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Purpose: To assess acute ischemic stroke (AIS) severity, infarct is segmented using computed tomography perfusion (CTP) software, such as RAPID, Sphere, and Vitrea, relying on contralateral hemisphere thresholds. Since this approach is potentially patient dependent, we investigated whether convolutional neural networks (CNNs) could achieve better performances without the need for contralateral hemisphere thresholds. Approach: CTP and diffusion-weighted imaging (DWI) data were retrospectively collected for 63 AIS patients. Cerebral blood flow (CBF), cerebral blood volume (CBV), time-to-peak, mean-transit-time (MTT), and delay time maps were generated using Vitrea CTP software. U-net shaped CNNs were developed, trained, and tested for 26 different input CTP parameter combinations. Infarct labels were segmented from DWI volumes registered with CTP volumes. Infarct volumes were reconstructed from two-dimensional CTP infarct segmentations. To remove erroneous segmentations, conditional random field (CRF) postprocessing was applied and compared with prior results. Spatial and volumetric infarct agreement was assessed between DWI and CTP (CNNs and commercial software) using median infarct difference, median absolute error, dice coefficient, positive predictive value. Results: The most accurate combination of parameters for CNN segmenting infarct using CRF postprocessing was CBF, CBV, and MTT (4.83 mL, 10.14 mL, 0.66, 0.73). Commercial software results are: RAPID = (2.25 mL, 21.48 mL, 0.63, 0.70), Sphere = (7.57 mL, 17.74 mL, 0.64, 0.70), Vitrea = (6.79 mL, 15.28 mL, 0.63, 0.72). Conclusions: Use of CNNs with multiple input perfusion parameters has shown to be accurate in segmenting infarcts and has the ability to improve clinical workflow by eliminating the need for contralateral hemisphere comparisons.

BackgroundFew studies have compared technical success and effectiveness of transradial access (TRA) versus transfemoral access (TFA) for mechanical thrombectomy (MT) for acute ischemic stroke (AIS). We compared the two approaches for technical success, effectiveness, and outcomes.MethodsWe retrospectively compared TRA with TFA for AIS MT at our institute. We additionally performed a systematic review and meta-analysis of studies describing the use of TRA alone or in comparison with TFA for MT. Primary outcomes included rate of successful reperfusion (thrombolysis in cerebral infarction (TICI)>2b), number of passes, access-site complications, and 3- month mortality and favorable functional outcomes (modified Rankin Scale (mRS) score 0–2).ResultsA total of 222 consecutive patients (TRA=93, TFA=129) were included in our case series. The rate of successful reperfusion was significantly higher for the TFA cohort (91.4% vs 79.6%, P=0.01) with lower mean number of passes (1.8±1.2 vs 2.4±1.6, P=0.014). Three-month mortality in the TFA group was lower (22.1% vs 40.9% for the TRA cohort (P=0.004), with a higher rate of favorable functional outcomes (51.3% vs 34.1%, P=0.015). A meta-analysis of 10 studies showed significant heterogeneity in rates of successful reperfusion (57.1% to 95.6%, heterogeneity=67.55%, P=0.001). None of the previous comparative studies reported 3-month mortality and functional outcomes.ConclusionsThis case series demonstrate a higher successful reperfusion rate, fewer passes, lower 3-month mortality, and improved 3-month functional outcomes with TFA. The systematic review highlights the inadequacy of existing evidence. Prospective comparative studies are needed before a ‘radial-first’ approach can be adopted for stroke intervention.

Objectives Cost-effectiveness of endovascular therapy (EVT) is a key consideration for broad use of this approach for emergent large vessel occlusion stroke. We evaluated the evidence on cost-effectiveness of EVT in comparison with best medical management from a global perspective. Materials and Methods This systematic review of studies published between January 2010 and May 2020 evaluated the cost effectiveness of EVT for patients with large vessel occlusion acute ischemic stroke. The gain in quality adjusted life year (QALY) and incremental cost-effectiveness ratio (ICER), expressed as cost per QALY resulting from EVT, were recorded. The study setting (country, economic perspective), decision model, and data sources used in economic models of EVT cost-effectiveness were recorded. Results Twenty-five original studies from 12 different countries were included in our review. Five of these studies were reported from a societal perspective; 18 were reported from a healthcare system perspective. Two studies used real-world data. The time horizon varied from 1 year to a lifetime; however, 18 studies reported a time horizon of >10 years. Twenty studies reported using outcome data from randomized, controlled clinical trials for their models. Nineteen studies reported using a Markov model. Incremental QALYs ranged from 0.09–3.5. All studies but 1 reported that EVT was cost-effective. Conclusions Evidence from different countries and economic perspectives suggests that EVT for stroke treatment is cost-effective. Most cost-effectiveness studies are based on outcome data from randomized clinical trials. However, there is a need to study the cost-effectiveness of EVT based solely on real-world outcome data.

Medial sphenoid wing meningiomas constitute up to 10% of all intracranial meningiomas.(1) These meningiomas have a tendency to engulf the internal carotid artery (ICA), its termination, and the middle cerebral artery. These arteries and the optic apparatus are at a particularly high risk of injury during the microsurgical resection of these tumors. ICA injuries are potentially devastating and challenging to manage. In this technical video, we demonstrate the management of inadvertent ICA terminus injury during the microsurgical resection of the medial sphenoid. Rapid vascular control was obtained with temporary clips on the ICA and anterior cerebral artery (ACA). Tamponade with a felt and primary repair of the arterial tear were attempted without success. We then created a tamponade around the tear with the help of a Hemashield strip (Meadox Medicals, Oakland, New Jersey), which was secured with a 90-degree-angled clip. Temporary clips were removed, and microsurgical dissection was completed. The Hemashield strip was removed at the end of the procedure. This maneuver resulted in complete hemostasis. Vascular patency was confirmed using Doppler imaging and intraoperative indocyanine green angiography. Postoperatively, the patient had transient right-sided weakness, which resolved 2 d later. The patient was discharged without any neurological deficit. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Video ©University at Buffalo, April 2020. Published with permission.

Introduction Middle meningeal artery (MMA) embolization for the treatment of subacute/chronic subdural hematoma (cSDH) is an emerging therapy for minimally invasive treatment of subdural blood products. Trans radial access (TRA) may offer certain benefits to this patient population who are often on blood thinners with multiple comorbid medical issues. Methods 46 consecutive patients between 2018 and January of 2020 undergoing trans radial access for MMA embolization with Onyx were analyzed from a single center prospectively maintained database. Patient demographics, comorbidities, ambulatory times, subdural resorption status, and guide catheter type were recorded. We specifically looked at conversion to femoral access and complication rates from access for this series. Multivariate analysis with SPSS version 25 was utilized. Results 46 patients were included in this study. The average age was 71.7± 14 years. TRA was successful for MMA embolization in 44 patients (95%). There were no access site complications. The mean cSDH size was 14 ±5 mm. 5 patients had recurrent cSDH prior to undergoing MMA embolization (10.8%). 4 patients (8.7%) had adjuvant MMA embolization performed within 24 hrs of burr hole evacuation. Symptomatic improvement was seen in 88.6% of patients (39/44). Mean length of stay was 4 ±3 days, all patients previously ambulatory were ambulated immediately post procedure. 3 patients were appropriate for same day discharge. Mean followup was 8 weeks ± 4. 86.4% of patients had either resolution or partial resolution of the cSDH at mean follow-up. Univariate analysis revealed use of antiplatelet agents was associated with failed resorption of cSDH (83.3% vs 23%, P=0.009). Charlson comorbidity index, gender, age, and treatment approach (adjuvant vs primary) were not associated with failed resorption status. 48% of patients had a Charlson Comorbidity index >5. 91% of TRA embolizations were performed with a 6F 071 guide catheter. Conclusion MMA embolization with Onyx for cSDH appears to result in symptomatic and radiographic relief in the majority of patients. Trans radial access via 6F 071 guide catheter in this population with numerous comorbidities offers a safe and effective strategy for early ambulation and procedural success. Disclosures G. Rajah: None. M. Waqas: None. R. Dossani: None. A. Gong: None. K. Rho: None. S. Housley: None. H. Rai: None. F. Chin: None. M. Tso: None. E. Levy: None. A. Siddiqui: None. K. Snyder: None. J. Davies: None.

Background Diagnostic cerebral angiography (DSA) and neurointerventions have traditionally been performed via transfemoral access (TFA). The perception of a steep learning curve associated with transradial access (TRA) has limited adoption in neurointervention. This study compares the learning curves of transradial vs. transfemoral DSA in a cohort of neurointerventional fellows. Methods The first 150 consecutive radial and femoral DSA were identified for each fellow from a prospective neurointerventional registry from July 2017 to March 2020. Total fluoroscopy time and number of intracranial arteries injected were recorded. Mean fluoroscopy time per intracranial artery injected (termed angiographic efficiency) was calculated and was used as a surrogate measure of technical proficiency. Mean angiographic efficiencies were compared across partitions of 25 consecutive DSAs (e.g. 1–25, 26–50, 51–75, etc.). Results There were 607 radial DSA and 635 femoral DSA identified among 5 fellows. The overall angiographic efficiencies were not significantly different based on access site (radial mean 3.2 min, femoral mean 3.7 min, p>0.05). For 3 fellows without prior endovascular experience, technical proficiency was obtained between 25–50 femoral DSA procedures. Among these same fellows, one fellow achieved technical proficiency after 25–50 radial DSA procedures, while the other 2 fellows had flattened learning curves. There were 2 fellows that had no significant learning curve for either access type, but both had extensive experience with endovascular procedures prior to starting fellowship. Two patients (2/1342 = 0.1%) experienced transient neurologic symptoms post-procedure. Among 635 femoral DSA, there were 22 (3.5%) minor adverse events (14 small groin hematomas not requiring transfusion, 1 pseudoaneurysm, 7 non-flow-limiting dissections). Among 607 radial DSA, there were 3 (0.5%) minor adverse events (2 small forearm hematomas, 1 intraluminal wire removed with radial cut-down), which was significantly less than femoral DSA minor adverse events (p=0.0001). Radial to femoral conversion rate was 1.2% (7/607, 2 radial spasm, 2 unsuccessful radial artery access, 3 aberrant right subclavian artery). Femoral to radial conversion rate was 0.3% (2/635). From March 2019 to February 2020, the proportion of DSA performed via transradial access increased from 36% to 78% at our institution. Conclusion This study demonstrates the learning curves for both TRA and TFA diagnostic cerebral angiograms. Proficiency improves significantly with either type of access, typically requiring between 25–50 procedures. TRA DSA have significantly less access site complications than TFA DSA. Disclosures M. Tso: None. G. Rajah: None. R. Dossani: None. M. Meyer: None. M. McPheeters: None. K. Vakharia: None. M. Waqas: None. K. Snyder: None. E. Levy: None. A. Siddiqui: None. J. Davies: None.

Introduction The NAPA study was a prospective, multicenter, single-arm IDE trial of the PulseRider device as an adjunctive treatment in conjunction with coil embolization of unruptured wide-neck bifurcation aneurysms which was electively discontinued for reasons not related to the safety or performance of the device. We report on the available enrollments in NAPA and their available follow up. Methods The PulseRider device was implanted in 18/21 enrollments. Available core-lab adjudicated data from the first 18 implants is presented. Of those, 5 have one year follow up data available. Of the 3 device implantation failures, the locations included basilar (1), carotid terminus (1), and ACOMM (1). Results For the 18 patients with PulseRider implanted as a coil-adjunct device, the mean age was 60.7± 8.9 yrs and 16 were female. The mean aneurysm diameter was 6.6± 2.2 mm, height 5.3±1.7 mm and neck 4.8 ±1.5 mm. Locations included the basilar apex (11), MCA bifurcation (4) and ACOMM (3). Thirteen of 18 were de novo aneurysms while the remainder (5) were treated in the setting of aneurysmal recurrence. The most common PulseRider placement was extra-aneurysmal (12/18), followed by intra-aneurysmal (4/18) and hybrid (2/18). Immediate angiographic occlusions were 66.6% RR-I, 16.7% RR-II, 16.7% RR-III. There were no device related adverse events. There were 3 (16.7%) procedure-related adverse events which did not result in neurological changes. Seven enrollments have 6 month follow up and all are RRI-II. Only 1 has one year angiographic follow up (RRI) adjudicated by the core lab, and 4 have clinical follow up (4/4 mRS 0–2). None of the target aneurysms have required retreatment. Conclusions The results of the discontinued NAPA provide high quality data on the occlusion rates and safety profile for the PulseRider device. Further one year angiographic and clinical follow up will be reported when available. Disclosures A. Spiotta: 1; C; Microvention. 2; C; Minnetronix, Penumbra, Cerenovus. 6; C; Cerenovus, Penumbra, Pulsar Vascular, Stryker, Microvention. K. Ebersole: None. J. Lena: None. R. Starke: 2; C; Medtronic Neurovascular, Penumbra, Cerenovus, Abbott. R. De Leacy: 6; C; Penumbra, Cerenovus, Siemens. A. Puri: 1; C; Stryker Neurovascular, Medtronic Neurovascular. 2; C; Stryker Neurovascular, Medtronic Neurovascular. D. Yavagal: 2; C; Medtronic Neurovascular, Rapid Medical, Steering Committee, Neuralanalytics. 6; C; Medtronic, Cerenovus/Johnson & Johnson, Rapid Medical, Neuralanalytics. B. Bohnstedt: 2; C; Penumbra, Stryker, Medtronic. L. Rangel-Castilla: None. A. Cheema: None. J. Davies: 1; C; National Center for Advancing Translational Sciences of the National Institutes of Health under award number KL2TR001413 to the University of Buffalo. 2; C; Medtronic, Neurotrauma Science, LLC. 4; C; RIST Neurovascular. K. de Macedo Rodrigues: None. J. Grossberg: None. B. Howard: None. C. Kellner: 1; C; Penumbra, Siemens Corp. G. Lanzino: None. S. Tateshima: 2; C; Cerenovus, Medtronic, Neurovasc, Stryker. 4; C; Neurovasc.

Introduction/Purpose Computed tomography perfusion (CTP) is a common imaging modality utilized to assess acute ischemic stroke (AIS) patient eligibility for mechanical thrombectomy. This assessment is done using an ischemic tissue ratio (penumbra to infarct) which is required to be greater than 1 for patients to be eligible for thrombectomy. Since various CTP software utilize different perfusion parameters and thresholds, there are known to be discrepancies in the amount of ischemic tissue quantified for each and therefore conflicting decisions regarding thrombectomy eligibility across software. This study aimed to assess the volumetric agreement of infarct between CTP and 24-hour follow-up fluid-attenuation inversion recovery (FLAIR) magnetic resonance imaging (MRI) along with the number of patients who would be misdiagnosed as ineligible for thrombectomy based on penumbra to infarct ratios by each CTP software. Materials and Methods Eighty-one emergent large vessel occlusion AIS patients who underwent successful reperfusion (thrombolysis in cerebral infarction 2b/2c/3) were included in this study. Predicted infarct and penumbra volumes were quantified within RAPID, Sphere, and Vitrea CTP software and compared with infarct measurements from FLAIR MRI. The following CTP parameters and thresholds were used to quantify ischemic tissue through comparison with contralateral hemispheres: RAPID: infarct=30% reduction of cerebral blood flow (CBF), penumbra=6 second increase in time to reach maximal residue function; Sphere: infarct=25% reduction of CBF (and 5 second increase of time-to-peak (TTP)), penumbra=5 second increase in TTP; Vitrea: infarct=38% reduction in cerebral blood volume (and 5.3 second increase in TTP or 55% reduction in mean-transit-time), penumbra=5.3 second increase in TTP or 5.8 second increase in delay time or 58% reduction in CBF. Penumbra to infarct ratios were calculated utilizing each software. Results Mean infarct differences, represented as 95% confidence intervals, between each software and FLAIR MRI are as follows: RAPID=6.96±4.93 mL, Sphere=-0.07±6.11 mL, Vitrea=4.13±4.73 mL. Mean absolute errors for each CTP software compared with FLAIR MRI are: RAPID=14.48 mL, Sphere=15.43 mL, Vitrea=11.44 mL. Mean penumbra to infarct ratios for each CTP software are: RAPID=70.93; Sphere=32.72; Vitrea=12.33. Total number of patients misdiagnosed as ineligible for thrombectomy (penumbra to infarct ratio less than 1 but successful reperfusion was conducted) for each software: RAPID=1.23% (1/81), Sphere=6.17% (5/81), Vitrea=25.93% (21/81). Conclusions Sphere provided the most accurate results regarding the closest predicted CTP infarct volume to the true FLAIR MRI infarct volume, although with slightly higher error in its measurements compared to RAPID and Vitrea. Penumbra to infarct ratio analysis indicated RAPID and Sphere to provide the most accurate assessment regarding patient eligibility for thrombectomy. However, it appears sacrificing ischemic tissue measurement precision is required for more accurate inclusion of patients as thrombectomy eligible. This is seen by the significantly high mean penumbra to infarct ratio for RAPID which may suggest a caution overestimation of penumbra to label as many patients as possible as thrombectomy eligible for the purpose of regaining lost neurological function. Disclosures R. Rava: None. M. Mokin: 1; C; NIH grant support R21NS109575. 2; C; Canon Medical Systems Corporation, Cerebrotech, Imperative care. M. Waqas: None. J. Davies: 1; C; National Center for Advancing Translational Sciences of the National Institutes of Health under award number KL2TR001413. 3; C; Penumbra. 4; C; RIST Neurovascular. E. Levy: 2; C; Claret Medical, GLG Consulting, Guidepoint Global, Imperative Care, Medtronic, Rebound, StimMed. 4; C; NeXtGen Biologics, RAPID Medical, Claret Medical, Cognition Medical, Imperative Care (formerly the Stroke Project), Rebound Therapeutics, StimMed, Three Rivers Medical. Y. Hoi: 5; C; Canon Medical Systems Inc. A. Siddiqui: 2; C; Amnis Therapeutics, Boston Scientific, Canon Medical Systems USA Inc, Cerebrotech Medical Systems Inc, Cerenovus, Corindus Inc, Endostream Medical Ltd, Guidepoint Global Consulting, Imperative Care, Integra LifeSciences Corp, Medtronic, MicroVention, Northwest University–DSMB Chair for HEAT Trial, Penumbra, Q’Apel Medical Inc, Rapid Medical, Rebound Therapeutics Corp, Serenity Medical Inc, Silk Road Medical, StimMed, Stryker, Three Rivers Medical, Inc., VasSol, W.L. Gore & Associates. 4; C; Amnis Therapeutics, Apama Medical, Blink TBI Inc, Buffalo Technology Partners Inc, Cardinal Consultants, Cerebrotech Medical Systems, Inc, Cognition Medical, Endostream Medical Ltd, Imperative Care, International Medical Distribution Partners, Neurovascular Diagnostics Inc, Q’Apel Medical Inc, Rebound Therapeutics Corp, Rist Neurovascular Inc, Serenity Medical Inc, Silk Road Medical, StimMed, Synchron, Three Rivers Medical Inc, Viseon Spine Inc. C. Ionita: 1; C; Equipment grant from Canon Medical Systems, Cummings Foundation support. K. Snyder: 2; C; Canon Medical Systems Corporation, Penumbra Inc, Medtronic, Jacobs Institute.

Introduction/Purpose Utilization of computed tomography perfusion (CTP) to quantify infarct core and penumbra is commonly conducted to determine acute ischemic stroke patient (AIS) eligibility for endovascular intervention procedures. Accurate estimations of infarct and penumbra spatial location are essential as they provide information regarding the location of the vessel occlusion and regions where infarct will advance to. Discrepancies have been known to occur between various CTP software regarding volumetric calculations and spatial location of ischemic tissue due to different perfusion parameters and thresholds being used across software. This study aimed to assess the spatial and volumetric accuracy of RAPID, Sphere, and Vitrea CTP software predicted infarct and penumbra in comparison with final infarct from fluid-attenuation inversion recovery (FLAIR) magnetic resonance imaging (MRI). Materials and Methods Sixty emergent large vessel occlusion AIS patients treated at a single comprehensive stroke center were included in this study. All patients were required to have undergone initial CTP imaging and 24-hour follow-up FLAIR MRI. Thirty endovascular intervention and 30 medical management patients were included to assess infarct and penumbra tissue, respectively. Endovascular intervention patients were required to have achieved complete successful reperfusion defined as thrombolysis in cerebral infarction 2c/3 to assure all penumbra was salvaged. For medical management patients, it is assumed that all estimated penumbra has converted to infarct on follow-up FLAIR MRI. Within RAPID, Sphere, and Vitrea CTP software, infarct and penumbra tissue was quantified and segmented. Volumetric assessment of CTP infarct and penumbra volumes were conducted using mean infarct differences and mean absolute error (MAE). Spatial accuracy of segmented ischemic tissue was assessed using Dice coefficients, overlap coefficients, sensitivity, specificity, and accuracy metrics. Results Mean infarct differences, represented as 95% confidence intervals, between FLAIR MRI and each CTP software for each patient cohort are: Intervention patients- RAPID=4.9±6.4 mL, Sphere=-4.5±6.6 mL, Vitrea=3.5±4.9 mL; Medical management patients- RAPID=-40.0±23.3 mL, Sphere=-21.4±17.4 mL, Vitrea=7.4±10.3 mL. MAEs for predicted infarct from each software compared to FLAIR MRI infarct are: Intervention patients- RAPID=13.7 mL, Sphere=12.8 mL, Vitrea=7.3 mL; Medical management patients: RAPID=52.5 mL, Sphere=34.3 mL, Vitrea=18.9 mL. Spatial assessment metrics for ischemic tissue for each patient group and for each software are indicated in table 1. Conclusions Volumetric results indicate RAPID, Sphere, and Vitrea CTP software all perform similarly in assessing volumetric agreement with final FLAIR MRI infarct for endovascular intervention patients. However, spatial agreement metrics indicate Vitrea performs the best in locating infarct for endovascular intervention patients. For medical management patients, Vitrea software appears the most accurate in assessing penumbra based on volumetric measurements in addition to overlap coefficients. Disclosures R. Rava: None. M. Mokin: 1; C; NIH grant R21NS109575. 2; C; Canon Medical Systems Corporation, Cerebrotech, Imperative Care. M. Waqas: None. J. Davies: 1; C; National Center for Advancing Translational Sciences of the National Institutes of Health under award number KL2TR001413. 3; C; Penumbra. 4; C; RIST Neurovascular. A. Siddiqui: 2; C; Amnis Therapeutics, Boston Scientific, Canon Medical Systems USA Inc, Cerebrotech Medical Systems Inc, Cerenovus, Corindus Inc, Endostream Medical Ltd., Guidepoint Global Consulting, Imperative Care, Integra LifeSciences Corp, Medtronic, MicroVention, Northwest University–DSMB Chair for HEAT Trial, Penumbra, Q’Apel Medical Inc, Rapid Medical, Rebound Therapeutics Corp, Serenity Medical Inc, Silk Road Medical, StimMed, Stryker, Three Rivers Medical, Inc, VasSol, W.L. Gore & Associates. 4; C; Amnis Therapeutics, Apama Medical, Blink TBI Inc., Buffalo Technology Partner Inc., Cardinal Consultants, Cerebrochtech Medical Systems Inc., Cognition Medical, Endostream Medical Ltd, Imperative Care, International Medical Distribution Partners, Neurovascular Diagnostics Inc., Q’Apel Medical Inc, Rebound Therapeutics Corp, Rist Neurovascular Inc, Serenity Medical Inc, Silk Road Medical, StimMed, Synchron, Three Rivers Medical Inc., Viseon Spine Inc. E. Levy: 2; C; Claret Medical, GLG Consulting, Guidepoint Global, Imperative Care, Medtronic, Rebound, StimMed. 4; C; NeXtGen Biologics, RAPID Medical, Claret Medical, Cognition Medical, Imperative Care (formerly the Stroke Project), Rebound Therapeutics, StimMed, Three Rivers Medical. Y. Hoi: 5; C; Canon Medical Systems Inc. C. Ionita: 1; C; Equipment grant from Canon Medical Systems, Cummings Foundation support. K. Snyder: 2; C; Canon Medical Systems Corporation, Penumbra Inc, Medtronic, Jacobs Institute.

Background Transradial access for neurointerventions offers advantages of fewer access-site complications, reduced procedure time, and greater patient comfort over transfemoral access. Data about transradial access for flow diversion are limited. We share our early experience with transradial access for flow diversion in a relatively large case series. Methods Consecutive patients who underwent Pipeline embolization device (Medtronic) deployment via transradial access were included in the study, irrespective of location and laterality of the intracranial aneurysm. The cases were performed between July 2016 and October 2019. Demographics, aneurysm characteristics, and procedure-related details (including catheter systems used) were recorded and statistically evaluated. Results Thirty-five transradial flow diversion procedures were attempted in 32 patients, of which 33 procedures were successful. In two cases involving left common carotid artery and internal carotid artery access, guide catheter herniation into the aortic arch led to abandonment of transradial access in favor of transfemoral access. The most common aneurysm locations in the transradial access procedures were the posterior communicating artery ( n = 7), ophthalmic artery ( n = 7), and superior hypophyseal artery ( n = 7). Most transradial access procedures (66.7%) were performed using a biaxial catheter system. 6-French Benchmark (Penumbra) and Phenom 27 (Medtronic) were the most commonly utilized guide- and microcatheters, respectively. One patient had intraprocedural subarachnoid hemorrhage. No access-site complications occurred. Conclusion This study demonstrates safety and feasibility of transradial access for Pipeline embolization device deployment and shows the versatility of this approach for different catheter systems. Tortuosity and acute angulation of the left common carotid artery and internal carotid artery were associated with approach failure.

Background: Cerebral venous sinus thrombosis (CVST) is a rare and often misdiagnosed condition with mortality rates ranging from 6 to 10%. Diagnosis and monitoring are typically achieved through noninvasive imaging, including computed tomography or magnetic resonance venography. The current standard of treatment is systemic anticoagulation. However, in patients who continue to decline neurologically or do not show sufficient response to or have absolute contraindications to systemic anticoagulation, endovascular treatments are an alternative. Endovascular options are poorly studied and specific devices have not been developed, partially due to the rare nature of the disease. Here, we present a case report detailing the treatment of extensive CVST from the vein of Galen to the sigmoid sinus using mechanical thrombectomy and local infusions of unfractionated heparin (UFH) and tissue plasminogen activator. Case Description: A 53-year-old man presented and was found to have extensive CVST extending from the vein of Galen to the left sigmoid sinus. Systemic UFH was begun; however, his condition continued to decline, and he was taken for endovascular intervention, wherein mechanical thrombectomy was undertaken using combinations of stent retrievers and balloon catheters, which provided acceptable revascularization. Unfortunately, his hospital course was further complicated by a cerebellar hematoma that was surgically evacuated and reocclusion of the sinus for which a microcatheter was placed for infusion of UFH and tissue plasminogen activator. Conclusion: Complicated CVST may require aggressive endovascular management. Local infusions of heparin and thrombolytic agents as well as mechanical thrombectomy are safe alternative options.

Background Three-dimensional (3D) printing has revolutionized training, education, and device testing. Understanding the design and physical properties of 3D-printed models is important. Objective To systematically review the design, physical properties, accuracy, and experimental outcomes of 3D-printed vascular models used in neurointervention. Methods We conducted a systematic review of the literature between January 1, 2000 and September 30, 2018. Public/Publisher MEDLINE (PubMed), Web of Science, Compendex, Cochrane, and Inspec databases were searched using Medical Subject Heading terms for design and physical attributes of 3D-printed models for neurointervention. Information on design and physical properties like compliance, lubricity, flow system, accuracy, and outcome measures were collected. Results A total of 23 articles were included. Nine studies described 3D-printed models for stroke intervention. Tango Plus (Stratasys) was the most common material used to develop these models. Four studies described a population-representative geometry model. All other studies reported patient-specific vascular geometry. Eight studies reported complete reconstruction of the circle of Willis, anterior, and posterior circulation. Four studies reported a model with extracranial vasculature. One prototype study reported compliance and lubricity. Reported circulation systems included manual flushing, programmable pistons, peristaltic, and pulsatile pumps. Outcomes included thrombolysis in cerebral infarction, post-thrombectomy flow restoration, surgical performance, and qualitative feedback. Conclusion Variations exist in the material, design, and extent of reconstruction of vasculature of 3D-printed models. There is a need for objective characterization of 3D-printed vascular models. We propose the development of population representative 3D-printed models for skill improvement or device testing.

BACKGROUND: Instantaneous wave-free ratios (iFRs) are functional measures of arterial stenosis that have become essential to interventional cardiology procedures. Their use for intracranial submaximal angioplasty (angioplasty with an undersized balloon) has not been studied extensively. OBJECTIVE: To describe the feasibility and technique of iFR measurement for stenosis assessment during intracranial angioplasty. METHODS: We present a series of consecutive patients treated between January 1, 2017 and June 30, 2018 with submaximal intracranial angioplasty in whom pre- and postprocedure iFR measurements were obtained with a Verrata-Volcano pressure wire (Philips, Amsterdam, The Netherlands). We collected patient data on age, sex, comorbid conditions, presenting complaints, modified Rankin scale (mRS) score at admission, neurological findings, procedure duration, fluoroscopy time, intraprocedural complications, length of hospital stay, and mRS score at last clinical follow-up (favorable outcome, 0-2). Angiographic stenosis severity and iFR values were recorded before and after angioplasty. RESULTS: A total of 12 patients underwent iFR-guided angioplasty during the study period. The median patient age was 69.5 yr (range 48-81 yr). All patients had symptomatic intracranial arterial stenosis (3-basilar, 2-vertebral, 6-middle cerebral, 1-internal carotid). Preangioplasty stenosis ranged from 55% to 90%. The median postangioplasty reduction in stenosis was 17% (range 9%-30%). Preangioplasty values ranged from 0.30 to 0.40 (n = 4). Postangioplasty values ranged from 0.6 to 0.9 (n = 5). iFR values improved considerably in all patients. No procedure-related complications occurred. The median follow-up was 8.9 mo (range 3-25 mo). Follow-up outcomes were favorable in 10 patients. CONCLUSION: iFR measurement before and after intracranial angioplasty is feasible. It may be used to assess the adequacy of intracranial angioplasty.

Angiographic Parametric Imaging (API) is a tool based on the parametrization of Time-Density Curves (TDCs) from Digital Subtraction Angiography (DSA). Parameters derived from the TDCs correlate moderately with hemodynamics, yet underuse the hemodynamic information encoded in a TDC. To determine whether better diagnoses can be made through a more complete utilization of the information in the TDCs, we implemented an analysis using Recurrent Neural Networks (RNNs). These are a class of neural networks that analyze and make predictions using time sequences such as the TDCs. We investigated the feasibility of using RNNs to make treatment outcome predictions using TDCs obtained from angiograms of Intracranial Aneurysms (IAs) treated with Pipeline Embolization Devices (PED). Six-month follow-up angiograms were collected to create binary labels regarding treatment outcome (occluded/un-occluded). API parameters obtained were Mean Transit Time, Time to Peak, Time to Arrival, and Peak Height. Parameters were used to simulate TDCs which were normalized to account for variability between interventions. An RNN was trained and tested to predict IA treatment outcome. A 20-fold Monte Carlo Cross Validation was conducted to evaluate robustness of the RNN. The RNN predicted occlusion outcome of IAs with an average accuracy of 74.4% (95% CI, 72.6%-76.1%) and 65.6% (63.4%- 67.2%) and average area under the receiver operating characteristic curve of 0.73 (0.70-0.76) and 0.56 (0.51-0.61) for normalized and un-normalized sub-groups respectively. This study proves the feasibility of using RNNs to predict treatment outcome of IAs treated with a PED using TDCs simulated from temporal features obtained through API.

Purpose: 3D printed Patient-Specific Neurovascular Phantoms (3DP-PSNP) containing significant portions of the neurovasculature can be used to develop and test new diagnostic tools. The purpose of this research is to assess the use of 3DP-PSNP to study the correlation between Angiographic Parametric Imaging (API) features and the severity of carotid artery disease. Materials and Methods: We developed 3DP-PSNP for twenty patients with carotid atherosclerosis and performed two studies. In the first study, we used three phantoms with complete Circle of Willis (COW) with none, moderate and severe stenosis respectively. In the second experiment, all phantoms regardless of the COW structure were used. 3DP-PSNPs were connected in a simulated physiological pulsatile flow loop and Digital Subtractive Angiography (DSA) was performed by injecting 10 ml of contrast at 10 mL/s. An API software calculated imaging biomarkers: time-to-peak TTP, mean transit time MTT, time to arrival TTA, peak height PH, and area under the curve AUC for both carotids. Results: For none, moderate, and severe stenosis respectively, absolute mean percent differences between diseased vs. contralateral carotids were: 1.9%, 8.1%, 32.3% TTP; 6.8%, 7.5%, 41.0% TTA; 13.2%, 12.4%, 6.4% MTT; 8.7%, 11.3%, 97.6% PH; and 10.3%, 22.6%, 100% AUC. Injection parameters did not cause significant change to the difference between diseased and contralateral carotids. The second experiment showed strong correlation between the TTA and location of the stenosis, regardless of COW configuration. Conclusions: Overall, API was assessed in 3DP-PSNPs and shown to have increasing differences between diseased and contralateral carotid arteries with increasing severity.

Convolutional neural networks (CNN) can automate the quantitative assessment of intracranial aneurysms (IAs); however, as a “black-box” technique, it does not allow users to understand which image features are most important, and thus how to improve network predictions. Class-activation maps (CAMs) are used to visualize which image regions trigger a trained CNN, thus lending insight into how a CNN makes a decision. This work investigated the use of CAMs to identify differences in network activation inside IAs for an image segmentation task for the goal of optimizing the pre-processing framework. Three hundred and fifty angiographic images of pre- and post-coiled IAs were retrospectively collected. The IAs were manually contoured, angiographic sequences were flattened along the time-axis using different techniques (average, median, standard deviation, or minimum value), and flattened sequences and masks were put to a CNN tasked with IA segmentation. CAMs were output to visualize the most salient aneurysmal features. Network activation was higher in the IA peripheral region compared with the IA middle region indicating the IA periphery is more predictive for segmentation. Flattening angiographic sequences using the average value along the time-axis leads to the most accurate IA segmentations with an average Dice coefficient of 0.765 and an average Jaccard Index of 0.624 over the test cohort. This work indicates that CAMs can aid in understanding of a CNN’s segmentation decisions. Fine-tuning and automation of algorithms along with network-input image preprocessing based on these results may improve IA predictive models.

Purpose: Intracranial arteriovenous malformations (AVMs) are severe neurovascular diseases in which the arterial branches of an area of the brain communicate directly with venous circulation through a network of dilated vasculature (nidus) which significantly increases the risk of hemorrhage. Treatment plans typically incorporate direct embolization with liquid materials delivered via micro-catheters under fluoroscopy. Currently, the progression and success of this procedure are qualitatively evaluated using digitally subtracted angiographic (DSA) sequences. This study sought to validate the use of Angiographic Parametric Imaging (API) for quantitative analysis of the hemodynamic changes caused by embolization treatment using imaging biomarkers. Materials and Methods: 36 patients with AVMs were selected randomly from a list of patients with known symptoms at presentation. For each, at least one set of frontal and lateral angiograms were analyzed using API. Parametric maps were calculated for five imaging biomarkers, including time to peak (TTP), mean transit time (MTT), time to arrival (TTA), peak height (PH), and area under the curve (AUC). Regions of interest (ROIs) were selected over the feeding arteries, AVM nidus, and draining veins. Average ROI parameters were calculated and changes in flow due to embolization were quantified through a percent change analysis. Results were verified using correlation coefficients across AVM vasculature at multiple sites following normalization. Results: Frontal to lateral correlation coefficients; TTP, 0.54±0.07; MTT, 0.24±0.09; TTA 0.60±0.06; PH, 0.33±0.08; AUC, 0.22±0.09. Nidus to principle draining vein (PDV) correlation coefficients; TTP, 0.75±0.03; MTT, 0.64±0.04; TTA, 0.80±0.02; PH, 0.32±0.06; AUC, 0.68±0.04. PH and AUC values affected by DSA inversion. Conclusions: The study concludes that the API software is reliable in determining the flow parameters throughout the AVM, provided that the selected ROI is consistent between frontal and lateral scans and DSA selection is optimal.

BACKGROUND AND PURPOSE: Brain CTP is used to estimate infarct and penumbra volumes to determine endovascular treatment eligibility for patients with acute ischemic stroke. We aimed to assess the accuracy of a Bayesian CTP algorithm in determining penumbra and final infarct volumes. MATERIALS AND METHODS: Data were retrospectively collected for 105 patients with acute ischemic stroke (55 patients with successful recanalization [TICI 2b/2c/3] and large-vessel occlusions and 50 patients without interventions). Final infarct volumes were calculated using DWI and FLAIR 24 hours following CTP imaging. RAPID and the Vitrea Bayesian CTP algorithm (with 3 different settings) predicted infarct and penumbra volumes for comparison with final infarct volumes to assess software performance. Vitrea settings used different combinations of perfusion maps (MTT, TTP, CBV, CBF, delay time) for infarct and penumbra quantification. Patients with and without interventions were included for assessment of predicted infarct and penumbra volumes, respectively. RESULTS: RAPID and Vitrea default setting had the most accurate final infarct volume prediction in patients with interventions ([Spearman correlation coefficient, mean infarct difference] default versus FLAIR: [0.77, 4.1 mL], default versus DWI: [0.72, 4.7 mL], RAPID versus FLAIR: [0.75, 7.5 mL], RAPID versus DWI: [0.75, 6.9 mL]). Default Vitrea and RAPID were the most and least accurate in determining final infarct volume for patients without an intervention, respectively (default versus FLAIR: [0.76, –0.4 mL], default versus DWI: [0.71, –2.6 mL], RAPID versus FLAIR: [0.68, −49.3 mL], RAPID versus DWI: [0.65, –51.5 mL]). CONCLUSIONS: Compared with RAPID, the Vitrea default setting was noninferior for patients with interventions and superior in penumbra estimation for patients without interventions as indicated by mean infarct differences and correlations with final infarct volumes.

BACKGROUND AND PURPOSE: Quality of visualization of treatment devices during critical stages of endovascular interventions, can directly impact their safety and efficacy. Our aim was to compare the visualization of neurointerventional procedures and treatment devices using a 194-μm pixel flat panel detector mode and a 76-μm pixel complementary metal oxide semiconductor detector mode (high definition) of a new-generation x-ray detector system using a blinded-rater study. MATERIALS AND METHODS: Deployment of flow-diversion devices for the treatment of internal carotid artery aneurysms was performed under flat panel detector and high-definition-mode image guidance in a neurointerventional phantom simulating patient cranium and tissue attenuation, embedded with 3D-printed intracranial vascular models, each with an aneurysm in the ICA segment. Image-sequence pairs of device deployments for each detector mode, under similar exposure and FOV conditions, were evaluated by 2 blinded experienced neurointerventionalists who independently selected their preferred image on the basis of visualization of anatomic features, image noise, and treatment device. They rated their selection as either similar, better, much better, or substantially better than the other choice. Inter- and intrarater agreement was calculated and categorized as poor, moderate, and good. RESULTS: Both raters demonstrating good inter- and intrarater agreement selected high-definition-mode images with a frequency of at least 95% each and, on average, rated the high-definition images as much better than flat panel detector images with a frequency of 73% from a total of 60 image pairs. CONCLUSIONS: Due to their higher resolution, high-definition-mode images are sharper and visually preferred compared with the flat panel detector images. The improved imaging provided by the high-definition mode can potentially provide an advantage during neurointerventional procedures.

Objective Precise morphologic evaluation is important for intracranial aneurysm (IA) management. At present, clinicians manually measure the IA size and neck diameter on 2-dimensional (2D) digital subtraction angiographic (DSA) images and categorize the IA shape as regular or irregular on 3-dimensional (3D)-DSA images, which could result in inconsistency and bias. We investigated whether a computer-assisted 3D analytical approach could improve IA morphology assessment. Methods Five neurointerventionists evaluated the size, neck diameter, and shape of 39 IAs using current and computer-assisted 3D approaches. In the computer-assisted 3D approach, the size, neck diameter, and undulation index (UI, a shape irregularity metric) were extracted using semiautomated reconstruction of aneurysm geometry using 3D-DSA, followed by IA neck identification and computerized geometry assessment. Results The size and neck diameter measured using the manual 2D approach were smaller than computer-assisted 3D measurements by 2.01 mm (P Conclusions Computer-assisted 3D morphology analysis can improve accuracy and consistency in measurements compared with manual 2D measurements. It can also more reliably quantify shape irregularity using the UI. Future application of computer-assisted analysis tools could help clinicians standardize morphology evaluations, leading to more consistent IA evaluations.

Background Current outcomes prediction tools are largely based on and limited by regression methods. Utilization of machine learning (ML) methods that can handle multiple diverse inputs could strengthen predictive abilities and improve patient outcomes. Inpatient length of stay (LOS) is one such outcome that serves as a surrogate for patient disease severity and resource utilization. Objective To develop a novel method to systematically rank, select, and combine ML algorithms to build a model that predicts LOS following craniotomy for brain tumor. Methods A training dataset of 41 222 patients who underwent craniotomy for brain tumor was created from the National Inpatient Sample. Twenty-nine ML algorithms were trained on 26 preoperative variables to predict LOS. Trained algorithms were ranked by calculating the root mean square logarithmic error (RMSLE) and top performing algorithms combined to form an ensemble. The ensemble was externally validated using a dataset of 4592 patients from the National Surgical Quality Improvement Program. Additional analyses identified variables that most strongly influence the ensemble model predictions. Results The ensemble model predicted LOS with RMSLE of .555 (95% confidence interval, .553-.557) on internal validation and .631 on external validation. Nonelective surgery, preoperative pneumonia, sodium abnormality, or weight loss, and non-White race were the strongest predictors of increased LOS. Conclusion An ML ensemble model predicts LOS with good performance on internal and external validation, and yields clinical insights that may potentially improve patient outcomes. This systematic ML method can be applied to a broad range of clinical problems to improve patient care.

A direct aspiration-first pass technique (ADAPT) has recently gained popularity for the treatment of large vessel ischemic stroke. Here, we sought to create a machine learning-based model that uses pre-treatment imaging metrics to predict successful outcomes for ADAPT in middle cerebral artery (MCA) stroke cases. In 119 MCA strokes treated by ADAPT, we calculated four imaging parameters—clot length, perviousness, distance from the internal carotid artery (ICA) and angle of interaction (AOI) between clot/catheter. We determined treatment success by first pass effect (FPE), and performed univariate analyses. We further built and validated multivariate machine learning models in a random train-test split (75%:25%) of our data. To test model stability, we repeated the machine learning procedure over 100 randomizations, and reported the average performances. Our results show that perviousness (p = 0.002) and AOI (p = 0.031) were significantly higher and clot length (p = 0.007) was significantly lower in ADAPT cases with FPE. A logistic regression model achieved the highest accuracy (74.2%) in the testing cohort, with an AUC = 0.769. The models had similar performance over the 100 train-test randomizations (average testing AUC = 0.768 ± 0.026). This study provides feasibility of multivariate imaging-based predictors for stroke treatment outcome. Such models may help operators select the most adequate thrombectomy approach.

The literature demonstrates a favorable first pass effect with balloon-guide catheter (BGC) for mechanical thrombectomy. An 8F BGC is routinely used with femoral access. We present the first video report of 8F BGC advanced through the radial artery using a sheathless technique (video 1). An approximately 70-year-old patient presented with left-sided hemiplegia, neglect, and dysarthria. A CT angiogram demonstrated right M1 occlusion, and the patient underwent urgent mechanical thrombectomy. Radial approach was preferred owing to patient history of anticoagulation. A 6F Sim Select intermediate catheter was used to minimize the step off as the 8F BGC was advanced into the radial artery over an 035 exchange-length Advantage Glidewire. A skin nick over the Glidewire Advantage facilitated the introduction of the 8F BGC into the radial artery. Standard mechanical thrombectomy using a combination of stent retriever and aspiration catheter (Solumbra technique) was performed, and thrombolysis in cerebral infarction 3 recanalization was achieved after a single pass. The National Institutes of Health Scale score improved from 12 to 4, with mild left facial droop, dysarthria, and decreased speech fluency. The patient was discharged from the hospital on postoperative day 2. Ultrasound should be used for immediate assessment of radial artery size and conversion to femoral access without delay if the radial artery is less than 2.5 mm.Video 1

Introduction Although mechanical thrombectomy (MT) is a proven therapy for acute large vessel occlusion strokes, futile recanalization in the elderly is common and costly. Strategies to minimize futile recanalization may reduce unnecessary thrombectomy transfers and procedures. We evaluated whether a simple and rapid visual assessment of brain atrophy and leukoaraiosis on a plain head CT correlates with futile stroke recanalization in the elderly. Methods Consecutive stroke patients admitted for thrombectomy, older than 65 years of age, all with TICI 2b/3 recanalization rates were retrospectively studied from multiple comprehensive stroke centers. Brain atrophy and leukoaraiosis were visually analyzed from pre-intervention plain head CTs using a simplified scheme based on validated scales. Baseline demographics were collected and the primary outcome measure was 90-day modified Rankin score (mRS). Cochran-Armitage trend test was applied in analyzing the association of the severity of brain atrophy and leukoaraiosis with 90-day mRS. Results Between 2017 and 2019, 175 patients > 65 years who underwent thrombectomy with TICI 2b/3 recanalization from two comprehensive stroke centers were evaluated. The median age was 77 years. IV-tPA was given in 59% of patients, average initial NIHSS was 19, average baseline mRS was 0.77 and median time to recanalization was 300 minutes. Age and severity of atrophy/leukoaraiosis was categorized into three groups of increasing severity and associated with 90 day mRS 0-3 rates of 62%, 49% and 41% (p=0.037) respectively. Conclusions A simplified, visual assessment of the degree of brain atrophy and leukoaraiosis measured on plain head CT correlates with futile recanalization in patients age >65 years. Although additional validation is needed, these findings suggest that brain atrophy and leukoaraiosis may have value as a surrogate marker of prestroke functional status. In doing so, simplified visual plain head CT grading scales may minimize elderly futile recanalization.

OBJECTIVE Acute basilar artery occlusion (BAO) is a rare large-vessel occlusion associated with high morbidity and mortality. Modern thrombectomy with stent retrievers and large-bore aspiration catheters is highly effective in achieving recanalization, but a direct comparison of different techniques for acute BAO has not been performed. Therefore, the authors sought to compare the technical effectiveness and clinical outcomes of stent retriever–assisted aspiration (SRA), aspiration alone (AA), and a stent retriever with or without manual aspiration (SR) for treatment of patients presenting with acute BAO and to evaluate predictors of clinical outcome in their cohort. METHODS A retrospective analysis of databases of large-vessel occlusion treated with endovascular intervention at two US endovascular neurosurgery centers was conducted. Patients ≥ 18 years of age with acute BAO treated between January 2013 and December 2020 with stent retrievers or large-bore aspiration catheters were included in the study. Demographic information, procedural details, angiographic results, and clinical outcomes were extracted for analysis. RESULTS Eighty-three patients (median age 67 years [IQR 58–76 years]) were included in the study; 33 patients (39.8%) were female. The median admission National Institutes of Health Stroke Scale (NIHSS) score was 16 (IQR 10–21). Intravenous alteplase was administered to 26 patients (31.3%). The median time from symptom onset to groin or wrist puncture was 256 minutes (IQR 157.5–363.0 minutes). Overall, successful recanalization was achieved in 74 patients (89.2%). The SRA technique had a significantly higher rate of modified first-pass effect (mFPE; 55% vs 31.8%, p = 0.032) but not true first-pass effect (FPE; 45% vs 34.9%, p = 0.346) than non-SRA techniques. Good outcome (modified Rankin Scale [mRS] score 0–2) was not significantly different among the three techniques. Poor outcome (mRS score 3–6) was associated with a higher median admission NIHSS score (12.5 vs 19, p = 0.007), a higher rate of adjunctive therapy usage (9% vs 0%, p < 0.001), and a higher rate of intraprocedural complications (10.7% vs 14.5%, p = 0.006). The admission NIHSS score significantly predicted good outcome (OR 0.98, 95% CI 0.97–0.099; p = 0.032). Incomplete recanalization after thrombectomy significantly predicted mortality (OR 1.68, 95% CI 1.18–2.39; p = 0.005). CONCLUSIONS The evaluated techniques resulted in high recanalization rates. The SRA technique was associated with a higher rate of mFPE than AA and SR, but the clinical outcomes were similar. A lower admission NIHSS score predicted a better prognosis for patients, whereas incomplete recanalization after thrombectomy predicted mortality.

Background The management of intracranial aneurysm (IA) is challenging. Clinicians often rely on varied and intuitively disparate ways of evaluating rupture risk that may only partially take into account complex hemodynamic and morphologic factors. We developed a prototype of a clinically oriented, streamlined, computational platform, AView, for rapid assessment of hemodynamics and morphometrics in clinical settings. To show the potential clinical utility of AView, we report our initial multicenter experience highlighting the possible advantages of morphologic and hemodynamic analysis of IAs. Methods AView software was deployed across 8 medical centers (6 in the United States, 2 in Japan). Eight clinicians were trained and used the AView software between September 2012 and January 2013. Results We present 12 illustrative cases that show the potential clinical utility of AView. For all, morphology and hemodynamics, flow visualization, and rupture resemblance score (a surrogate for rupture risk) were provided. In 3 cases, AView could confirm the clinicians' decision to treat; in 3 cases, it could suggest which aneurysms may be at greater risk among multiple aneurysms; in 5 cases, AView could provide additional information for use during treatment decisions for ambiguous situations. In one stent-assisted coiling case, flow visualization predicted that the intuitive choice for stent placement could have resulted in sacrifice of an anterior cerebral artery due to blockage by coils and led clinicians to reconsider treatment plans. Conclusions AView has the potential to confirm decisions to treat IAs, suggest which among multiple aneurysms to treat, and guide treatment decisions. Furthermore, the flow visualization it affords can inform aneurysm treatment planning and potentially avoid poor outcomes.

OBJECTIVETreatment of cerebrovascular malformations has grown in complexity with the development of multimodal approaches, including microsurgery, endovascular treatments, and radiosurgery. In spite of this changing standard of care, the provision of care continues across a variety of settings. The authors sought to determine the risk of adverse outcome after treatment of patients with vascular malformations in the US. Patient, surgeon, and hospital characteristics, including volume, were tested as potential outcome predictors.METHODSThe authors examined data collected between 2000 and 2009 in the Nationwide Inpatient Sample (NIS) database, assessing safety, quality, and cost-effectiveness. They performed multivariate analyses of trends in microsurgical, radiosurgical, and endovascular treatment by hospital and surgeon volume, using death, routine discharge percentage, length of stay (LOS), complications, and hospital charges as end points. They further computed the value of care, which was defined as the ratio of the functional outcome (routine discharge percentage) to cost of care to the payer (hospital charges).RESULTSThe authors identified 8227 patients with vascular malformations who were treated at US hospitals. Hospitals and surgeons were classified by yearly case volume. Compared with low-volume hospitals (2 or fewer cases/year), high-volume hospitals (16 or more cases/year) had shorter LOS (3 vs 2 days, p = 0.005), higher total charges ($37,374 vs $19,986, p = 0.003), more frequent discharge to home (p < 0.001), and lower mortality rates (0.7% vs 1.16%, p = 0.010). High-volume surgeons (7 or more cases/year) likewise had superior outcomes compared with low-volume surgeons (1 or fewer cases/year), with shorter LOS (2 vs 3 days, p = 0.03), more frequent discharge to home (p < 0.001), and lower mortality rates (0.7% vs 1.10%, p = 0.005). Underlying these outcomes, the rates of intervention for surgery, angiography, embolization, and radiosurgery were likewise significantly different in high- versus low-volume practices.Based on these results the authors modeled how outcomes might change if care were consolidated at designated centers of excellence (COEs), and found that on an annual basis, care at high-volume hospital COEs would result in 18.5 fewer deaths, 1252.1 fewer hospital days, 182.7 more discharges home without additional services, 48.5 fewer medical complications, and 117.4 fewer perioperative complications. Surgeon-level rates for high-volume COEs demonstrated an even larger benefit over current standards, with 27.4 fewer deaths, 10,713.7 fewer hospital days, a $51.6-million reduction in charges, 370.9 additional routine discharges, and reduced complications in all categories (27.8 fewer surgical, 198.0 fewer medical, and 32.1 fewer perioperative) compared with care at non-COEs.CONCLUSIONSFor patients with vascular malformations who were treated in the US between 2000 and 2009, treatment performed at high-volume centers was associated with significantly lower morbidity and, for high-volume surgeons, with lower mortality rates. These data suggest that treatment by high-volume institutions and surgeons will yield superior outcomes and superior value. The authors therefore advocate the creation of care paradigms that triage patients to high-volume institutions and surgeons, which can serve as cerebrovascular COEs.

BACKGROUND AND PURPOSE: Tandem aneurysms are defined as multiple aneurysms located in close proximity on the same parent vessel. Endovascular treatment of these aneurysms has rarely been reported. Our aim was to evaluate the safety and efficacy of a single Pipeline Embolization Device for the treatment of tandem aneurysms of the internal carotid artery. MATERIALS AND METHODS: A retrospective analysis of consecutive aneurysms treated with the Pipeline Embolization Device between 2009 and 2016 at 3 institutions in the United States was performed. Cases included aneurysms of the ICA treated with a single Pipeline Embolization Device, and they were divided into tandem versus solitary. Angiographic and clinical outcomes were compared. RESULTS: The solitary group (median age, 58 years) underwent 184 Pipeline Embolization Device procedures for 184 aneurysms. The tandem group (median age, 50.5 years) underwent 34 procedures for 78 aneurysms. Aneurysms were primarily located along the paraophthalmic segment of the ICA in both the single and tandem groups (72.3% versus 78.2%, respectively, P = .53). The median maximal diameters in the solitary and tandem groups were 6.2 and 6.7 mm, respectively. Complete occlusion on the last angiographic follow-up was achieved in 75.1% of aneurysms in the single compared with 88.6%% in the tandem group (P = .06). Symptomatic thromboembolic complications were encountered in 2.7% and 8.8% of procedures in the single and tandem groups, respectively (P = .08). CONCLUSIONS: Tandem aneurysms of the ICA can be treated with a single Pipeline Embolization Device with high rates of complete occlusion. While there appeared to be a trend toward higher thromboembolic complication rates, this did not reach statistical significance.

Background Neuroendovascular intervention has become a key treatment option for acute ischemic stroke. The Sofia (6F) PLUS catheter was designed for neurovascular access for diagnostic or therapeutic interventions. Objective To report the first series describing use of the Sofia PLUS intermediate/distal access reperfusion catheter in the treatment of acute ischemic stroke. Methods In this retrospective study, 41 stroke cases were identified in which the catheter was utilized for thrombolysis/thrombectomy. Mean preprocedure National Institutes of Health Stroke Scale score was 16.5 ± 5.2 (range 4-29). Occluded vessels included the M1 segment, M2 segment, internal carotid artery terminus, cervical internal carotid artery, and basilar artery. Results Successful positioning of the Sofia PLUS catheter near the occlusion site was achieved in 38 (92.7%) of 41 cases in which thrombectomy or thrombolysis was attempted using intraarterial tissue plasminogen activator, a direct aspiration first-pass technique, and/or stent retrieval. A postprocedure thrombolysis in cerebral infarction (TICI) score of 2b/3 was achieved in 37 of 41 cases. Of 15 cases where the Sofia PLUS was used for a direct aspiration first-pass technique, TICI 2b/3 was achieved in 11 (73.3%). In one case where intra-arterial tissue plasminogen activator was used as the only treatment modality, TICI 2a was achieved. No device-related or catheter-related complications were observed. The mean 7-d-postprocedure National Institutes of Health Stroke Scale score among the 39 survivors was 8.5 ± 7.3 (range 0-23). Conclusion Initial results with use of the Sofia (6F) PLUS for endovascular treatment of acute ischemic stroke have been encouraging. Experience with a larger series is warranted to further evaluate the safety and efficacy of this device and compare it with other reperfusion catheters.

Background The superficial temporal artery (STA) is underutilized as an interposition graft because current techniques expose and harvest STA above the level of the zygoma. This technique yields a diminutive arterial segment in both length and diameter, which limits its use for extracranial-intracranial bypass. Objective To introduce a safe and efficient technique for harvesting of the infrazygomatic segment of the STA. Methods Scalp layers, STA, and the facial nerve were studied in 18 specimens. The length of the STA segment harvested below the superior border of the zygomatic arch was measured. Safety of this technique was assessed by measuring the distance between the facial nerve and the STA. Results The galea and subgaleal fat pad were the only anatomical planes found between the facial nerve and the STA below the zygomatic arch. A dense subcutaneous band of galea contained the STA and allowed proximal dissection of the artery without exposing the facial nerve. The average length of the artery harvested between the zygomatic arch and the parotid gland was 20 mm. Conclusion Subcutaneous dissection within the galea below the level of the zygomatic arch and preservation of the dense subcutaneous band surrounding the STA avoids transecting the facial nerve branches while providing increased STA exposure. This anatomical knowledge may increase the use of STA as an interposition graft in cerebrovascular bypass procedures and reduce the need to harvest grafts through additional incisions at remote sites.

OBJECTIVE Previous studies have found that ruptured intracranial aneurysms (RIAs) have distinct morphological and hemodynamic characteristics, including higher size ratio and oscillatory shear index and lower wall shear stress. Unruptured intracranial aneurysms (UIAs) that possess similar characteristics to RIAs may be at a higher risk of rupture than those UIAs that do not. The authors previously developed the Rupture Resemblance Score (RRS), a data-driven computer model that can objectively gauge the similarity of UIAs to RIAs in terms of morphology and hemodynamics. The authors aimed to explore the clinical utility of RRS in guiding the management of UIAs, especially for challenging cases such as small UIAs. METHODS Between September 2018 and June 2019, the authors retrospectively collected consecutive challenging cases of incidentally identified UIAs that were discussed during their weekly multidisciplinary neurovascular conference. From patient 3D digital subtraction angiography, they reconstructed the aneurysm geometry and performed computer-assisted 3D morphology analysis and computational fluid dynamics simulation. They calculated RRS for every UIA case and compared it against the treatment decision made at the neurovascular conference as well as the recommendation based on the unruptured intracranial aneurysm treatment score (UIATS). RESULTS Forty-seven patients with 79 UIAs, 90% of which were < 7 mm in size, were included in this study. The mean RRS (range 0.0–1.0) was 0.24 ± 0.31. At the conferences, treatment was endorsed for 45 of the UIAs (57%). These cases had significantly higher RRSs than the 34 cases suggested for observation (0.33 ± 0.34 vs 0.11 ± 0.19, p < 0.001). The UIATS-based recommendations were “observation” for 24 UIAs (30%), “treatment” for 21 UIAs (27%), and “not definitive” for 34 UIAs (43%). These “not definitive” cases were stratified by RRS based on similarity to RIAs. CONCLUSIONS Although not a rupture predictor, RRS is a data-driven model that gauges the similarity of UIAs to RIAs in terms of morphology and hemodynamics. In cases in which the UIATS-based recommendation is not definitive, RRS provides additional stratification to assist the identification of high-risk UIAs. The current study highlights the clinical utility of RRS in a real-world setting as an adjunctive tool for the management of UIAs.

Objective Despite an increasing focus on endovascular treatment of cerebral aneurysms, microsurgical clipping remains an integral part of management. We evaluated the safety and effectiveness of microsurgical clipping performed by dual-trained neurosurgeons at our institute, which has adopted an endovascular first approach. Methods We retrospectively reviewed clinical and radiographic data of 412 aneurysms in 375 patients treated with microsurgical clipping. Univariate and multivariate analyses were performed to identify predictive outcome factors. We defined favorable outcome as a modified Rankin Scale (mRS) score of 0–2 at last clinical follow-up; unfavorable outcome was an mRS score of 3–6. We compared outcomes in our series with those of seminal aneurysm clipping series. Results Clipping of 330 of 351 unruptured aneurysms (94.01%) was associated with favorable outcome during the follow-up period (mean, 26.5 months). On univariate analysis, older patient age, intraoperative rupture, and higher baseline mRS scores were associated with unfavorable outcome in the unruptured cohort. On multivariate analysis, older age, higher baseline mRS scores, and posterior circulation aneurysm location were predictive of unfavorable outcome. Clipping of 46 of 61 ruptured aneurysms (75.4%) was associated with favorable outcome during the follow-up period (mean, 23.1 months). On univariate analysis, left-sided aneurysms, intraoperative rupture, and large aneurysm size were associated with unfavorable outcome in the ruptured cohort. On multivariate analysis, female sex was predictive of unfavorable outcome. Conclusions Our ruptured and unruptured cohort results compared favorably with those in seminal series. Treatment by neurosurgeons adept at both endovascular and microsurgical techniques may improve clinical outcomes.

BACKGROUND AND PURPOSE: In patients with SAH with multiple intracranial aneurysms, often the hemorrhage pattern does not indicate the rupture source. Angiographic findings (intracranial aneurysm size and shape) could help but may not be reliable. Our purpose was to test whether existing parameters could identify the ruptured intracranial aneurysm in patients with multiple intracranial aneurysms and whether composite predictive models could improve the identification. MATERIALS AND METHODS: We retrospectively collected angiographic and medical records of 93 patients with SAH with at least 2 intracranial aneurysms (total of 206 saccular intracranial aneurysms, 93 ruptured), in which the ruptured intracranial aneurysm was confirmed through surgery or definitive hemorrhage patterns. We calculated 13 morphologic and 10 hemodynamic parameters along with location and type (sidewall/bifurcation) and tested their ability to identify rupture in the 93 patients. To build predictive models, we randomly assigned 70 patients to training and 23 to holdout testing cohorts. Using a linear regression model with a customized cost function and 10-fold cross-validation, we trained 2 rupture identification models: RIM(C) using all parameters and RIM(M) excluding hemodynamics. RESULTS: The 25 study parameters had vastly different positive predictive values (31%–87%) for identifying rupture, the highest being size ratio at 87%. RIM(C) incorporated size ratio, undulation index, relative residence time, and type; RIM(M) had only size ratio, undulation index, and type. During cross-validation, positive predictive values for size ratio, RIM(M), and RIM(C) were 86% ± 4%, 90% ± 4%, and 93% ± 4%, respectively. In testing, size ratio and RIM(M) had positive predictive values of 85%, while RIM(C) had 92%. CONCLUSIONS: Size ratio was the best individual factor for identifying the ruptured aneurysm; however, RIM(C), followed by RIM(M), outperformed existing parameters.

BackgroundA new dual resolution imaging x-ray detector system (Canon Medical Systems Corporation, Tochigi, Japan) has a standard resolution 194 µm pixel conventional flat-panel detector (FPD) mode and a high-resolution 76 µm high-definition (Hi-Def) mode in a single unit. The Hi-Def mode enhances the visualization of the intravascular devices.ObjectiveWe report the clinical experience and physician evaluation of this new detector system with Hi-Def mode for the treatment of intracranial aneurysms using a Pipeline embolization device (PED).MethodsDuring intervention at our institute, under large field of view (FOV) regular resolution FPD mode imaging, the catheter systems and devices were first guided to the proximity of the treatment area. Final placement and deployment of the PED was performed under Hi-Def mode guidance. A post-procedure 9-question physician survey was conducted to qualitatively assess the impact of Hi-Def mode visualization on physicians’ intraoperative decision-making. One-sample t-test was performed on the responses from the survey. Dose values reported by the x-ray unit were also recorded.ResultsTwenty-five cases were included in our study. The survey results indicated that, for each of the nine questions, the physicians in all cases indicated that the Hi-Def mode improved visualization compared with the FPD mode. For the 25 cases, the mean cumulative entrance air kerma was 2.35 Gy, the mean dose area product (DAP) was 173.71 Gy.cm2, and the mean x-ray exposure time was 39.30 min.ConclusionsThe Hi-Def mode improves visualization of flow diverters and may help in achieving more accurate placement and deployment of devices.

BackgroundAngiographic parametric imaging (API), based on digital subtraction angiography (DSA), is a quantitative imaging tool that may be used to extract contrast flow parameters related to hemodynamic conditions in abnormal pathologies such as intracranial aneurysms (IAs).ObjectiveTo investigate the feasibility of using deep neural networks (DNNs) and API to predict IA occlusion using pre- and post-intervention DSAs.MethodsWe analyzed DSA images of IAs pre- and post-treatment to extract API parameters in the IA dome and the corresponding main artery (un-normalized data). We implemented a two-step correction to account for injection variability (normalized data) and projection foreshortening (relative data). A DNN was trained to predict a binary IA occlusion outcome: occluded/unoccluded. Network performance was assessed with area under the receiver operating characteristic curve (AUROC) and classification accuracy. To evaluate the effect of the proposed corrections, prediction accuracy analysis was performed after each normalization step.ResultsThe study included 190 IAs. The mean and median duration between treatment and follow-up was 9.8 and 8.0 months, respectively. For the un-normalized, normalized, and relative subgroups, the DNN average prediction accuracies for IA occlusion were 62.5% (95% CI 60.5% to 64.4%), 70.8% (95% CI 68.2% to 73.4%), and 77.9% (95% CI 76.2% to 79.6%). The average AUROCs for the same subgroups were 0.48 (0.44–0.52), 0.67 (0.61–0.73), and 0.77 (0.74–0.80).ConclusionsThe study demonstrated the feasibility of using API and DNNs to predict IA occlusion using only pre- and post-intervention angiographic information.

Purpose: Biomarkers related to hemodynamics can be quantified using angiographic parametric imaging (API), which is a quantitative imaging method that uses digital subtraction angiography (DSA). We aimed to assess the accuracy of API in locating infarct core within large vessel occlusion (LVO) acute ischemic stroke (AIS) patients. Approach: Data were retrospectively collected for 25 LVO AIS patients who achieved successful recanalization. DSA data from lateral and anteroposterior (AP) views were loaded into API software to generate hemodynamic parameter maps. Relative differences in hemispherical regions for each API parameter were calculated. Ground truth infarct core locations were obtained using 24-h follow-up fluid-attenuation inversion recovery (FLAIR) MRI imaging. FLAIR MRI infarct locations were registered with DSA images to determine infarct regions in API parameter maps. Relative differences across hemispheres for each API parameter were plotted against each other. A support vector machine was used to determine the optimal hyperplane for classifying regions as infarct or healthy tissue. Results: For the lateral and AP views, respectively, the most accurate classification of infarct regions came from plotting mean transit time (MTT) versus peak height (PH) [accuracy = 0.8125 ± 0.0012 (95%)], the area under the receiver operator characteristic curve ( AUROC ) = 0.8946 ± 0.0000 (95%), and plotting MTT versus the area under the curve (AUC) [accuracy = 0.7957 ± 0.0011 (95%), AUROC = 0.8759 ± 0.0000 (95%)]. Conclusions: API provides accurate assessment of locating ischemic core in AIS LVO patients and has the potential for clinical benefit by determining infarct core location and growth in real time for intraoperative decision making.

BACKGROUND AND PURPOSE: Visualization of structural details of treatment devices during neurointerventional procedures can be challenging. A new true 2-resolution imaging x-ray detector system (Canon Medical Systems Corporation, Tochigi, Japan) features a 194μm pixel conventional flat-panel detector (FPD) mode and a 76μm pixel high-resolution high-definition (Hi-Def) zoom mode in 1 detector panel. The Hi-Def zoom mode was developed for use in interventional procedures requiring superior image quality over a small field-of-view (FOV). We report successful use of this imaging system during intracranial aneurysm treatment in 1 patient with a Pipeline-embolization device (PED; Medtronic, Dublin, Ireland) and 1 patient with a low-profile visualized intramural support (LVIS Blue) device (MicroVention-Terumo, Somerset, New Jersey) plus adjunctive coiling. METHODS: A guide catheter was advanced from the femoral artery insertion site to the proximity of each lesion using standard FPD mode. Under magnified small FOV Hi-Def imaging mode, an intermediate catheter and microcatheters were guided to the treatment site, and the PED and LVIS Blue plus coils were deployed. Radiation doses were tracked intraprocedurally. RESULTS: Critical details, including structural changes in the PED and LVIS Blue and position and movement of the microcatheter tip within the coil mass, were more readily apparent in Hi-Def mode. Skin-dose mapping indicated that Hi-Def mode limited radiation exposure to the smaller FOV of the treatment area. CONCLUSIONS: Visualization of device structures was much improved in the high-resolution Hi-Def mode, leading to easier, more controlled deployment of stents and coils than conventional FPD mode.

OBJECTIVEThe mortality rates for stroke are decreasing, yet it remains a leading cause of disability and the principal neurological diagnosis in patients discharged to nursing homes. The societal and economic burdens of stroke are substantial, with the total annual health care costs of stroke expected to reach $240.7 billion by 2030. Mechanical thrombectomy has been shown to improve functional outcomes compared to medical therapy alone. Despite an incremental cost of $10,840 compared to medical therapy, the improvement in functional outcomes and decreased disability have contributed to the cost-effectiveness of the procedure. In this study the authors describe a physician-led device bundle purchase program implemented for the delivery of stroke care.METHODSThe authors retrospectively reviewed the clinical and radiographic data and device-associated charges of 45 consecutive patients in whom a virtual “stroke bundle” model was used to purchase mechanical thrombectomy devices.RESULTSUse of the stroke bundle to purchase mechanical thrombectomy devices resulted in an average savings per case of $2900.93. Compared to the traditional model of charging for devices à la carte, this represented an average savings of 25.2% per case. The total amount of savings for these initial 45 cases was $130,542.00. Thrombolysis in Cerebral Infarction scale grade 2b or 3 recanalization occurred in 38 patients (84.4%) using these devices.CONCLUSIONSPurchasing devices through a bundled model resulted in substantial cost savings while maintaining the therapeutic efficacy of the procedure, further pushing the already beneficial long-term cost-benefit curve in favor of thrombectomy.

Traditional digital subtraction angiography provides rather limited evaluation of contrast flow dynamics when studying and treating intracranial brain aneurysms. A 1000-frames-per-second photon-counting x-ray detector was used to image detailed iodine-contrast flow patterns in an internal carotid artery aneurysm of a 3D-printed vascular phantom. High-speed imaging revealed differences in vortex and inflow patterns with and without a Pipeline Embolization Device flow diverter in more detail and clarity than could be seen in standard pulsed angiography. Improved temporal imaging has the potential to impact the outcomes of endovascular interventions by allowing clinicians to better understand and act on flow dynamics in real-time.

BackgroundAngiographic parametric imaging (API) is an imaging method that uses digital subtraction angiography (DSA) to characterize contrast media dynamics throughout the vasculature. This requires manual placement of a region of interest over a lesion (eg, an aneurysm sac) by an operator.ObjectiveThe purpose of our work was to determine if a convolutional neural network (CNN) was able to identify and segment the intracranial aneurysm (IA) sac in a DSA and extract API radiomic features with minimal errors compared with human user results.MethodsThree hundred and fifty angiographic images of IAs were retrospectively collected. The IAs and surrounding vasculature were manually contoured and the masks put to a CNN tasked with semantic segmentation. The CNN segmentations were assessed for accuracy using the Dice similarity coefficient (DSC) and Jaccard index (JI). Area under the receiver operating characteristic curve (AUROC) was computed. API features based on the CNN segmentation were compared with the human user results.ResultsThe mean JI was 0.823 (95% CI 0.783 to 0.863) for the IA and 0.737 (95% CI 0.682 to 0.792) for the vasculature. The mean DSC was 0.903 (95% CI 0.867 to 0.937) for the IA and 0.849 (95% CI 0.811 to 0.887) for the vasculature. The mean AUROC was 0.791 (95% CI 0.740 to 0.817) for the IA and 0.715 (95% CI 0.678 to 0.733) for the vasculature. All five API features measured inside the predicted masks were within 18% of those measured inside manually contoured masks.ConclusionsCNN segmentation of IAs and surrounding vasculature from DSA images is non-inferior to manual contours of aneurysms and can be used in parametric imaging procedures.

Purpose: Investigate the use of neuro pressure gradients (NPG) to assess the impact of carotid artery disease on distal flow conditions using 3D printed patient-specific phantoms. Materials and Methods: Seven patients (five various degrees of carotid artery disease, two healthy) underwent 320- detector row CT angiography (Aquilion ONE, Canon Medical Systems). The internal carotid, vertebral, basilar arteries, as well as the Circle of Willis, middle cerebral arteries (MCA), anterior cerebral arteries (ACA), and posterior cerebral arteries (PCA) were segmented using a Vitrea workstation (Vital Images). The patient anatomy was manipulated in Autodesk Meshmixer and each phantom was 3D printed using material that simulates the compliance of vasculature, Tango+, using a Stratasys Eden260V printer. Phantoms were connected in a pulsatile flow loop with physiological flow rates. Distal resistance was manipulated to simulate physiological conditions. The pressure was measured in the proximal internal carotid arteries and the distal right and left MCA to calculate the neuro pressure gradient (NPG). Results: All seven phantoms were successfully tested in the simulated physiological flow loop. Neuro pressure gradients (NPG) were measured in each phantom and demonstrated a dependence on percent stenosis and Circle of Willis anatomy. NPG ranged -0.67 to 1.10 mmHg/cm and moderately correlated with the stenosis grade and location, and the Circle of Willis configuration. Conclusions: We have successfully assessed the feasibility of measuring NPG in 3D printed patient-specific neurovasculature phantoms with carotid artery disease.

Purpose: Angiographic Parametric Imaging (API) based on Digital Subtraction Angiography (DSA) of Intracranial Aneurysms (IA) can provide parameters related to contrast flow. In this study we propose to investigate the use of a Deep Neural Network (DNN) to analyze API parameters to classify IAs as un-treated or treated, quantify the prediction accuracy, and compare its performance with the Naive Bayes (NB) and K-Nearest Neighbor (KNN) algorithms. Materials and Methods: DSA scans were obtained from patients with un-treated and treated IAs. Three datasets were created based on treatment method: coiled, flow-diverted and combined. These scans were analyzed to provide API parameters for the IA and corresponding main artery. IA parameters were normalized to the main artery parameters. Data was augmented by adding Gaussian noise. The DNN, NB and KNN models were trained on API parameters and tested to classify aneurysms as un-treated or treated. This was performed on each dataset for both normalized and un-normalized data. Results: The DNN had an accuracy and ROC AUC of 72.4% and 0.80 respectively on un-normalized coiled data, 87.9% and 0.95 respectively on normalized coiled data, 73.9% and 0.79 respectively on un-normalized flow-diverted data, 85.3% and 0.80 respectively on normalized flow-diverted data, 62.9% and 0.64 respectively on un-normalized combined data, 64.8% and 0.73 respectively on normalized combined data. Conclusions: This study proves feasibility of using DNNs to classify IAs and make other clinical predictions using normalized API data with treatment methods separated, in addition to being more effective than other classifiers.

Purpose: The purpose of this study is to apply targeted Parametric Imaging on aneurysms to quantitatively investigate contrast flow changes at pre-, post-treatment and follow-up with outcome scoring. Methods: The angiograms for 50 patients were acquired, 25 treated with coil embolization and 25 treated using a flow diverter. API was performed by synthesizing the time density curve (TDC) at every pixel. Based on the TDCs, we calculated various parameters for the quantitative characterization of contrast flow through the vascular network and aneurysms and displayed them using color encoded maps. The parameters included were : Time to Peak (TTP), Mean Transit Time (MTT), Time of Arrival (TTA), Peak Height (PH) and Area Under the Curve (AUC). Two Regions of Interest (ROI) were manually marked over the aneurysm dome and the main artery. Average aneurysm parameter values were normalized to those values recorded in the main artery and recorded pre-/post-treatment and follow-up and compared to Raymond Roy scores and flow diverter stent scoring. Results: The normalized mean values were as follows (pre and post treatment): TTP (1.09+/-0.14, 1.55+/-1.36), MTT (1.07+/-0.23, 1.27+/-0.42), TTA (0.14+/-0.15, 0.26+/-0.23), PH (1.2+/-0.54, 0.95+/-0.83) and AUC (1.29+/-0.69, 1.44+/- 1.92). The neural network gave a validation accuracy of 0.8036 with a loss of 0.0927. A receiver operating characteristic curve with an AUC of 0.866 was obtained. Conclusions: API can quantitatively describe the flow in the aneurysm for initial investigation of the radiomics of intracranial aneurysms. It also shows a clear demarcation between pre and post treatment. Statistical modelling and a machine learning network is used to prove the success of our model.

Four-dimensional computed tomography perfusion (CTP) provides the capability to validate angiographic parametric imaging (API) when locating infarct core. Similar results between these two methods could indicate API can be used to determine whether infarct core has changed following reperfusion procedures. CTP data from 20 patients treated for ischemic strokes was retrospectively collected and loaded into a Vitrea software to locate cerebral infarct tissue. The CTP data was then used to simulate anteroposterior (AP), lateral, and planar digital subtraction angiograms (DSA) for each time period through the perfusion scan. These simulated DSA sequences were used to generate API maps related to mean transit time (MTT), bolus arrival time (BAT), time to peak (TTP), area under the curve (AUC), and peak height (PH) parameters throughout the brain. Contralateral hemisphere comparisons of these values were conducted to determine infarct regions. The infarct regions from the Vitrea and API software were compared using a region of interest overlay method. For all patients, contralateral hemisphere percent differences of 40% for MTT, 20% for BAT, 35% for TTP, 55% for AUC, and 50% for PH are consistent with infarct regions. Using these percentages, the accuracy of API in labeling infarct tissue for the AP, lateral, and planar views is 84%, 70%, and 78% respectively. API conducted on CTP data from stroke patients successfully identified infarct tissue using AP and planar DSA’s. Lateral DSA studies indicate future work is necessary for improved results. This validates API is a feasible method for locating infarct core after reperfusion procedures.

BackgroundComputer modeling of endovascular coiling intervention for intracranial aneurysm could enable a priori patient-specific treatment evaluation. To that end, we previously developed a finite element method (FEM) coiling technique, which incorporated simplified assumptions. To improve accuracy in capturing real-life coiling, we aimed to enhance the modeling strategies and experimentally test whether improvements lead to more accurate coiling simulations.MethodsWe previously modeled coils using a pre-shape based on mathematical curves and mechanical properties based on those of platinum wires. In the improved version, to better represent the physical properties of coils, we model coil pre-shapes based on how they are manufactured, and their mechanical properties based on their spring-like geometric structures. To enhance the deployment mechanics, we include coil advancement to the aneurysm in FEM simulations. To test if these new strategies produce more accurate coil deployments, we fabricated silicone phantoms of 2 patient-specific aneurysms in duplicate, deployed coils in each, and quantified coil distributions from intra-aneurysmal cross-sections using coil density (CD) and lacunarity (L). These deployments were simulated 9 times each using the original and improved techniques, and CD and L were calculated for cross-sections matching those in the experiments. To compare the 2 simulation techniques, Euclidean distances (dMin, dMax, and dAvg) between experimental and simulation points in standardized CD-L space were evaluated. Univariate tests were performed to determine if these distances were significantly different between the 2 simulations.ResultsCoil deployments using the improved technique agreed better with experiments than the original technique. All dMin, dMax, and dAvg values were smaller for the improved technique, and the average values across all simulations for the improved technique were significantly smaller than those from the original technique (dMin: p = 0.014, dMax: p = 0.013, dAvg: p = 0.045).ConclusionIncorporating coil-specific physical properties and mechanics improves accuracy of FEM simulations of endovascular intracranial aneurysm coiling.

BackgroundThe purpose of this cross-sectional study was to determine the percentage of the US population with 60 min ground or air access to accredited or state-designated endovascular-capable stroke centers (ECCs) and non-endovascular capable stroke centers (NECCs) and the percentage of NECCs with an ECC within a 30 min drive.MethodsStroke centers were identified and classified broadly as ECCs or NECCs. Geographic mapping of stroke centers was performed. The population was divided into census blocks, and their centroids were calculated. Fastest air and ground travel times from centroid to nearest ECC and NECC were estimated.ResultsOverall, 49.6% of US residents had 60 min ground access to ECCs. Approximately 37.7% (113 million) lack 60 min ground or air access to ECCs. Approximately 84.4% have 60 min access to NECCs. Ground-only access was available to 77.9%. Approximately 738 NECCs (45.4%) had an ECC within a 30 min drive.ConclusionNearly one-third of the US population lacks 60 min access to endovascular stroke care, but this is highly variable. Transport models and planning of additional centers should be tailored to each state depending on location and proximity of existing facilities.

Background Radial loops are rare congenital radial artery anomalies that may pose a significant challenge to successful transradial neuroangiography. In this case series, we describe the anatomy and frequency of radial artery loops and provide a technique for successful navigation of this anatomic anomaly. Methods We reviewed our database of radial diagnostic or interventional neuroangiographic procedures to identify cases in which a radial loop was encountered during the procedure. The loop pattern, the presence of an associated recurrent radial artery branch, navigation technique, and procedure-related complications were recorded. A descriptive analysis was performed. Results A total of 997 transradial approach procedures were performed over a 9-month period. A radial loop was identified in 10 (1.0%) patients. The average age was 68.6 ± 14.3 years. A microcatheter advanced over a microwire was used to navigate the loop and avoid entry into the recurrent branch. A diagnostic neuroangiographic procedure was performed successfully in 8 cases and an intervention was performed successfully in 1 case. A 360° loop was present in 2 of these cases. In each case, transradial access was performed successfully. In 1 other diagnostic case, transradial access was aborted, and the femoral artery was accessed to perform the procedure. Conclusions A radial loop was present in 1% of the cases in this series. Our technical results suggest that this anomaly should not be considered a contraindication to transradial neuroangiography because the procedure was successfully performed in most (9 of 10) cases using a microcatheter system to navigate the loop.