Multicenter comparison using two AI stroke CT perfusion software packages for determining thrombectomy eligibility.

BACKGROUND: Stroke AI platforms assess infarcted core and potentially salvageable tissue (penumbra) to identify patients suitable for mechanical thrombectomy. Few studies have compared outputs of these platforms, and none have been multicenter or considered NIHSS or scanner/protocol differences. Our objective was to compare volume estimates and thrombectomy eligibility from two widely used CT perfusion (CTP) packages, Viz.ai and RAPID.AI, in a large multicenter cohort. METHODS: We analyzed CTP data of acute stroke patients with large vessel occlusion (LVO) from four institutions. Core and penumbra volumes were estimated by each software and DEFUSE-3 thrombectomy eligibility assessed. Results between software packages were compared and categorized by NIHSS score, scanner manufacturer/model, and institution. RESULTS: Primary analysis of 362 cases found statistically significant differences in both software's volume estimations, with subgroup analysis showing these differences were driven by results from a single scanner model, the Canon Aquilion One. Viz.ai provided larger estimates with mean differences of 8cc and 18cc for core and penumbra, respectively (p<0.001). NIHSS subgroup analysis also showed systematically larger Viz.ai volumes (p<0.001). Despite volume differences, a significant difference in thrombectomy eligibility was not found. Additional subgroup analysis showed significant differences in penumbra volume for the Phillips Ingenuity scanner, and thrombectomy eligibility for the Canon Aquilion One scanner at one center (7 % increased eligibility with Viz.ai, p=0.03). CONCLUSIONS: Despite systematic differences in core and penumbra volume estimates between Viz.ai and RAPID.AI, DEFUSE-3 eligibility was not statistically different in primary or NIHSS subgroup analysis. A DEFUSE-3 eligibility difference, however, was seen on one scanner at one institution, suggesting scanner model and local CTP protocols can influence performance and cause discrepancies in thrombectomy eligibility. We thus recommend centers discuss optimal scanning protocols with software vendors and scanner manufacturers to maximize CTP accuracy.

The first decade of flow diversion for intracranial aneurysms with the Pipeline embolization device.

OBJECTIVE: Flow diverter devices have revolutionized the treatment of intracranial aneurysms (IAs) since their approval in 2011 and have continued to evolve. The devices have been widely adopted across institutions and centers over the past decade; however, long-term follow-up after treatment with the Pipeline embolization device (PED) is not well described in the literature. The authors' institution was among the first to begin using PEDs, allowing them to report their series of patients treated with flow diverters ≥ 10 years ago. In this study, the authors aimed to evaluate the long-term angiographic and clinical outcomes of these patients and review lessons learned along the way. METHODS: The authors performed a retrospective review of their institution's IA database from January 2007 to July 2012. All patients with IAs treated with a PED prior to July 2012 were included. Clinical and angiographic characteristics were extracted. Available angiographic follow-up at 1, 3, 5, and 10 years was reported. RESULTS: A total of 83 patients with 92 aneurysms treated with a PED ≥ 10 years ago were identified and included in the study. The mean aneurysm dome diameter was 9.2 (SD 5.7) mm, the mean aneurysm height was 10.4 (SD 6.8) mm, and the mean neck width was 4.1 (SD 2.4) mm. Only 1 (1.1%) aneurysm was ruptured at presentation. Eight (8.7%) aneurysms were recurrences of previous treatment modalities. The morphology was saccular in 77 (83.7%) aneurysms, fusiform in 14 (15.2%), and blister-like in 1 (1.1%). Among saccular aneurysms, 60 (77.9%) were wide-necked. Seventy-five (81.5%) aneurysms were in the internal carotid artery, 12 (13.0%) were vertebrobasilar, 3 (3.3%) were in the middle cerebral artery, and 2 (2.2%) were in the posterior cerebral artery. Angiographic follow-up at 1, 3, 5, and 10 years was available for 75, 59, 50, and 15 patients, respectively. The complete occlusion rates at 1, 3, 5, and 10 years were 94.7%, 96.6%, 96.0%, and 100%, respectively. The retreatment rates at 1, 3, 5, and 10 years were 8.0%, 6.8%, 8.0%, and 6.7%, respectively. CONCLUSIONS: The authors provide their single-institution series of IA patients treated with a PED ≥ 10 years ago, with the first report of 10-year follow-up for the available patients.

Analysis of craniectomy bone flaps stored in a neurosurgical cryopreservation freezer: microorganism culture results and reimplantation rates.

BACKGROUND: Cryopreservation of bone flaps after decompressive craniectomies is a common practice. A frequent complication after bone flap reimplantation is postoperative infection, so culturing of frozen craniectomy bone flaps is a crucial practice that can prevent patient morbidity and mortality. Although many studies report on infection rates after cranioplasty, no study reports on the results of bone flaps stored in a cryopreservation freezer, reimplanted or otherwise. We sought to analyze the flaps in our medical center's bone bank freezer, including microorganism culture results and reimplantation rates of cryopreserved bone flaps. METHODS: Patients who underwent craniectomy and had bone flaps cryopreserved between January 1, 2016, and July 1, 2022, were included in this retrospective study. Information about bone flap cultures and reimplantation or discard was obtained from a prospectively maintained cryopreservation database. Information including infection rates and mortality was acquired from a retrospective review of patient records. Culture results were obtained for all flaps immediately before cryopreservation and again at the time of reimplantation at the operator's discretion. RESULTS: There were 148 bone flaps obtained from 145 patients (3 craniectomies were bilateral) stored in our center's freezer. Positive culture results were seen in 79 (53.4%) flaps. The most common microorganism genus was Propionibacterium with 47 positive flaps, 46 (97.9%) of which were P. acnes. Staphylococcus was the second most common with 23 positive flaps, of which 8 (34.8%) tested positive for S. epidermidis. Of the 148 flaps, 25 (16.9%) were reimplanted, 116 (78.4%) were discarded, and 7 (4.7%) are still being stored in the freezer. Postcranioplasty infections were seen in 3 (12%) patients who had flap reimplantation. CONCLUSIONS: Considering the substantial number of positive cultures and limited reimplantation rate, we have reservations about the logistical efficiency of cryopreservation for flap storage. Future multicenter studies analyzing reimplantation predictors could help to reduce unnecessary freezing and culturing.

Meta-analysis of overall survival and postoperative neurologic deficits after resection or biopsy of butterfly glioblastoma.

Butterfly glioblastoma (bGBM) is a grade 4 glioma with a poor prognosis. Surgical treatment of these cancers has been reviewed in the literature with some recent studies supporting resection as a safe and effective treatment instead of biopsy and adjuvant therapy. This meta-analysis was designed to determine whether there are significant differences in overall survival (OS) and postoperative neurologic deficits (motor, speech, and cranial nerve) following intervention in patients who underwent tumor resection as part of their treatment, compared to patients who underwent biopsy without surgical resection. A literature search was conducted using PubMed (National Library of Medicine) and Embase (Elsevier) to identify articles from each database's earliest records to May 25, 2021, that directly compared the outcomes of biopsy and resection in bGBM patients and met predetermined inclusion criteria. A meta-analysis was conducted to compare the effects of the two management strategies on OS and postoperative neurologic deficits. Six articles met our study inclusion criteria. OS was found to be significantly longer for the resection group at 6 months (odds ratio [OR] 2.94, 95% confidence interval [CI] 1.23-7.05) and 12 months (OR 3.75, 95% CI 1.10-12.76) than for the biopsy group. No statistically significant differences were found in OS at 18 and 24 months. Resection was associated with an increased rate of postoperative neurologic deficit (OR 2.05, 95% CI 1.02-4.09). Resection offers greater OS up to 1 year postintervention than biopsy alone; however, this comes at the cost of higher rates of postoperative neurologic deficits.

Use of quantitative angiographic methods with a data-driven model to evaluate reperfusion status (mTICI) during thrombectomy.

PURPOSE: Intra-procedural assessment of reperfusion during mechanical thrombectomy (MT) for emergent large vessel occlusion (LVO) stroke is traditionally based on subjective evaluation of digital subtraction angiography (DSA). However, semi-quantitative diagnostic tools which encode hemodynamic properties in DSAs, such as angiographic parametric imaging (API), exist and may be used for evaluation of reperfusion during MT. The objective of this study was to use data-driven approaches, such as convolutional neural networks (CNNs) with API maps, to automatically assess reperfusion in the neuro-vasculature during MT procedures based on the modified thrombolysis in cerebral infarction (mTICI) scale. METHODS: DSAs from patients undergoing MTs of anterior circulation LVOs were collected, temporally cropped to isolate late arterial and capillary phases, and quantified using API peak height (PH) maps. PH maps were normalized to reduce injection variability. A CNN was developed, trained, and tested to classify PH maps into 2 outcomes (mTICI 0,1,2a/mTICI 2b,2c,3) or 3 outcomes (mTICI 0,1,2a/mTICI 2b/mTICI 2c,3), respectively. Ensembled networks were used to combine information from multiple views (anteroposterior and lateral). RESULTS: The study included 383 DSAs. For the 2-outcome classification, average accuracy was 81.0% (95% CI, 79.0-82.9%), and the area under the receiver operating characteristic curve (AUROC) was 0.86 (0.84-0.88). For the 3-outcome classification, average accuracy was 64.0% (62.0-66.0), and AUROC values were 0.85 (0.83-0.87), 0.74 (0.71-0.77), and 0.78 (0.76-0.81) for the mTICI 0,1,2a, mTICI 2b, and mTICI 2c,3 classes, respectively. CONCLUSION: This study demonstrated the feasibility of using hemodynamic information in API maps with data-driven models to autonomously assess intra-procedural reperfusion during MT.

Comparison of effectiveness and outcomes among different thrombectomy techniques in acute basilar artery occlusion: a dual-center experience.

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.

Is Endovascular Therapy for Stroke Cost-Effective Globally? A Systematic Review of the Literature.

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.

Aspiration thrombectomy versus stent retriever thrombectomy as first-line approach for large vessel occlusion (COMPASS): a multicentre, randomised, open label, blinded outcome, non-inferiority trial.

BACKGROUND: Stent retriever thrombectomy of large-vessel occlusion results in better outcomes than medical therapy alone. Alternative thrombectomy strategies, particularly a direct aspiration as first pass technique, while promising, have not been rigorously assessed for clinical efficacy in randomised trials. We designed COMPASS to assess whether patients treated with aspiration as first pass have non-inferior functional outcomes to those treated with a stent retriever as first line. METHODS: We did a multicentre, randomised, open label, blinded outcome, core lab adjudicated non-inferiority trial at 15 sites (ten hospitals and four specialty clinics in the USA and one hospital in Canada). Eligible participants were patients presenting with acute ischaemic stroke from anterior circulation large-vessel occlusion within 6 h of onset and an Alberta Stroke Program Early CT Score of greater than 6. We randomly assigned participants (1:1) via a central web-based system without stratification to either direct aspiration first pass or stent retriever first line thrombectomy. Those assessing primary outcomes via clinical examinations were masked to group assignment as they were not involved in the procedures. Physicians were allowed to use adjunctive technology as was consistent with their standard of care. The null hypothesis for this study was that patients treated with aspiration as first pass achieve inferior outcomes compared with those treated with a stent retriever first line approach. The primary outcome was non-inferiority of clinical functional outcome at 90 days as measured by the percentage of patients achieving a modified Rankin Scale score of 0-2, analysed by intent to treat; non-inferiority was established with a margin of 0·15. All randomly assigned patients were included in the safety analyses. This trial is registered at ClinicalTrials.gov, number: NCT02466893. FINDINGS: Between June 1, 2015, and July 5, 2017, we assigned 270 patients to treatment: 134 to aspiration first pass and 136 to stent retriever first line. A modified Rankin score of 0-2 at 90 days was achieved by 69 patients (52%; 95% CI 43·8-60·3) in the aspiration group and 67 patients (50%; 41·6-57·4) in the stent retriever group, showing that aspiration as first pass was non-inferior to stent retriever first line (pnon-inferiority=0·0014). Intracranial haemorrhage occurred in 48 (36%) of 134 in the aspiration first pass group, and 46 (34%) of 135 in the stent retriever first line group. All-cause mortality at 3 months occurred in 30 patients (22%) in both groups. INTERPRETATION: A direct aspiration as first pass thrombectomy conferred non-inferior functional outcome at 90 days compared with stent retriever first line thrombectomy. This study supports the use of direct aspiration as an alternative to stent retriever as first-line therapy for stroke thrombectomy. FUNDING: Penumbra.

Classification models using circulating neutrophil transcripts can detect unruptured intracranial aneurysm.

BACKGROUND: Intracranial aneurysms (IAs) are dangerous because of their potential to rupture. We previously found significant RNA expression differences in circulating neutrophils between patients with and without unruptured IAs and trained machine learning models to predict presence of IA using 40 neutrophil transcriptomes. Here, we aim to develop a predictive model for unruptured IA using neutrophil transcriptomes from a larger population and more robust machine learning methods. METHODS: Neutrophil RNA extracted from the blood of 134 patients (55 with IA, 79 IA-free controls) was subjected to next-generation RNA sequencing. In a randomly-selected training cohort (n = 94), the Least Absolute Shrinkage and Selection Operator (LASSO) selected transcripts, from which we constructed prediction models via 4 well-established supervised machine-learning algorithms (K-Nearest Neighbors, Random Forest, and Support Vector Machines with Gaussian and cubic kernels). We tested the models in the remaining samples (n = 40) and assessed model performance by receiver-operating-characteristic (ROC) curves. Real-time quantitative polymerase chain reaction (RT-qPCR) of 9 IA-associated genes was used to verify gene expression in a subset of 49 neutrophil RNA samples. We also examined the potential influence of demographics and comorbidities on model prediction. RESULTS: Feature selection using LASSO in the training cohort identified 37 IA-associated transcripts. Models trained using these transcripts had a maximum accuracy of 90% in the testing cohort. The testing performance across all methods had an average area under ROC curve (AUC) = 0.97, an improvement over our previous models. The Random Forest model performed best across both training and testing cohorts. RT-qPCR confirmed expression differences in 7 of 9 genes tested. Gene ontology and IPA network analyses performed on the 37 model genes reflected dysregulated inflammation, cell signaling, and apoptosis processes. In our data, demographics and comorbidities did not affect model performance. CONCLUSIONS: We improved upon our previous IA prediction models based on circulating neutrophil transcriptomes by increasing sample size and by implementing LASSO and more robust machine learning methods. Future studies are needed to validate these models in larger cohorts and further investigate effect of covariates.

Size of ruptured intracranial aneurysms: a systematic review and meta-analysis.

BACKGROUND: There is wide variation in the reported size of ruptured intracranial aneurysms and methods of size estimation. There is widespread belief that small aneurysms < 7 mm do not rupture. Therefore, we performed a systematic review and meta-analysis of the literature to determine the size of ruptured aneurysms according to aneurysm locations and methods of size estimation. METHODS: We searched PubMed, Cochrane, CINAHL, and EMBASE databases using a combination of Medical Subject Headings (MeSH) terms. We included articles that reported mean aneurysm size in consecutive series of ruptured intracranial. We excluded studies limited to a specific aneurysm location or type. The random-effects model was used to calculate overall mean size and location-specific mean size. We performed meta-regression to explain observed heterogeneity and variation in reported size. RESULTS: The systematic review included 36 studies and 12,609 ruptured intracranial aneurysms. Overall mean aneurysm size was 7.0 mm (95% confidence interval [CI 6.2-7.4]). Pooled mean size varied with location. Overall mean size of 2145 ruptured anterior circulation aneurysms was 6.0 mm (95% CI 5.6-6.4, residual I2 = 86%). Overall mean size of 743 ruptured posterior circulation aneurysms was 6.2 mm (95% CI 5.3-7.0, residual I2 = 93%). Meta-regression identified aneurysm location and definition of size (i.e., maximum dimension vs. aneurysm height) as significant determinants of aneurysm size reported in the studies. CONCLUSIONS: The mean size of ruptured aneurysms in most studies was approximately 7 mm. The general wisdom that aneurysms of this size do not rupture is incorrect. Location and size definition were significant determinants of aneurysm size.

Impact of endovascular reperfusion on low National Institutes of Health Stroke Scale score large-vessel occlusion stroke.

INTRODUCTION: Effectiveness of mechanical thrombectomy for mild-deficit stroke due to large-vessel occlusion is controversial. We present a single-center consecutive case series on thrombectomy for large-vessel occlusion mild stroke. We evaluated various thrombectomy parameters to better understand disagreement in the literature. METHODS: Data from a retrospective cohort of large-vessel occlusion mild stroke patients (National Institutes of Health Stroke Scale <6) treated with mechanical thrombectomy over 6 years and 2 months were analyzed. Patients were divided into 2 groups: successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b or 3) and failed reperfusion (modified Thrombolysis in Cerebral Infarction 0,1, or 2a). Ninety-day modified Rankin Scale in-hospital mortality, and symptomatic hemorrhage rates were compared between groups. Multivariate logistic regression was performed to evaluate reperfusion status as a predictor of 90-day favorable (modified Rankin Scale 0-2) and excellent (modified Rankin Scale 0-1) outcomes. RESULTS: We identified 61 patients with large-vessel occlusion mild stroke who underwent thrombectomy. Reperfusion was successful in 49 patients and a failure in 12. The successful group exhibited significantly higher rates of favorable outcome (83.7% vs. 25.0%; p < 0.001) and excellent outcome (69.4% vs.16.7%; p = 0.002) at 90 days. In-hospital mortality was significantly higher in the failure group (41.7% vs.10.2%; p = 0.019). Multivariate logistic regression identified successful reperfusion as a significant predictor (p = 0.001) of 90-day favorable outcome. CONCLUSION: Reperfusion success was significantly associated with improved functional outcomes in large-vessel occlusion mild stroke mechanical thrombectomy. Future studies should consider reperfusion rates when evaluating the effectiveness of thrombectomy against that of medical management in these patients.

Biomarkers from circulating neutrophil transcriptomes have potential to detect unruptured intracranial aneurysms.

BACKGROUND: Intracranial aneurysms (IAs) are dangerous because of their potential to rupture and cause deadly subarachnoid hemorrhages. Previously, we found significant RNA expression differences in circulating neutrophils between patients with unruptured IAs and aneurysm-free controls. Searching for circulating biomarkers for unruptured IAs, we tested the feasibility of developing classification algorithms that use neutrophil RNA expression levels from blood samples to predict the presence of an IA. METHODS: Neutrophil RNA extracted from blood samples from 40 patients (20 with angiography-confirmed unruptured IA, 20 angiography-confirmed IA-free controls) was subjected to next-generation RNA sequencing to obtain neutrophil transcriptomes. In a randomly-selected training cohort of 30 of the 40 samples (15 with IA, 15 controls), we performed differential expression analysis. Significantly differentially expressed transcripts (false discovery rate < 0.05, fold change ≥ 1.5) were used to construct prediction models for IA using four well-known supervised machine-learning approaches (diagonal linear discriminant analysis, cosine nearest neighbors, nearest shrunken centroids, and support vector machines). These models were tested in a testing cohort of the remaining 10 neutrophil samples from the 40 patients (5 with IA, 5 controls), and model performance was assessed by receiver-operating-characteristic (ROC) curves. Real-time quantitative polymerase chain reaction (PCR) was used to corroborate expression differences of a subset of model transcripts in neutrophil samples from a new, separate validation cohort of 10 patients (5 with IA, 5 controls). RESULTS: The training cohort yielded 26 highly significantly differentially expressed neutrophil transcripts. Models using these transcripts identified IA patients in the testing cohort with accuracy ranging from 0.60 to 0.90. The best performing model was the diagonal linear discriminant analysis classifier (area under the ROC curve = 0.80 and accuracy = 0.90). Six of seven differentially expressed genes we tested were confirmed by quantitative PCR using isolated neutrophils from the separate validation cohort. CONCLUSIONS: Our findings demonstrate the potential of machine-learning methods to classify IA cases and create predictive models for unruptured IAs using circulating neutrophil transcriptome data. Future studies are needed to replicate these findings in larger cohorts.

Transverse venous stenting for the treatment of idiopathic intracranial hypertension, or pseudotumor cerebri.

OBJECTIVE Idiopathic intracranial hypertension (IIH) is a commonly occurring disease, particularly among young women of child-bearing age. The underlying pathophysiology for this disease has remained largely unclear; however, the recent literature suggests that focal outflow obstruction of the transverse sinus may be the cause. The purpose of this study was to report one group's early experience with transverse venous sinus stenting in the treatment of IIH and assess its effectiveness. METHODS The authors performed a retrospective chart review to identify patients who had undergone stenting of an outflow-obstructed transverse venous sinus for the treatment of IIH at Gates Vascular Institute between January 2015 and November 2017. Patient demographic data of interest included age, sex, BMI, and history of smoking, hypertension, obstructive sleep apnea, hormonal contraceptive use, and acetazolamide therapy. Each patient's presenting signs and symptoms and whether those symptoms improved with treatment were reviewed. The average opening lumbar puncture (LP) pressure preprocedure, average pressure gradient across the obstructed segment prior to stenting, treatment failure rate (need for shunt placement), and mean follow-up period were calculated. RESULTS Of the 18 patients who had undergone transverse venous stenting for IIH, 16 (88.9%) were women. The mean age of all the patients was 38.3 years (median 38 years). Mean BMI was 34.2 kg/m2 (median 33.9 kg/m2). Presenting symptoms were headache (16 patients [88.9%]), visual disturbances (13 patients [72.2%]), papilledema (8 patients [44.4%]), tinnitus (3 patients [16.7%]), and auditory bruit (3 patients [16.7%]). The mean opening LP pressure pre-procedure was 35.6 cm H2O (median 32 cm H2O). The mean pressure gradient measured proximally and distally to the area of focal obstruction within the transverse sinus was 16.5 cm H2O (median 15 cm H2O). Postprocedurally, 14 patients (77.8%) continued to have headaches; 6 (33.3%) continued to have visual disturbances. No patients continued to have auditory bruit (0%) or papilledema (0%). One patient (5.6%) had new-onset tinnitus postprocedure. Overall improvement of symptoms was noted in 16 patients (88.9%) postprocedure, with 1 patient (5.6%) requiring shunt placement and 2 other patients (11.1%) requiring postprocedural LP to monitor intracranial pressure to determine candidacy for further surgical interventions to treat residual symptoms. The mean duration of follow-up was 194.2 days. CONCLUSIONS Transverse sinus stenting is a rapidly developing technique that has shown good effectiveness and safety in the literature. Authors of the present study found that stenting a flow-obstructed transverse sinus in patients with IIH was a safe and effective way to treat the condition.

Management of acute ischemic stroke due to tandem occlusion: should endovascular recanalization of the extracranial or intracranial occlusive lesion be done first?

OBJECTIVE Acute tandem occlusions of the cervical internal carotid artery and an intracranial large vessel present treatment challenges. Controversy exists regarding which lesion should be addressed first. The authors sought to evaluate the endovascular approach for revascularization of these lesions at Gates Vascular Institute. METHODS The authors performed a retrospective review of a prospectively maintained, single-institution database. They analyzed demographic, procedural, radiological, and clinical outcome data for patients who underwent endovascular treatment for tandem occlusions. A modified Rankin Scale (mRS) score ≤ 2 was defined as a favorable clinical outcome. RESULTS Forty-five patients were identified for inclusion in the study. The average age of these patients was 64 years; the mean National Institutes of Health Stroke Scale score at presentation was 14.4. Fifteen patients received intravenous thrombolysis before undergoing endovascular treatment. Thirty-seven (82%) of the 45 proximal cervical internal carotid artery occlusions were atherothrombotic in nature. Thirty-eight patients underwent a proximal-to-distal approach with carotid artery stenting first, followed by intracranial thrombectomy, whereas 7 patients underwent a distal-to-proximal approach (that is, intracranial thrombectomy was performed first). Thirty-seven (82%) procedures were completed with local anesthesia. For intracranial thrombectomy procedures, aspiration alone was used in 15 cases, stent retrieval alone was used in 5, and a combination of aspiration and stent-retriever thrombectomy was used in the remaining 25. The average time to revascularization was 81 minutes. Successful recanalization (thrombolysis in cerebral infarction Grade 2b/3) was achieved in 39 (87%) patients. Mean National Institutes of Health Stroke Scale scores were 9.3 immediately postprocedure (p < 0.05) (n = 31), 5.1 at discharge (p < 0.05) (n = 31), and 3.6 at 3 months (p < 0.05) (n = 30). There were 5 in-hospital deaths (11%); and 2 patients (4.4%) had symptomatic intracranial hemorrhage within 24 hours postprocedure. Favorable outcomes (mRS score ≤ 2) were achieved at 3 months in 22 (73.3%) of 30 patients available for follow-up, with an mRS score of 3 for 7 of 30 (23%) patients. CONCLUSIONS Tandem occlusions present treatment challenges, but high recanalization rates were possible in the present series using acute carotid artery stenting and mechanical thrombectomy concurrently. Proximal-to-distal and aspiration approaches were most commonly used because they were safe, efficacious, and feasible. Further study in the setting of a randomized controlled trial is needed to determine the best sequence for the treatment approach and the best technology for tandem occlusion.

Clinical and Procedural Predictors of Outcomes From the Endovascular Treatment of Posterior Circulation Strokes.

BACKGROUND AND PURPOSE: Patients with posterior circulation strokes have been excluded from recent randomized endovascular stroke trials. We reviewed the recent multicenter experience with endovascular treatment of posterior circulation strokes to identify the clinical, radiographic, and procedural predictors of successful recanalization and good neurological outcomes. METHODS: We performed a multicenter retrospective analysis of consecutive patients with posterior circulation strokes, who underwent thrombectomy with stent retrievers or primary aspiration thrombectomy (including A Direct Aspiration First Pass Technique [ADAPT] approach). We correlated clinical and radiographic outcomes with demographic, clinical, and technical characteristics. RESULTS: A total of 100 patients were included in the final analysis (mean age, 63.5±14.2 years; mean admission National Institutes of Health Stroke Scale score, 19.2±8.2). Favorable clinical outcome at 3 months (modified Rankin Scale score ≤2) was achieved in 35% of patients. Successful recanalization and shorter time from stroke onset to the start of the procedure were significant predictors of favorable clinical outcome at 90 days. Stent retriever and aspiration thrombectomy as primary treatment approaches showed comparable procedural and clinical outcomes. None of the baseline advanced imaging modalities (magnetic resonance imaging, computed tomographic perfusion, or computed tomography angiography assessment of collaterals) showed superiority in selecting patients for thrombectomy. CONCLUSIONS: Time to the start of the procedure is an important predictor of clinical success after thrombectomy in patients with posterior circulation strokes. Both stent retriever and aspiration thrombectomy as primary treatment approaches are effective in achieving successful recanalization.

Endovascular management of adjacent tandem intracranial aneurysms: utilization of stent-assisted coiling and flow diversion.

BACKGROUND: Tandem intracranial aneurysms are aneurysms located along a single intracranial vessel. Adjacent tandem aneurysms arise within the same vascular segment and their presence often suggests diffuse parent vessel anomaly. Endovascular management of these rare lesions has not been well studied. In this retrospective observational study, we describe our experience treating adjacent tandem intracranial aneurysms with endovascular embolization. METHODS: We retrospectively reviewed records of patients with these lesions who underwent endovascular treatment between 2008 and 2013. RESULTS: Thirteen patients (mean age 60.8 years; 12 women) with 28 adjacent tandem aneurysms were treated during the study timeframe. Aneurysms were located along the clinoidal, ophthalmic, and communicating segments of the internal carotid artery in 12 patients and at the basilar apex in one patient. Average size was 8.4 mm. Six patients (12 aneurysms) were treated by flow diversion via the Pipeline embolization device (PED) and seven (16 aneurysms) by stent-assisted coiling, with coils successfully placed in 11 aneurysms. Clinical follow-up was available for an average of 26.1 months; postprocedural angiography was performed for 12 patients. Complete occlusion was achieved in nine of ten (90 %) PED-treated aneurysms and eight of 11 (72.7 %) treated by stent-assisted coiling (p = 0.44). Two patients treated by stent-assisted coiling required re-coiling for aneurysm recanalization. Overall, modified Rankin scale scores were 0-1 for 12 patients and 3 for one patient. CONCLUSIONS: Adjacent tandem intracranial aneurysms can be safely and effectively treated by either stent-assisted coiling or flow diversion. We prefer PED flow diversion due to better parent vessel reconstruction and lower recanalization risk.

Masked smoothing using separable kernels for CT perfusion images.

BACKGROUND: CT perfusion images have a high contrast ratio between voxels representing different anatomy, such as tissue or vessels, which makes image segmentation of tissue and vascular regions relatively easy. However, grey and white matter tissue regions have relatively low values and can suffer from poor signal to noise ratios. While smoothing can improve the image quality of the tissue regions, the inclusion of much higher valued vascular voxels can skew the tissue values. It is thus desirable to smooth tissue voxels separately from other voxel types, as has been previously implemented using mean filter kernels. We created a novel Masked Smoothing method that performs Gaussian smoothing restricted to tissue voxels. Unlike previous methods, it is implemented as a combination of separable kernels and is therefore fast enough to consider for clinical work, even for large kernel sizes. METHODS: We compare our Masked Smoothing method to alternatives using Gaussian smoothing on an unaltered image volume and Gaussian smoothing on an image volume with vascular voxels set to zero. Each method was tested on simulation data, collected phantom data, and CT perfusion data sets. We then examined tissue voxels for bias and noise reduction. RESULTS: Simulation and phantom experiments demonstrate that Masked Smoothing does not bias the underlying tissue value, whereas the other smoothing methods create significant bias. Furthermore, using actual CT perfusion data, we demonstrate significant differences in the calculated CBF and CBV values dependent on the smoothing method used. CONCLUSION: The Masked Smoothing is fast enough to allow eventual clinical usage and can remove the bias of tissue voxel values that neighbor blood vessels. Conversely, the other Gaussian smoothing methods introduced significant bias to the tissue voxels.

Visual Morbidity in Patients With Ophthalmic Segment Aneurysms Treated With Flow Diverters: A Dual-Center Experience.

BACKGROUND AND OBJECTIVE: Flow diverter (FD) treatment for aneurysms of the ophthalmic segment of the internal carotid artery (ICA) may raise concerns about visual morbidity related to coverage of the ophthalmic artery by the device. Our objective was to evaluate clinical and angiographic outcomes associated with FD treatment of these aneurysms, with particular emphasis on visual morbidity. METHODS: We performed a retrospective analysis of the endovascular databases at 2 US centers to identify consecutive patients with aneurysms along the ophthalmic segment of the ICA that were treated with FDs between January 2010 and December 2022. Baseline demographics, aneurysm characteristics, and periprocedural and postprocedural data, including the occurrence of visual complications, were collected. RESULTS: One hundred and thirteen patients with 113 aneurysms were identified for inclusion in this study. The mean age of the patients was 59.5 ± 12.4 years, and 103 (91.2%) were women. The ophthalmic artery origin was involved in 40 (35.4%) aneurysms, consisting of a neck origin in 33 (29.2%) and a dome origin in 7 (6.2%). New transient visual morbidity during the hospital stay included impaired visual acuity or blurriness in 1 (0.9%) patient, diplopia in 1 (0.9%), and floaters in 1 (0.9%). New transient visual morbidity during follow-up included impaired visual acuity or blurriness in 5 patients (4.4%), diplopia in 3 (2.7%), ipsilateral visual field defect in 1 (0.9%), and floaters in 6 (5.3%). Permanent visual morbidity occurred in 1 patient (0.9%). Among the 101 patients who had angiographic follow-up, the Raymond-Roy occlusion classifications were I (complete aneurysm occlusion) in 85 (84.2%), II (residual neck) in 11 (10.9%), and III (residual aneurysm) in 5 (4.9%). CONCLUSION: In our experience, flow diversion for ICA ophthalmic segment aneurysms resulted in low rates of visual morbidity, which was mostly transient in occurrence.

Stenting for Venous Sinus Stenosis in Patients With Idiopathic Intracranial Hypertension: An Updated Systematic Review and Meta-Analysis of the Literature.

BACKGROUND AND OBJECTIVES: Although venous sinus stenting (VSS) improves cerebrospinal fluid reabsorption and decreases intracranial pressure in patients with idiopathic intracranial hypertension (IIH), the underlying pathophysiology of IIH is not well understood. We present a review and meta-analysis of the literature on VSS for IIH treatment, focusing on the rates of restenosis and symptom recurrence. METHODS: We performed a systematic review of PubMed and Embase databases between January 1, 2011, and December 31, 2021. Articles including ≥5 patients with IIH and venous sinus stenosis treated with VSS and post-treatment rates of restenosis (de novo stenosis at a different anatomic location along the dural sinuses or restenosis within or adjacent to the stent) were selected. Demographic, procedural, and outcomes data were collected and analyzed. Mean values for variables collected were pooled, and a mean value was calculated with a 95% CI. RESULTS: Twenty-four articles were included, comprising 694 patients and 781 VSS cases. The mean age was 33.9 (CI, 31.5-36.2) years. The mean body mass index was 35.3 (CI, 32.9-37.7) kg/m 2 . Before VSS, 98.8% (CI, 96.8%-100.0%) of patients experienced headaches, 87.7% (CI, 80.6%-95.5%) had visual acuity issues, 78.7% (CI, 69.9%-88.5%) had papilledema, 58.3% (CI, 46.0%-73.9%) had tinnitus, and 98.8% (96.4%-100.0%) had symptoms refractory to previous therapies. After VSS, 77.7% (CI, 71.1%-84.95%) experienced symptom improvement and 22.3% (CI, 15.1%-29.0%) had persistent or worsened symptoms. Pooled restenosis rate was 17.7% (CI, 14.9%-20.9%). CONCLUSION: VSS is effective in alleviating IIH signs and symptoms, but the associated high rates of restenosis and persistent symptoms highlight the need for further investigation of this procedure and other adjunctive treatments for IIH.

Preradiosurgical Embolization of Arteriovenous Malformations Reduces Target Volume - The Main Determinant for Complete Obliteration.

BACKGROUND: Embolization and stereotactic radiosurgery (SRS) have increasingly been used to treat complex arteriovenous malformations (AVMs). We studied outcomes of AVM patients treated through a multidisciplinary approach, examined the effect of embolization on SRS success, and analyzed predictors of treatment failure. METHODS: We retrospectively reviewed a prospectively maintained database of patients with AVMs treated with Gamma Knife (Leksell) SRS over an 11-year period. Patients with incomplete medical records and follow-up <2 years were excluded. Demographics, clinical presentation, previous rupture history, angiographic nidus size, Spetzler-Martin (S-M) grade, adjunctive endovascular embolization and microsurgical resection, radiologic evidence of obliteration and hemorrhage, and clinical outcomes (modified Rankin Scale [mRS] scores) were recorded. Radiosurgery-related details including nidus volume and number of sessions and radiosurgery-, embolization-, and resection-associated complications were also recorded. RESULTS: Eighty-three patients (mean age, 41.0 ± 21.3 years) were included. Mean reduction in AVM nidus target volume with endovascular embolization was 66.0 ± 19.7%. S-M grade reduction was achieved in 51.6% cases. Total obliteration after SRS was achieved in 56 AVMs (67.5%) after 2 years, and in 38 (86.4%) after 4 years. Two (2.4%) patients had rehemorrhage after SRS. Overall complication rate was 3.6%. Median angiographic follow-up was 55.5 months. Favorable outcomes (mRS = 0-2) were seen in 77.1%. SRS target volume was an independent predictor of treatment failure regardless of pre-SRS embolization. CONCLUSIONS: High AVM obliteration rates were achieved with judicious use of radiosurgery alone or with embolization. Embolization reduced target nidus volume by an average of 66%. SRS target volume was an independent predictor of treatment failure.