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Spinal schwannomas are rare nerve root tumors that typically produce subtle symptoms from nerve root compression. These tumors are known to be heterogeneously hyperintense on T2-weighted MRI and avidly enhance with contrast. However, here we describe an L5 spinal schwannoma in a 66-year-old woman that was hypointense on T2-weighted imaging with other radiographic findings more closely aligning with a vascular lesion. The neuroradiologic characteristics on MRI, time resolved MR angiography, and catheter digital subtraction angiography are presented. The patient underwent a full workup for possible dural arteriovenous fistula and thrombosed venous varix before the nerve sheath tumor was discovered intraoperatively and confirmed as a schwannoma on histopathology.

BackgroundAccess to endovascular thrombectomy (EVT) is relatively limited. Hub‐and‐spoke networks seek to transfer appropriate large‐vessel occlusion stroke candidates to EVT‐capable hubs. However, some patients are ineligible upon hub arrival, and factors that drive transfer inefficiencies are not well described. We sought to quantify EVT transfer efficiency and identify reasons for EVT ineligibility.MethodsConsecutive EVT candidates presenting to 25 spokes from 2018 to 2020 with pretransfer computed tomography angiography‐defined large‐vessel occlusion and Alberta Stroke Program Early Computed Tomography Score of ≥6 were identified from a prospectively maintained database. Outcomes of interest included hub EVT, reasons for EVT ineligibility, and 90‐day modified Rankin scale score of ≤2.ResultsAmong 258 patients, the median age was 70 years (interquartile range, 60–81 years); 50% were women. A total of 56% were ineligible for EVT after hub arrival. Cited reasons were large established infarct (49%), mild symptoms (33%), recanalization (6%), distal occlusion (5%), subocclusive lesion (3%), and goals of care (3%). Late window patients (last known well >6 hours) were more likely to be ineligible (67% versus 43%;PP=0.04), had lower National Institutes of Health Stroke Scale score (10 versus 16;PPPP=0.04) compared with eligible patients. EVT ineligibility independently reduced the odds of 90‐day modified Rankin scale score of ≤2 (adjusted odds ratio, 0.26; 95% CI, 0.12–0.56;P=0.001) when controlling for age, National Institutes of Health Stroke Scale score, and last known well‐to‐hub arrival time.ConclusionsAmong patients transferred for EVT, there are multiple reasons for ineligibility upon hub arrival, with most excluded for infarct growth and mild symptoms. Understanding factors that drive transfer inefficiencies is important to improve EVT access and outcomes.

Despite advances in clinical diagnosis and increasing numbers of patients eligible for revascularisation, ischaemic stroke remains a significant public health concern accounting for 3.3 million deaths annually. In addition to recanalisation therapy, patient outcomes could be improved through cerebroprotection, but all translational attempts have remained unsuccessful. In this narrative review, we discuss potential reasons for those failures. We then outline the diverse, multicellular effects of ischaemic stroke and the complex temporal sequences of the pathophysiological cascade during and following ischaemia, reperfusion, and recovery. This evidence is linked with findings from prior cerebroprotective trials and interpreted for the modern endovascular era. Future cerebroprotective agents that are multimodal and multicellular, promoting cellular and metabolic health to different targets at time points that are most responsive to treatment, might prove more successful.

Vertebrovertebral arteriovenous fistulas (VVAVFs) are rare entities that lack consensus guidelines for their management. Our case describes the successful treatment of a traumatic VVAVF via a contralateral deconstructive endovascular approach. A 64-year-old female presented following a traumatic fall. Computed tomography angiogram highlighted a 2 cm pseudoaneurysm of the right vertebral artery (VA) with epidural contrast enhancement and a hematoma with flow voids within the epidural space. Digital subtraction angiography showed a VVAVF at C2-3 with retrograde filling of the distal right VA. Having undergone several unsuccessful passes of the proximal dissection flap in the right VA, the patient underwent a contralateral deconstructive approach with correction of the VVAVF without complication. The remaining feeding branches had occluded after 1 week. The patient made a complete recovery without neurological sequelae at 3-month follow-up.

Background and purposeWe evaluate whether non-haemorrhagic imaging markers (NHIM) (white matter hyperintensity patterns, lacunes and enlarged perivascular spaces (EPVS)) can discriminate cerebral amyloid angiopathy (CAA) from hypertensive cerebral small vessel disease (HTN-cSVD) among patients with isolated lobar intracerebral haemorrhage (isolated-LICH).MethodsIn patients with isolated-LICH, four cSVD aetiologic groups were created by incorporating the presence/distribution of NHIM: HTN-cSVD pattern, CAA pattern, mixed NHIM and no NHIM. CAA pattern consisted of patients with any combination of severe centrum semiovale EPVS, lobar lacunes or multiple subcortical spots pattern. HTN-cSVD pattern consisted of any HTN-cSVD markers: severe basal ganglia PVS, deep lacunes or peribasal ganglia white matter hyperintensity pattern. Mixed NHIM consisted of at least one imaging marker from either pattern. Our hypothesis was that patients with HTN-cSVD pattern/mixed NHIM would have a higher frequency of left ventricular hypertrophy (LVH), which is associated with HTN-cSVD.ResultsIn 261 patients with isolated-LICH, CAA pattern was diagnosed in 93 patients, HTN-cSVD pattern in 53 patients, mixed NHIM in 19 patients and no NHIM in 96 patients. The frequency of LVH was similar among those with HTN-cSVD pattern and mixed NHIM (50% vs 39%, p=0.418) but was more frequent in HTN-cSVD pattern compared with CAA pattern (50% vs 20%, pConclusionAmong patients with isolated-LICH, NHIM may help differentiate HTN-cSVD from CAA, using LVH as a marker for HTN-cSVD.

Background The Woven EndoBridge (WEB) device was explicitly designed for wide-neck intracranial bifurcation aneurysms. Small-scale reports have evaluated the off-label use of WEB devices for the treatment of sidewall aneurysms, with promising outcomes. Purpose To compare the angiographic and clinical outcomes of the WEB device for the treatment of sidewall aneurysms compared with the treatment of bifurcation aneurysms. Materials and Methods A retrospective review of the WorldWideWEB Consortium, a synthesis of retrospective databases spanning from January 2011 to June 2021 at 22 academic institutions in North America, South America, and Europe, was performed to identify patients with intracranial aneurysms treated with the WEB device. Characteristics and outcomes were compared between bifurcation and sidewall aneurysms. Propensity score matching (PSM) was used to match by age, pretreatment ordinal modified Rankin Scale score, ruptured aneurysms, location of aneurysm, multiple aneurysms, prior treatment, neck, height, dome width, daughter sac, and incorporated branch. Results A total of 683 intracranial aneurysms were treated using the WEB device in 671 patients (median age, 61 years [IQR, 53-68 years]; male-to-female ratio, 1:2.5). Of those, 572 were bifurcation aneurysms and 111 were sidewall aneurysms. PSM was performed, resulting in 91 bifurcation and sidewall aneurysms pairs. No significant difference was observed in occlusion status at last follow-up, deployment success, or complication rates between the two groups. Conclusion No significantly different outcomes were observed following the off-label use of the Woven EndoBridge, or WEB, device for treatment of sidewall aneurysms compared with bifurcation aneurysms. The correct characterization of the sidewall aneurysm location, neck angle, and size is crucial for successful treatment and lower retreatment rate. © RSNA, 2022 See also the editorial by Hetts in this issue.

Background and purpose Previous studies suggest that mechanisms and outcomes in patients with COVID-19-associated stroke differ from those in patients with non-COVID-19-associated strokes, but there is limited comparative evidence focusing on these populations. The aim of this study, therefore, was to determine if a significant association exists between COVID-19 status with revascularization and functional outcomes following thrombectomy for large vessel occlusion (LVO), after adjustment for potential confounding factors. Methods A cross-sectional, international multicenter retrospective study was conducted in consecutively admitted COVID-19 patients with concomitant acute LVO, compared to a control group without COVID-19. Data collected included age, gender, comorbidities, clinical characteristics, details of the involved vessels, procedural technique, and various outcomes. A multivariable-adjusted analysis was conducted. Results In this cohort of 697 patients with acute LVO, 302 had COVID-19 while 395 patients did not. There was a significant difference (p < 0.001) in the mean age (in years) and gender of patients, with younger patients and more males in the COVID-19 group. In terms of favorable revascularization (modified Thrombolysis in Cerebral Infarction [mTICI] grade 3), COVID-19 was associated with lower odds of complete revascularization (odds ratio 0.33, 95% confidence interval [CI] 0.23-0.48; p < 0.001), which persisted on multivariable modeling with adjustment for other predictors (adjusted odds ratio 0.30, 95% CI 0.12-0.77; p = 0.012). Moreover, endovascular complications, in-hospital mortality, and length of hospital stay were significantly higher among COVID-19 patients (p < 0.001). Conclusion COVID-19 was an independent predictor of incomplete revascularization and poor functional outcome in patients with stroke due to LVO. Furthermore, COVID-19 patients with LVO were more often younger and had higher morbidity/mortality rates.

Introduction Direct carotid‐cavernous fistulas (dCCF) are acquired, abnormal high‐flow connections between the internal carotid artery and cavernous sinus. Interventions are often required due to the high risk of incipient morbidity and mortality if left untreated. Treatment approaches have rapidly evolved over time, and have included the use of detachable balloons, liquid embolic agents, and coil embolization through transarterial, transvenous, or combined approaches. Case series level data support an emerging role for the use of flow diversion (FD) as a stand‐alone or adjunctive treatment in dCCFs. We describe a case of FD use as an adjunctive treatment in a patient with a treatment‐resistant dCCF, and review the literature on FD use in dCCF. Methods We describe the clinical course, imaging findings, and outcomes of a 25‐year old patient who presented with a traumatic carotid‐cavernous fistula requiring multiple interventions. We also performed a literature review of Pubmed and Embase databases using combinations of MeSH and key terms to include all relevant full‐text publications of FD use in the treatment of dCCFs, up to and including February 2022. Results Our patient achieved angiographic cure and significant improvement in symptoms at 6‐month follow‐up. A total of 24 papers were identified and included, for a total number of 53 cases (23 male, 23 female, 7 unspecified). The median age of patients was 44 years (Interquartile range (IQR) 23–62). The etiology of the dCCF was traumatic (acute or as a delayed presentation) in 31 cases (58%), spontaneous in 10 cases (19%), and iatrogenic in 12 cases (23%). FD was the primary mode of treatment of the CCF in approximately half of cases (27, 51%), and was a stand‐alone treatment modality in one third of cases (18, 34%). The median number of FD devices used on initial treatment was 1 device, though retreatment was needed in 42% of cases.Angiographic resolution was achieved in 90% of cases at a median follow‐up duration of 6 months.One half of all patients had complete resolution of symptoms and a further third noted clinical improvement in at least some of their symptoms. In 10% of cases, symptoms persisted, or other complications developed that were attributed to concurrent injuries. Conclusions Treatment approaches for dCCFs have evolved over time as safer and more effective treatments become available. There is an emerging role for FD as a safe stand‐alone or adjunctive treatment option for dCCFs. Our case further supports its role in treatment‐resistant fistulas with high‐risk features. As treatment approaches continue to evolve, prospective randomized data is needed to better establish the role of flow divertors among the hierarchy of available treatment options for dCCFs.

This study aimed to investigate the influence of stroke lesions in pre-defined highly interconnected (rich club) brain regions on functional outcome post-stroke, determine their spatial specificity and explore the effects of biological sex on their relevance.We analyzed MRI data recorded at index stroke and ∼3-months modified Rankin Scale (mRS) data from patients with acute ischemic stroke (AIS) enrolled in the multisite MRI-GENIE study. Structural stroke lesions were spatially normalized and parcellated into 108 atlas-defined bilateral (sub)cortical brain regions. Unfavorable outcome (mRS>2) was modeled in a Bayesian logistic regression framework that relied on both lesion location, as well as the covariates: age, sex, total DWI lesion volume and comorbidities. Effects of individual brain regions were captured as two compound effects for (i) six bilateral rich club and (ii) all further non-rich club regions. Via model comparisons, we first tested whether the rich club region model was superior to a baseline model considering clinical covariates and lesion volume only. In spatial specificity analyses, we randomized the split into “rich club” and “non-rich club” regions and compared the effect of the actual rich club regions to the distribution of effects from 1,000 combinations of six random regions. In sex-specific analyses, we introduced an additional hierarchical level in our model structure to compare male and female-specific rich club region effects.A total of 822 patients (age: 64.7 (standard deviation: 15.0), 39% women, 27.7% with mRS>2) were analyzed. The rich club model substantially outperformed the baseline model (weights of model comparison: rich club model: 0.96; baseline: 0.04). Rich club regions had substantial relevance in explaining unfavorable functional outcome (mean of posterior distribution: 0.08, area under the curve: 0.8). In particular, the rich club-combination had a higher relevance than 98.4% of random constellations (15/1,000 random constellations with higher mean posterior values). Among the these 15 random constellations with higher means, the most frequently selected regions were the inferior temporal gyrus (posterior division, 8/15), the putamen (8/15), the cingulate gyrus (7/15) and the superior parietal lobule (6/15). Rich club regions were substantially more important in explaining long-term outcome in women than in men (mean of the difference distribution:-0.107, 90%-HDPI:-0.193 to -0.0124).Lesions in rich club regions were associated with increased odds of unfavorable outcome. These effects were spatially specific, i.e., the majority of random combinations of six regions had comparably smaller effects on long-term outcome. Effects were substantially more pronounced in women.

Introduction Pure arterial malformations are dilated, overlapping, and tortuous arteries forming a mass of arterial loops without a venous component. These malformations are rare, with limited cases reported in the literature. Affecting any of the intracranial arteries, they are usually found incidentally and often have a benign course. Methods We present a case of a pure arterial malformation in a young female with hyperprolactinemia. Furthermore, we review the literature and provide an updated summary of these malformations. Results A 28‐year‐old female with a history of infantile hemangiomas, polycystic ovary syndrome, and hyperprolactinemia presented with acne, mild hirsutism, and galactorrhea. Her neurological exam was normal. Magnetic Resonance Imaging (MRI) of the brain with and without contrast ruled out a prolactinoma but revealed a 3 cm vascular malformation at the margin of the left cavernous sinus extending posteriorly into the anterior left perimesencephalic cistern. Initial differentials included a pial arteriovenous malformation or less likely a dural arteriovenous fistula. She underwent a diagnostic cerebral angiogram which revealed a pure arterial malformation without arteriovenous shunting. This was composed of dysplasia of the left posterior communicating artery and anterior choroidal arteries. Stenosis of the left internal carotid artery distally with collateral support into the left anterior cerebral artery and middle cerebral artery was also noted. Lesser changes were noted in the right side with reconstitution of the right anterior cerebral artery from collaterals. Genetic testing for vascular malformation syndromes, including genes known to be associated with hereditary hemorrhagic telangiectasia, was negative. Repeat MRI/MRA done 8 months from the initial scan was stable with no abnormal large arterial venous shunting or definite saccular aneurysm formation noted. Conclusions Although rare, pure arterial malformations should be considered in the differential diagnosis for patients presenting with a cranial vascular malformation. Management of these lesions is usually conservative given their lack of arteriovenous shunting and low risk of rupture, with only a few cases undergoing surgery or endovascular treatment.

Introduction As more large vessel occlusion stroke patients are treated with endovascular thrombectomy (EVT), understanding the pathophysiology of reperfusion injury and the risks of hemorrhagic transformation (HT) are increasingly important. Pre‐EVT infarct topography may have implications for acute interventional treatments such as stenting, and post thrombectomy care such as antithrombotic choice. We sought to quantify region‐specific volumes of infarcted tissue on pre‐EVT MRI, understand their importance for HT, and identify associations with clinical and imaging characteristics. Methods Patients with pre‐EVT MRI were identified retrospectively from a prospectively maintained database. Each patient’s diffusion weighted sequence underwent manual infarct delineation and was registered to a standard space for overlay with cortical, subcortical, and white matter atlases. Structure‐specific lesion volumes were determined. HT was defined as PH1 or PH2 hemorrhage by ECASS criteria. Variables with p< 0.10 in univariate analyses were included in multivariable models. Logistic regression was performed for associations with hemorrhagic transformation and linear regressions for infarct volumes. Results 165 participants [median age 69 years (interquartile range, IQR 56–79), 56% women] were identified. Risk factors included hypertension (70%), diabetes (20%), atrial fibrillation (34%), and prior stroke/TIA (13%). 52% were treated with intravenous alteplase; 70% achieved TICI 2b‐3 reperfusion. HT occurred in 8%. Pre‐EVT infarct volumes [median (IQR)] were 22 cc (12‐43 cc) for total, 11 cc (6‐19 cc) for white matter, 5 cc (1‐19 cc) for cortex, and 3 cc (1‐6 cc) for basal ganglia. Pre‐EVT infarcts [median (IQR)] were made up of 48% (38‐60%) white matter, 23% (6‐47%) cortex, and 15% (4‐28%) basal ganglia. Paramagnetic sequences showed 3% had petechial hemorrhage and 40% had susceptibility vessel sign. Basal ganglia infarct volume was independently associated with HT (OR = 1.342, 95%CI = 1.002,1.797) in a model including white matter infarct volume, cortex infarct volume, smoking, and puncture‐recanalization time. Basal ganglia infarct volume was linked to susceptibility vessel sign (Beta = 0.233, p = 0.006) and NIHSS (Beta = 0.220, p = 0.012), when controlling for total infarct volume. Conclusions In this cohort, greater basal ganglia infarct volume was associated with a higher risk of hemorrhagic transformation, even when accounting for infarct volume in other regions. Susceptibility vessel sign was associated with basal ganglia infarct volume, which may be related to acute middle cerebral artery thrombus occlusion of perforators. These findings require further study in larger cohorts.

Introduction: Predicting individual outcomes post-stroke with the highest possible accuracy is a crucial steppingstone in the realization of precision medicine. We here evaluated various types of lesion information in their capacity to predict stroke severity in a large cohort of patients with acute ischemic stroke. Methods: A total of 1,075 patients of the MRI-GENIE study [age: 64.2(14.7), 38% women] contributed to analyses (N=792 as train and N=283 as test sample). We employed ridge regression with hyperparameter optimization and nested five-fold cross-validation to predict acute NIHSS-based stroke severity. Our baseline model considered DWI lesion volume. Further models tested structural lesion location, indirect structural and functional lesion connectivity, individually and combined with lesion volume. Data was preprocessed by principal component analysis (PCA), retaining 95% of the variance of the original data. Model performance was compared in terms of explained variance (R-squared) and 95% confidence intervals in the outer loop of the training set and the test set. Results: Structural lesion connectivity enabled the highest prediction performance in the test set ( Figure 1 ). Prediction performance did not change notably with inclusion of lesion volume information. This contrasted with the combination of functional lesion connectivity and lesion volume that achieved a substantially higher prediction performance compared to functional lesion connectivity or lesion volume in isolation. Lesion location resulted in a prediction performance that was in the range of lesion volume alone and significantly lower than the ones of structural or functional connectivity with lesion volume. Conclusions: Structural connectivity facilitated the most convincing prediction of stroke severity. The capacity of functional lesion connectivity was substantially improved by the inclusion of lesion volume, indicating both represent complementary information.

Introduction: Patients with baseline disability account for up to one-third of stroke presentations. Despite growing evidence supporting their benefit from endovascular thrombectomy (EVT), there remains controversy in treatment selection. We compared the long-term outcomes and the likelihood of comfort care for large vessel occlusion (LVO) stroke patients who presented with severe baseline disability treated with EVT versus medical management. Methods: Individuals who presented with LVO were identified from a prospectively maintained database from January 2017 to December 2020. Severe baseline disability was defined as modified Rankin Scale (mRS) 3-5. Delta mRS was defined as the difference between baseline and 90-day mRS. Logistic and ordinal regressions were performed to evaluate the relationships between EVT and outcomes. Results: A total of 175/1007 (17%) patients were identified with severe baseline disability. The median age was 82 (IQR 70-89), and 59% were female. Thirty-two (18%) patients with severe baseline disability were treated with EVT. EVT was independently associated with improved delta mRS (B=-1.048; 95%CI=-1.777,-0.318; p=0.005) when accounting for age and NIHSS. However, EVT did not reduce the odds of transitioning to comfort care (aOR=0.794; 95%CI=0.347,1.818; p=0.585) when accounting for age and NIHSS. Seventy-six (43%) patients with severe baseline disability were transitioned to comfort care. Of the 99 patients who were not transitioned to comfort care, 18 were treated with EVT. In this subgroup not transitioned to comfort care, EVT was independently associated with improved delta mRS (B=-2.794; 95%CI=-4.002,-1.586; p Conclusions: Among patients with severe baseline disability, EVT is associated with less post-stroke accumulated disability without limiting transitions to comfort care. EVT is compatible with goal-concordant care in patients with severe baseline disability; it should not be routinely withheld on the sole basis of baseline disability.

Introduction: Deep learning (DL) has allowed for substantial progress in many, often machine vision-focused medical scenarios. Since DL models typically require 10 5 -10 7 examples, it is currently unknown whether DL can also enhance predictions of outcomes post-stroke in real-world samples of stroke patients that are several magnitudes smaller. We here compared the capacities of linear and DL algorithms regarding their prediction of stroke severity. Methods: Our analyses relied on a total of 1435 patients assembled from the MRI-GENIE study and a Massachusetts General Hospital-based study. The primary outcome was acute NIHSS-based stroke severity, which we predicted by means of lesion location. We automatically derived lesion segmentations from DWI scans, performed spatial normalization and principal component analysis (PCA), retaining 95% of the variance of the original data. We then separated a train, validation, and test set, of sizes 918, 230, and 287 respectively. We downsampled the train set to 100, 300, and 900 and learned to predict the NIHSS score for each sample size with regularized linear regression and an 8-layered neural network. We selected hyperparameters on the validation set and conducted 500 dataset splits. We here report explained variance (R-squared) in the test set. Results: While linear regression performed favorably for a sample size of 100 patients (R-squared=0.28), DL started to significantly outperform linear regression when trained on 900 patients (R-squared=0.34, Figure 1 ). Average prediction performance improved by ~20% when increasing the sample size 9x. Conclusions: For sample sizes of ~1000 patients, DL showed a more convincing prediction performance for stroke severity than typically employed linear methods. Our findings suggest the existence of non-linear relationships between lesion location and outcome post-stroke that can be utilized for an improved prediction performance once samples are reasonably large.

Introduction: Coma is an unresponsive state of disordered consciousness characterized by impaired arousal and awareness. While coma has been studied in the context of traumatic brain injury, the epidemiology and pathophysiology of coma in ischemic stroke has been underexplored. We sought to characterize the incidence and clinical features of coma as a presentation of large vessel occlusion (LVO) stroke. Methods: Individuals who presented with LVO were identified from July 2018 to December 2020. Coma was defined as an unresponsive state of impaired arousal and awareness, operationalized as a score of 3 on NIHSS item 1a: responds only with reflex motor or autonomic effects or totally unresponsive, flaccid, and areflexic. Results: A total of 28/638 (4.4%) patients with large vessel occlusion stroke were identified as presenting with coma. The median age was 65 (IQR 48-78), and 57% were female. The median NIHSS was 32 (IQR 29-34). Occlusion locations included basilar (10), vertebral (2), P1 posterior cerebral (2), internal carotid (4), M1 middle cerebral (6), and M2 middle cerebral arteries (4). In all 14 patients with anterior LVO, the acute LVO was unilateral. Of these 14, 6 had evidence of acute or chronic stroke involving the contralateral hemisphere; 1 experienced seizure; 1 experienced cardiac arrest; and 1 had chronic occlusion of the contralateral ICA. Overall, 20/28 died during the admission. Of those who died, 9 presented with anterior LVO and 11 with posterior LVO. Eight patients were treated with EVT. For those not treated, reasons included established infarct with ASPECTS Conclusions: It is not uncommon for patients with LVO stroke to present with coma, and 65% of patients not treated with EVT had delayed presentations or large established infarcts, emphasizing the need for maintaining a high index of suspicion. While more commonly thought to result from posterior LVO, coma in our cohort was similarly likely to result from anterior LVO. Further study of these patients may shed light on the pathophysiology of coma. Efforts to improve early diagnosis and care are crucial given their poor outcomes.

Introduction: With continued expansion in indications for endovascular thrombectomy (EVT), understanding the pathophysiology of reperfusion injury and the risks of hemorrhagic transformation (HT) becomes increasingly important. Pre-EVT infarct topography may have implications for treatment decisions acutely (e.g. stenting), and with post EVT care (e.g. antithrombotics). We sought to quantify region-specific volumes of infarcted tissue on pre-EVT MRI, understand their importance for HT, and identify associations with clinical and imaging characteristics. Methods: Patients with pre-EVT MRI were identified from a prospectively maintained database. Each patient’s diffusion weighted sequence underwent manual infarct delineation and was registered to a standard space for overlay with cortical, subcortical, and white matter atlases. HT was defined as ECASS PH1 or PH2. Variables with p Results: A total of 165 participants [median age 69 (IQR 56-79), 56% women] were identified. Intravenous alteplase was administered to 52%; 70% achieved TICI 2b-3 reperfusion. HT occurred in 8%. The distribution of pre-EVT infarcts was 48% (38-60%) white matter, 23% (6-47%) cortex, and 15% (4-28%) basal ganglia. Pre-EVT infarct volumes [median (IQR)] were 22 cc (12-43 cc) for total, 11 cc (6-19 cc) for white matter, 5 cc (1-19 cc) for cortex, and 3 cc (1-6 cc) for basal ganglia infarct. Paramagnetic sequences showed 3% had petechial hemorrhage and 40% had susceptibility vessel sign. Basal ganglia infarct volume was independently associated with HT (OR=1.342, 95%CI=1.002,1.797) in a model including white matter infarct volume, cortex infarct volume, smoking, and puncture-to-recanalization time. Basal ganglia infarct volume was linked to susceptibility vessel sign (Beta=0.233, p=0.006) and NIHSS (Beta=0.220, p=0.012), when controlling for total infarct volume. Conclusions: Greater basal ganglia infarct volume was associated with a higher risk of HT when accounting for infarct volumes in other regions. Susceptibility vessel sign was associated with basal ganglia infarct volume, which may be related to acute middle cerebral artery perforator occlusion.

The Woven EndoBridge (WEB) device (Terumno Corp. [parent company of Microvention]) was approved by the U.S. Food and Drug Administration as the first intrasaccular device for intracranial aneurysm treatment in December 2018. Its use has become more common since then, but both trial results and postmarket experiences have raised questions about the efficacy in achieving complete aneurysm obliteration. Retreatment after WEB embolization has not been extensively discussed. OBJECTIVE: To discuss the incidence and retreatment of aneurysms after initial WEB embolization. METHODS: Retrospective review across 13 institutions identified all occurrences of WEB retreatment within neurovascular databases. Details regarding demographics, aneurysm characteristics, treatment considerations, clinical outcomes, and aneurysm occlusion were obtained and analyzed. RESULTS: Thirty aneurysms were retreated in 30 patients in a cohort of 342 WEB-treated aneurysms. The retreatment rate was 8.8%. Endovascular methods were used for 23 cases, and 7 were treated surgically. Two aneurysms presented with rehemorrhage after initial WEB embolization. Endovascular treatments included stent-assisted coiling (12), flow diversion (7), coiling (2), PulseRider (Johnson & Johnson)–assisted coiling (1), and additional WEB placement (1). Surgical treatments included primary clipping (6) and Hunterian ligation (1). There were no major complications within the study group. CONCLUSION: WEB retreatments were successfully performed by a variety of techniques, including stent-assisted coiling, clipping, and flow diversion as the most common. These procedures were performed safely with subsequent obliteration of most aneurysms. The potential need for retreatment of aneurysms should be considered during primary WEB treatments.

Background and ObjectivesThe care of patients with large vessel occlusion (LVO) stroke has been revolutionized by endovascular thrombectomy (EVT). While EVT has a large effect size, most patients treated with EVT remain disabled or die within 90 days. A better understanding of outcomes may influence EVT selection criteria, novel therapies, and prognostication. We sought to identify associations between outcomes and brain regions involved in ischemic lesions.MethodsFor this cohort study, consecutive patients with LVO who were treated with EVT and underwent post-EVT MRI were identified from a tertiary referral center (2011–2019). Acute ischemic lesions were manually segmented from diffusion-weighted imaging and spatially normalized. Individual lesions were parcellated (atlas-defined 94 cortical regions, 14 subcortical nuclei, 20 white matter tracts) and reduced to 10 essential lesion patterns with the use of unsupervised dimensionality reduction techniques. Ninety-day modified Rankin Scale (mRS) score (>2) was modeled via bayesian regression, taking the 10 lesion patterns as inputs and controlling for lesion size, age, sex, acute NIH Stroke Scale (NIHSS) score, alteplase, prior stroke, intracerebral hemorrhage, and good reperfusion (Thrombolysis in Cerebral Infarction 2b–3). In comparative analyses, 90-day mRS score was modeled considering covariates only, and compartment-wise relevances for acute stroke severity and 90-day mRS score were evaluated.ResultsThere were 151 patients with LVO identified (age 68 ± 15 years, 52% female). The median NIHSS score was 16 (interquartile range 13–20); 56% had mRS score >2. Lesion locations predictive of 90-day mRS score involved bilateral but left hemispherically more pronounced precentral and postcentral gyri, insular and opercular cortex, and left putamen and caudate (area under the curve 0.91, highest probability density interval [HPDI] covering 90% certainty 0.90–0.92). The lesion location model outperformed the simpler model relying on covariates only (bayesian model comparison of 97% weight to the model with vs 3% weight to the model without lesion location). While lesions affecting subcortical nuclei had the highest relevance for stroke severity (posterior distribution mean 0.75, 90% HPDI 0.256–1.31), lesions affecting white matter tracts had the highest relevance for 90-day mRS score (0.656, 90% HPDI 0.0864–1.12).DiscussionThese data describe the significance for outcomes of specific brain regions involved in ischemic lesions on MRI after EVT. Future work in additional datasets is needed to confirm these granular findings.

Background To date, only 25 cases of cerebral infarction following a bee or wasp sting have been reported. Due to its rarity, undefined pathogenesis, and unique clinical features, we report a case of a 62-year-old man with progressive cerebral infarction following bee stings, possibly related to vasospasm. Furthermore, we review relevant literature on stroke following bee or wasp stings. Case presentation A 62-year-old retired male presented with progressive ischemic stroke after bee stings to the ear and face. Initial magnetic resonance imaging of the brain showed small punctate infarcts in the left medulla oblongata. Head and neck computed tomography angiography showed significant stenosis in the basilar artery and occlusion in the left V4 vertebral artery. The patient received intravenous alteplase (0.9 mg/kg) without symptomatic improvement. Digital subtraction angiography later demonstrated additional near occlusion in the left posterior cerebral artery (PCA). Thrombectomy was considered initially but was aborted due to hemodynamic instability. Repeated CT brain after 24 h showed acute infarcts in the left parieto-occipital region and left thalamus. The near occluded PCA was found to be patent again on magnetic resonance angiography (MRA) 25 days later. This reversibility suggests that vasospasm may have been the underlying mechanism. Unfortunately, the patient had persistent significant neurological deficits after rehabilitation one year later. Conclusion Cerebral infarction following bee stings is rare. There are several proposed pathophysiological mechanisms. While the natural course of this phenomenon is not well characterized, early diagnosis and treatment are essential. Furthermore, it is important to establish standardized care procedures for this unique entity.

Acute ischemic stroke can be subtle to detect on non-contrast computed tomography imaging. We show that a novel artificial intelligence model significantly improves the performance of physicians, including ED physicians, neurologists and radiologists, in identifying and quantifying the volume of acute ischemic stroke lesions. This model may lead to improved clinical decision-making for stroke patients.

Background: The proper imaging modality for use in the selection of patients for endovascular thrombectomy (EVT) presenting in the late window remains controversial, despite current guidelines advocating the use of advanced imaging in this population. We sought to understand if clinicians with different specialty training differ in their approach to patient selection for EVT in the late time window. Methods: We conducted an international survey of stroke and neurointerventional clinicians between January and May 2022 with questions focusing on imaging and treatment decisions of large vessel occlusion (LVO) patients presenting in the late window. Interventional neurologists, interventional neuroradiologists, and endovascular neurosurgeons were defined as interventionists whereas all other specialties were defined as non-interventionists. The non-interventionist group was defined by all other specialties of the respondents: stroke neurologist, neuroradiologist, emergency medicine physician, trainee (fellows and residents) and others. Results: Of 3000 invited to participate, 1506 (1027 non-interventionists, 478 interventionists, 1 declined to specify) physicians completed the study. Interventionist respondents were more likely to proceed directly to EVT (39.5% vs. 19.5%; p < 0.0001) compared to non-interventionist respondents in patients with favorable ASPECTS (Alberta Stroke Program Early CT Score). Despite no difference in access to advanced imaging, interventionists were more likely to prefer CT/CTA alone (34.8% vs. 21.0%) and less likely to prefer CT/CTA/CTP (39.1% vs. 52.4%) for patient selection (p < 0.0001). When faced with uncertainty, non-interventionists were more likely to follow clinical guidelines (45.1% vs. 30.2%) while interventionists were more likely to follow their assessment of evidence (38.7% vs. 27.0%) (p < 0.0001). Conclusion: Interventionists were less likely to use advanced imaging techniques in selecting LVO patients presenting in the late window and more likely to base their decisions on their assessment of evidence rather than published guidelines. These results reflect gaps between interventionists and non-interventionists reliance on clinical guidelines, the limits of available evidence, and clinician belief in the utility of advanced imaging.

Angiographic vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) is associated with delayed cerebral ischemia (DCI)-related cerebral infarction (radiological DCI) and worsened neurological outcome. Transcranial Doppler (TCD) measurements of cerebral blood flow velocity are commonly used after aSAH to screen for vasospasm; however, their association with cerebral infarction is not well characterized. We sought to determine whether time-varying TCD-measured vasospasm severity is associated with cerebral infarction and investigate the performance characteristics of different time/severity cutoffs for predicting cerebral infarction. We conducted a retrospective single-center cohort study of consecutive adult patients with aSAH with at least one TCD study between 2011 and 2020. The primary outcome was radiological DCI, defined as a cerebral infarction developing at least 2 days after any surgical or endovascular intervention without an alternative cause. Cox proportional hazards models were used to examine associations between time-varying vasospasm severity and radiological DCI. Optimal TCD-based time/severity thresholds for predicting radiological DCI were then determined. Of 262 patients with aSAH who underwent TCD studies, 27 (10%) developed radiological DCI. Patients with radiological DCI had higher modified Fisher scale scores and trended toward earlier onset of vasospasm. Adjusted for age, Hunt and Hess scores, and modified Fisher scale scores, the worst-vessel vasospasm severity was associated with radiological DCI (adjusted hazard ratio 1.7 [95% confidence interval 1.1–2.4]). Vasospasm severity within a specific vessel was associated with risk of delayed infarction in the territory supplied by that vessel. Optimal discrimination of patients with radiological DCI was achieved with thresholds of mild vasospasm on days 4–5 or moderate vasospasm on days 6–9, with negative predictive values greater than 90% and positive predictive values near 20%. TCD-measured vasospasm severity is associated with radiological DCI after aSAH. An early, mild TCD-based vasospasm severity threshold had a high negative predictive value, supporting its role as a screening tool to identify at-risk patients.