging. Stroke is a leading cause of death and disability, and a fraction of people having an acute ischemic stroke are suitable candidates for endovascular therapy. Critical factors that affect both the likelihood of successful revascularization and good clinical outcome are: 1) the time between stroke onset and revascularization; and 2) the ability to distinguish patients who have a small volume of irreversibly injured brain (ischemic core) and a large volume of ischemic but salvageable brain (penumbra) from patients with a large ischemic core and little or no penumbra. Therefore, “time is brain” in the care of the stroke patients. C-arm CBCT systems widely available in angiography suites have the potential to generate non-contrast-enhanced CBCT images to exclude the presence of hemorrhage, time-resolved CBCT angiography to evaluate the site of occlusion and collaterals, and CBCT perfusion parametric images to assess the extent of the ischemic core and penumbra, thereby fulfilling the imaging requirements of a “one-stop-shop” in the angiography suite to reduce the time between onset and revascularization therapy. The challenges and opportunities to advance CBCT technology to fully enable the one-stop-shop C-arm CBCT platform for brain imaging will be discussed. Dr. R. Fahrig (Stanford University) will present on the topic: Advances in C-arm CBCT for Cardiac Interventions. With the goal of providing functional information during cardiac interventions, significant effort has been expended to improve the quantitative accuracy of C-arm CBCT reconstructions. The challenge is to improve image quality while providing very short turnaround between data acquisition and volume data visualization. Corrections for x-ray scatter, view aliasing and patient motion that require no more than 2 iterations keep processing time short while reducing artifact. Fast, multi-sweep acquisitions can be used to permit assessment of left ventricular function, and visualization of radiofrequency lesions created to treat arrhythmias. Workflows for each imaging goal have been developed and validated against gold standard clinical CT or histology. The challenges, opportunities, and limitations of the new functional C-arm CBCT imaging techniques will be discussed. Dr. W. Zbijewski (Johns Hopkins University) will present on the topic: Advances in CBCT for Orthopaedics and Bone Health Imaging. Cone-beam CT is particularly well suited for imaging of musculoskeletal extremities. Owing to the high spatial resolution of flat-panel detectors, CBCT can surpass conventional CT in imaging tasks involving bone visualization, quantitative analysis of subchondral trabecular structure, and visualization and monitoring of subtle fractures that are common in orthopedic radiology. A dedicated CBCT platform has been developed that offers flexibility in system design and provides not only a compact configuration with improved logistics for extremities imaging but also enables novel diagnostic capabilities such as imaging of weight-bearing lower extremities in a natural stance. The design, development and clinical performance of dedicated extremities CBCT systems will be presented. Advanced capabilities for quantitative volumetric assessment of joint space morphology, dual-energy image-based quantification of bone composition, and in-vivo analysis of bone microarchitecture will be discussed, along with emerging applications in the diagnosis of arthritis and osteoporosis and assessment of novel therapies. Finally, Dr. J. Boone (UC Davis) will present on the topic: Advances in CBCT for Breast Imaging. Breast CT has been studied as an imaging tool for diagnostic breast evaluation and for potential breast cancer screening. The breast CT application lends itself to CBCT because of the small dimensions of the breast, the tapered shape of the breast towards higher cone angle, and the fact that there are no bones in the breast. The performance of various generations of breast CT scanners developed in recent years will be discussed, focusing on advances in spatial resolution and image noise characteristics. The results will also demonstrate the results of clinical trials using both computer and human observers. Learning Objectives: Understand the challenges, key technological advances, and emerging opportunities of CBCT in: 1. Brain perfusion imaging, including assessment of ischemic stroke 2. Cardiac imaging for functional assessment in cardiac interventions 3. Orthopedics imaging for evaluation of musculoskeletal trauma, arthritis, and osteoporosis 4. Breast imaging for screening and diagnosis of breast cancer. Work presented in this symposium includes research support by: Siemens Healthcare (Dr. Chen); NIH and Siemens Healthcare (Dr. Fahrig); NIH and Carestream Health (Dr. Zbijewski); and NIH (Dr. Boone).

TU-AB-204-01: Advances in C-Arm CBCT for Brain Perfusion Imaging

This symposium highlights advanced cone-beam CT (CBCT) technologies in four areas of emerging application in diagnostic imaging and image-guided interventions. Each area includes research that extends the spatial, temporal, and/or contrast resolution characteristics of CBCT beyond conventional limits through advances in scanner technology, acquisition protocols, and 3D image reconstruction techniques. Dr. G. Chen (University of Wisconsin) will present on the topic: Advances in C-arm CBCT for Brain Perfusion Imaging. Stroke is a leading cause of death and disability, and a fraction of people having an acute ischemic stroke are suitable candidates for endovascular therapy. Critical factors that affect both the likelihood of successful revascularization and good clinical outcome are: 1) the time between stroke onset and revascularization; and 2) the ability to distinguish patients who have a small volume of irreversibly injured brain (ischemic core) and a large volume of ischemic but salvageable brain (penumbra) from patients with a large ischemic core and little or no penumbra. Therefore, “time is brain” in the care of the stroke patients. C-arm CBCT systems widely available in angiography suites have the potential to generate non-contrast-enhanced CBCT images to exclude the presence of hemorrhage, time-resolved CBCT angiography to evaluate the site of occlusion and collaterals, and CBCT perfusion parametric images to assess the extent of the ischemic core and penumbra, thereby fulfilling the imaging requirements of a “one-stop-shop” in the angiography suite to reduce the time between onset and revascularization therapy. The challenges and opportunities to advance CBCT technology to fully enable the one-stop-shop C-arm CBCT platform for brain imaging will be discussed. Dr. R. Fahrig (Stanford University) will present on the topic: Advances in C-arm CBCT for Cardiac Interventions. With the goal of providing functional information during cardiac interventions, significant effort has been expended to improve the quantitative accuracy of C-arm CBCT reconstructions. The challenge is to improve image quality while providing very short turnaround between data acquisition and volume data visualization. Corrections for x-ray scatter, view aliasing and patient motion that require no more than 2 iterations keep processing time short while reducing artifact. Fast, multi-sweep acquisitions can be used to permit assessment of left ventricular function, and visualization of radiofrequency lesions created to treat arrhythmias. Workflows for each imaging goal have been developed and validated against gold standard clinical CT or histology. The challenges, opportunities, and limitations of the new functional C-arm CBCT imaging techniques will be discussed. Dr. W. Zbijewski (Johns Hopkins University) will present on the topic: Advances in CBCT for Orthopaedics and Bone Health Imaging. Cone-beam CT is particularly well suited for imaging of musculoskeletal extremities. Owing to the high spatial resolution of flat-panel detectors, CBCT can surpass conventional CT in imaging tasks involving bone visualization, quantitative analysis of subchondral trabecular structure, and visualization and monitoring of subtle fractures that are common in orthopedic radiology. A dedicated CBCT platform has been developed that offers flexibility in system design and provides not only a compact configuration with improved logistics for extremities imaging but also enables novel diagnostic capabilities such as imaging of weight-bearing lower extremities in a natural stance. The design, development and clinical performance of dedicated extremities CBCT systems will be presented. Advanced capabilities for quantitative volumetric assessment of joint space morphology, dual-energy image-based quantification of bone composition, and in-vivo analysis of bone microarchitecture will be discussed, along with emerging applications in the diagnosis of arthritis and osteoporosis and assessment of novel therapies. Finally, Dr. J. Boone (UC Davis) will present on the topic: Advances in CBCT for Breast Imaging. Breast CT has been studied as an imaging tool for diagnostic breast evaluation and for potential breast cancer screening. The breast CT application lends itself to CBCT because of the small dimensions of the breast, the tapered shape of the breast towards higher cone angle, and the fact that there are no bones in the breast. The performance of various generations of breast CT scanners developed in recent years will be discussed, focusing on advances in spatial resolution and image noise characteristics. The results will also demonstrate the results of clinical trials using both computer and human observers. Learning Objectives: Understand the challenges, key technological advances, and emerging opportunities of CBCT in: 1. Brain perfusion imaging, including assessment of ischemic stroke 2. Cardiac imaging for functional assessment in cardiac interventions 3. Orthopedics imaging for evaluation of musculoskeletal trauma, arthritis, and osteoporosis 4. Breast imaging for screening and diagnosis of breast cancer. Work presented in this symposium includes research support by: Siemens Healthcare (Dr. Chen); NIH and Siemens Healthcare (Dr. Fahrig); NIH and Carestream Health (Dr. Zbijewski); and NIH (Dr. Boone).

TU-AB-204-04: Advances in CBCT for Breast Imaging

This symposium highlights advanced cone-beam CT (CBCT) technologies in four areas of emerging application in diagnostic imaging and image-guided interventions. Each area includes research that extends the spatial, temporal, and/or contrast resolution characteristics of CBCT beyond conventional limits through advances in scanner technology, acquisition protocols, and 3D image reconstruction techniques. Dr. G. Chen (University of Wisconsin) will present on the topic: Advances in C-arm CBCT for Brain Perfusion Imaging. Stroke is a leading cause of death and disability, and a fraction of people having an acute ischemic stroke are suitable candidates for endovascular therapy. Critical factors that affect both the likelihood of successful revascularization and good clinical outcome are: 1) the time between stroke onset and revascularization; and 2) the ability to distinguish patients who have a small volume of irreversibly injured brain (ischemic core) and a large volume of ischemic but salvageable brain (penumbra) from patients with a large ischemic core and little or no penumbra. Therefore, “time is brain” in the care of the stroke patients. C-arm CBCT systems widely available in angiography suites have the potential to generate non-contrast-enhanced CBCT images to exclude the presence of hemorrhage, time-resolved CBCT angiography to evaluate the site of occlusion and collaterals, and CBCT perfusion parametric images to assess the extent of the ischemic core and penumbra, thereby fulfilling the imaging requirements of a “one-stop-shop” in the angiography suite to reduce the time between onset and revascularization therapy. The challenges and opportunities to advance CBCT technology to fully enable the one-stop-shop C-arm CBCT platform for brain imaging will be discussed. Dr. R. Fahrig (Stanford University) will present on the topic: Advances in C-arm CBCT for Cardiac Interventions. With the goal of providing functional information during cardiac interventions, significant effort has been expended to improve the quantitative accuracy of C-arm CBCT reconstructions. The challenge is to improve image quality while providing very short turnaround between data acquisition and volume data visualization. Corrections for x-ray scatter, view aliasing and patient motion that require no more than 2 iterations keep processing time short while reducing artifact. Fast, multi-sweep acquisitions can be used to permit assessment of left ventricular function, and visualization of radiofrequency lesions created to treat arrhythmias. Workflows for each imaging goal have been developed and validated against gold standard clinical CT or histology. The challenges, opportunities, and limitations of the new functional C-arm CBCT imaging techniques will be discussed. Dr. W. Zbijewski (Johns Hopkins University) will present on the topic: Advances in CBCT for Orthopaedics and Bone Health Imaging. Cone-beam CT is particularly well suited for imaging of musculoskeletal extremities. Owing to the high spatial resolution of flat-panel detectors, CBCT can surpass conventional CT in imaging tasks involving bone visualization, quantitative analysis of subchondral trabecular structure, and visualization and monitoring of subtle fractures that are common in orthopedic radiology. A dedicated CBCT platform has been developed that offers flexibility in system design and provides not only a compact configuration with improved logistics for extremities imaging but also enables novel diagnostic capabilities such as imaging of weight-bearing lower extremities in a natural stance. The design, development and clinical performance of dedicated extremities CBCT systems will be presented. Advanced capabilities for quantitative volumetric assessment of joint space morphology, dual-energy image-based quantification of bone composition, and in-vivo analysis of bone microarchitecture will be discussed, along with emerging applications in the diagnosis of arthritis and osteoporosis and assessment of novel therapies. Finally, Dr. J. Boone (UC Davis) will present on the topic: Advances in CBCT for Breast Imaging. Breast CT has been studied as an imaging tool for diagnostic breast evaluation and for potential breast cancer screening. The breast CT application lends itself to CBCT because of the small dimensions of the breast, the tapered shape of the breast towards higher cone angle, and the fact that there are no bones in the breast. The performance of various generations of breast CT scanners developed in recent years will be discussed, focusing on advances in spatial resolution and image noise characteristics. The results will also demonstrate the results of clinical trials using both computer and human observers. Learning Objectives: Understand the challenges, key technological advances, and emerging opportunities of CBCT in: 1. Brain perfusion imaging, including assessment of ischemic stroke 2. Cardiac imaging for functional assessment in cardiac interventions 3. Orthopedics imaging for evaluation of musculoskeletal trauma, arthritis, and osteoporosis 4. Breast imaging for screening and diagnosis of breast cancer. Work presented in this symposium includes research support by: Siemens Healthcare (Dr. Chen); NIH and Siemens Healthcare (Dr. Fahrig); NIH and Carestream Health (Dr. Zbijewski); and NIH (Dr. Boone).

TU-AB-204-03: Advances in CBCT for Orhtopaedics and Bone Health Imaging

This symposium highlights advanced cone-beam CT (CBCT) technologies in four areas of emerging application in diagnostic imaging and image-guided interventions. Each area includes research that extends the spatial, temporal, and/or contrast resolution characteristics of CBCT beyond conventional limits through advances in scanner technology, acquisition protocols, and 3D image reconstruction techniques. Dr. G. Chen (University of Wisconsin) will present on the topic: Advances in C-arm CBCT for Brain Perfusion Imaging. Stroke is a leading cause of death and disability, and a fraction of people having an acute ischemic stroke are suitable candidates for endovascular therapy. Critical factors that affect both the likelihood of successful revascularization and good clinical outcome are: 1) the time between stroke onset and revascularization; and 2) the ability to distinguish patients who have a small volume of irreversibly injured brain (ischemic core) and a large volume of ischemic but salvageable brain (penumbra) from patients with a large ischemic core and little or no penumbra. Therefore, “time is brain” in the care of the stroke patients. C-arm CBCT systems widely available in angiography suites have the potential to generate non-contrast-enhanced CBCT images to exclude the presence of hemorrhage, time-resolved CBCT angiography to evaluate the site of occlusion and collaterals, and CBCT perfusion parametric images to assess the extent of the ischemic core and penumbra, thereby fulfilling the imaging requirements of a “one-stop-shop” in the angiography suite to reduce the time between onset and revascularization therapy. The challenges and opportunities to advance CBCT technology to fully enable the one-stop-shop C-arm CBCT platform for brain imaging will be discussed. Dr. R. Fahrig (Stanford University) will present on the topic: Advances in C-arm CBCT for Cardiac Interventions. With the goal of providing functional information during cardiac interventions, significant effort has been expended to improve the quantitative accuracy of C-arm CBCT reconstructions. The challenge is to improve image quality while providing very short turnaround between data acquisition and volume data visualization. Corrections for x-ray scatter, view aliasing and patient motion that require no more than 2 iterations keep processing time short while reducing artifact. Fast, multi-sweep acquisitions can be used to permit assessment of left ventricular function, and visualization of radiofrequency lesions created to treat arrhythmias. Workflows for each imaging goal have been developed and validated against gold standard clinical CT or histology. The challenges, opportunities, and limitations of the new functional C-arm CBCT imaging techniques will be discussed. Dr. W. Zbijewski (Johns Hopkins University) will present on the topic: Advances in CBCT for Orthopaedics and Bone Health Imaging. Cone-beam CT is particularly well suited for imaging of musculoskeletal extremities. Owing to the high spatial resolution of flat-panel detectors, CBCT can surpass conventional CT in imaging tasks involving bone visualization, quantitative analysis of subchondral trabecular structure, and visualization and monitoring of subtle fractures that are common in orthopedic radiology. A dedicated CBCT platform has been developed that offers flexibility in system design and provides not only a compact configuration with improved logistics for extremities imaging but also enables novel diagnostic capabilities such as imaging of weight-bearing lower extremities in a natural stance. The design, development and clinical performance of dedicated extremities CBCT systems will be presented. Advanced capabilities for quantitative volumetric assessment of joint space morphology, dual-energy image-based quantification of bone composition, and in-vivo analysis of bone microarchitecture will be discussed, along with emerging applications in the diagnosis of arthritis and osteoporosis and assessment of novel therapies. Finally, Dr. J. Boone (UC Davis) will present on the topic: Advances in CBCT for Breast Imaging. Breast CT has been studied as an imaging tool for diagnostic breast evaluation and for potential breast cancer screening. The breast CT application lends itself to CBCT because of the small dimensions of the breast, the tapered shape of the breast towards higher cone angle, and the fact that there are no bones in the breast. The performance of various generations of breast CT scanners developed in recent years will be discussed, focusing on advances in spatial resolution and image noise characteristics. The results will also demonstrate the results of clinical trials using both computer and human observers. Learning Objectives: Understand the challenges, key technological advances, and emerging opportunities of CBCT in: 1. Brain perfusion imaging, including assessment of ischemic stroke 2. Cardiac imaging for functional assessment in cardiac interventions 3. Orthopedics imaging for evaluation of musculoskeletal trauma, arthritis, and osteoporosis 4. Breast imaging for screening and diagnosis of breast cancer. Work presented in this symposium includes research support by: Siemens Healthcare (Dr. Chen); NIH and Siemens Healthcare (Dr. Fahrig); NIH and Carestream Health (Dr. Zbijewski); and NIH (Dr. Boone).

TU-AB-204-00: Advances in Cone-Beam CT and Emerging Applications

This symposium highlights advanced cone-beam CT (CBCT) technologies in four areas of emerging application in diagnostic imaging and image-guided interventions. Each area includes research that extends the spatial, temporal, and/or contrast resolution characteristics of CBCT beyond conventional limits through advances in scanner technology, acquisition protocols, and 3D image reconstruction techniques. Dr. G. Chen (University of Wisconsin) will present on the topic: Advances in C-arm CBCT for Brain Perfusion Imaging. Stroke is a leading cause of death and disability, and a fraction of people having an acute ischemic stroke are suitable candidates for endovascular therapy. Critical factors that affect both the likelihood of successful revascularization and good clinical outcome are: 1) the time between stroke onset and revascularization; and 2) the ability to distinguish patients who have a small volume of irreversibly injured brain (ischemic core) and a large volume of ischemic but salvageable brain (penumbra) from patients with a large ischemic core and little or no penumbra. Therefore, “time is brain” in the care of the stroke patients. C-arm CBCT systems widely available in angiography suites have the potential to generate non-contrast-enhanced CBCT images to exclude the presence of hemorrhage, time-resolved CBCT angiography to evaluate the site of occlusion and collaterals, and CBCT perfusion parametric images to assess the extent of the ischemic core and penumbra, thereby fulfilling the imaging requirements of a “one-stop-shop” in the angiography suite to reduce the time between onset and revascularization therapy. The challenges and opportunities to advance CBCT technology to fully enable the one-stop-shop C-arm CBCT platform for brain imaging will be discussed. Dr. R. Fahrig (Stanford University) will present on the topic: Advances in C-arm CBCT for Cardiac Interventions. With the goal of providing functional information during cardiac interventions, significant effort has been expended to improve the quantitative accuracy of C-arm CBCT reconstructions. The challenge is to improve image quality while providing very short turnaround between data acquisition and volume data visualization. Corrections for x-ray scatter, view aliasing and patient motion that require no more than 2 iterations keep processing time short while reducing artifact. Fast, multi-sweep acquisitions can be used to permit assessment of left ventricular function, and visualization of radiofrequency lesions created to treat arrhythmias. Workflows for each imaging goal have been developed and validated against gold standard clinical CT or histology. The challenges, opportunities, and limitations of the new functional C-arm CBCT imaging techniques will be discussed. Dr. W. Zbijewski (Johns Hopkins University) will present on the topic: Advances in CBCT for Orthopaedics and Bone Health Imaging. Cone-beam CT is particularly well suited for imaging of musculoskeletal extremities. Owing to the high spatial resolution of flat-panel detectors, CBCT can surpass conventional CT in imaging tasks involving bone visualization, quantitative analysis of subchondral trabecular structure, and visualization and monitoring of subtle fractures that are common in orthopedic radiology. A dedicated CBCT platform has been developed that offers flexibility in system design and provides not only a compact configuration with improved logistics for extremities imaging but also enables novel diagnostic capabilities such as imaging of weight-bearing lower extremities in a natural stance. The design, development and clinical performance of dedicated extremities CBCT systems will be presented. Advanced capabilities for quantitative volumetric assessment of joint space morphology, dual-energy image-based quantification of bone composition, and in-vivo analysis of bone microarchitecture will be discussed, along with emerging applications in the diagnosis of arthritis and osteoporosis and assessment of novel therapies. Finally, Dr. J. Boone (UC Davis) will present on the topic: Advances in CBCT for Breast Imaging. Breast CT has been studied as an imaging tool for diagnostic breast evaluation and for potential breast cancer screening. The breast CT application lends itself to CBCT because of the small dimensions of the breast, the tapered shape of the breast towards higher cone angle, and the fact that there are no bones in the breast. The performance of various generations of breast CT scanners developed in recent years will be discussed, focusing on advances in spatial resolution and image noise characteristics. The results will also demonstrate the results of clinical trials using both computer and human observers. Learning Objectives: Understand the challenges, key technological advances, and emerging opportunities of CBCT in: 1. Brain perfusion imaging, including assessment of ischemic stroke 2. Cardiac imaging for functional assessment in cardiac interventions 3. Orthopedics imaging for evaluation of musculoskeletal trauma, arthritis, and osteoporosis 4. Breast imaging for screening and diagnosis of breast cancer. Work presented in this symposium includes research support by: Siemens Healthcare (Dr. Chen); NIH and Siemens Healthcare (Dr. Fahrig); NIH and Carestream Health (Dr. Zbijewski); and NIH (Dr. Boone).

Abstract TP28: Combining Clinical with Radiographic Criteria to Select Patients for Endovascular Therapy in Acute Stroke

BACKGROUND: Patient selection is emerging as an important aspect of interventional treatment of acute ischemic stroke. The baseline CT scan and NIHSS can be performed very quickly to identify those patients who will have proximal arterial occlusions (PAOs) amenable to endovascular therapy. Hyperdense arteries (HDAs) identified on thin-slice reconstruction (0.625 mm slice) CT have been shown to predict PAOs on CT Angiography. We sought to determine whether the combination of clinical (NIHSS strata) and radiographic (standard 5mm slice non-contrast head CT) criteria could better identify ideal candidates for endovascular therapy. METHODS: We reviewed IMS I and II subjects who were treated with IV tPA for an anterior circulation stroke, and had a baseline standard head CT followed by a digital subtraction angiogram (DSA; n = 144 of the 161 patients in IMS I and II). Stroke severity (NIHSS 10-19, or ≥20), presence of a HDA on baseline CT (either in the ICA terminus or M1 branch of the MCA), and the location of arterial occlusions (either partial or complete) on DSA were determined. We calculated sensitivity, specificity and the positive predictive value (PPV) of stroke severity and a HDA for the presence of a PAO (ICA, M1 or M2 branches of MCA). RESULTS: 64 of 144 patients (44%) had a NIHSS ≥20. 74 of 144 patients (51%) had a HDA on CT (39 patients or 49% with NIHSS 10-19; 35 patients or 55% with NIHSS ≥20). After IV tPA, a PAO was seen on DSA in 105 (73%) of patients. DSA showed distal or no occlusion in 39 patients (13 of whom had a HDA on CT). The PPV of a HDA for a PAO was 82% (95%CI = 72-90%; sens = 58%, spec = 67%), whereas the PPV of NIHSS ≥20 for a PAO was 78% (95%CI = 66-87%; sens = 48%, spec = 64%). In patients with a HDA, consideration of stroke severity (NIHSS ≥20) only improved the PPV for a PAO to 86% (95%CI = 70-95%; sens = 60%, spec = 31%). In those with a HDA and a less severe stroke (NIHSS 10-19), PPV was 79% (95%CI = 63-91%; sens = 56%, spec = 68%). CONCLUSIONS: In patients with acute anterior circulation ischemic stroke, adding stroke severity does not appear to significantly improve the predictive value of a hyperdense artery on baseline standard CT for the presence of a proximal arterial occlusion after IV t-PA. Further study is needed to identify patients who are candidates for endovascular therapy.

Abstract 3070: Assessment of Manual Aspiration Therapy for the Treatment of Sinus Thrombosis

Objective: While hydration and anticoagulation is typically the standard of care for cerebral venous sinus thrombosis, some patients remain refractory to medical management and continue to deteriorate. In these instances a number of more aggressive endovascular techniques have been reported to remove clots and restore blood flow in the venous sinuses. These techniques include direct thrombolysis, angioplasty, and various methods to disrupt and aspirate clot. Here we present the technique of endovascular transvenous manual aspiration thrombectomy (MAT) in five patients. Methods: We reviewed the records of five patients with medically refractory cerebral venous sinus thrombosis who received transvenous MAT. Presentation, technique, and outcome were evaluated. Results: Out of the five cases reviewed presentation included vomiting, dehydration, mental status changes, headaches, and acute motor deficits. On imaging three of the five patients had hemorrhage, edema, and mass effect present before treatment, while two had edema only. All of the patients reviewed were treated with anticoagulation therapy, intravenous heparin or subcutaneous lovenox, for a minimum of 24 hours. However, all of the patients continued to deteriorate despite early and aggressive medical anticoagulation therapy. All of the patients demonstrated rapid and progressive worsening of their neurological exam pre-operatively, including lack of arousal, pathological posturing, and expansion of secondary hemorrhages. This rapid deterioration warranted aggressive intervention, making the patients candidates for endovascular therapy. Direct thrombolysis with tPA was utilized with MAT via a distal access catheter(DAC) in all but one patient in which tPA was not used due to concern for hemorrhage. Aspiration of the superior sagittal sinus, transverse sinuses, straight sinus, and internal jugular were all included in this series. Catheters included the 0.070, 0.057, and 0.044 DAC and the 0.054 Penumbra microcatheter. Revascularization was achieved in all instances. One patient presented and remained neurologically devastated. She died 5 days after treatment. All other patients experienced improvement in their neurological examinations and were eventually discharged from the hospital in stable condition. Conclusions: Endovascular transvenous MAT is a feasible and effective revascularization technique to treat patients with cerebral venous sinus thrombosis.

Abstract 2261: Presence of Large Deep White Matter Lesion May Predict Futile Recanalization in Endovascular Therapy for Acute Ischemic Stroke

Background: A subset of stroke patients treated with endovascular recanalization therapy suffers poor outcome despite good arterial recanalization. The aim of this study is to identify whether large ischemic lesion in deep white matter (DWM) on diffusion weighted imaging (DWI) prior to therapy predicts futile recanalization. Method: Consecutive acute stroke patients with anterior circulation ischemia whose artery had been recanalized at Thrombolysis in Myocardial Infarct (TIMI) flow grade 2 or 3 following endovascular therapy were included. All patients underwent CT and MRI before endovascular therapy. We defined large DWI - DWM lesion if DWI showed the hyperintense lesion in the DWM which mostly extended between anterior and posterior horn of the lateral ventricle. We identified Alberta Stroke Program Early CT Scores (ASPECTS) of CT and DWI, and volumes measured on initial DWI and mean transit time of perfusion weighted images. We assessed the prevalence of TIMI grade 3 recanalization and parenchymal hemorrhage type 2, and final ischemic lesion volume after endovascular therapy. Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) score. Futile recanalization was defined as a 30-day modified Rankin Scale score 3 to 6 despite recanalization at TIMI grade 2 or 3. Univariate and multivariate regression analyses were performed to identify predictors of futile recanalization. Results: Partial or complete recanalization (TIMI grade 2 or 3) was observed in 35 of 46 patients (76 %). Of the 35 patients, futile recanalization was observed in 20 patients (57 %). Patients with futile recanalization had older age (median, 74 versus 58 years old, p = 0.053), higher initial NIHSS score (median, 17 versus 9, p = 0.042), pre-treatment large DWI - DWM lesion (45 versus 9 %, p = 0.022), and larger final ischemic lesion volume (median, 37 versus 9 ml, p = 0.003). ASPECTS of CT (median, 9 versus 9, p = 0.527) and DWI (median, 8 versus 8, p = 0.943) and initial ischemic lesion volumes on DWI (median, 21 versus 14 ml, p = 0.230) and on mean transit time (median, 189 versus 192 ml, p = 0.976) did not demonstrate statistically significance between patients with and without futile recanalization. There were also no significant differences between the outcome groups in times from stroke onset to imaging or endovascular therapy. Logistic regression analysis demonstrated that large DWI - DWM lesion was an independent predictor of futile recanalization (OR 10.40, 95 % CI 1.03 to 105.21, p = 0.047). Conclusion: Patients who have large pre-treatment DWI - DWM lesion may be poor candidates for endovascular therapy.