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Introduction: Optimizing patient selection and time-to-intervention will be crucial to the success of future clinical trials seeking to implement therapies and improve intracerebral hemorrhage (ICH) patient outcomes. Automated and accurate ICH and perihematomal edema (PHE) volumetry carries significant potential to strengthen trials targeting ICH and PHE expansion. Aims: The Quantification of Hematoma and Perihematomal Edema Volumes in Intracerebral Hemorrhage (QUANTUM) trial was designed with aims of (1) validating a fully automated artificial intelligence (AI) method for supratentorial, spontaneous ICH and PHE volumetry against the manual and semiautomated quantification methods and (2) establishing a model framework for the translation of AI technology through conduct of a clinical trial under the equivalence hypothesis paradigm. Methods: This trial was a prospective, randomized, clinical study with blinded outcome assessment. Six independent raters were randomized in a 1:1 ratio to ICH and PHE volumetry from non-contrast CT scans in the Virtual International Stroke Trials Archive with either the semiautomated or manual quantification method. The primary outcomes were equivalence between (1)ICH volume measurements on admission (<24h from symptom onset) for the manual versus the fully automated or the sem-automated quantification methods, and (2)PHE volume measurements on day 3 (72±12h from symptom onset) for the manual versus the fully automated or the semiautomated quantification methods. The required sample size was 126 ICH and 126 PHE measurements, based upon a significance level of 0.025 to account for the two equivalence tests. Results: The geometric mean relative discrepancies between the fully automated and the manual ICH and PHE volume measurements did not cross the pre-specified 10% equivalence margin. The geometric mean relative discrepancies between the semiautomated and the manual ICH and PHE volume measurements did cross the pre-specified 10% equivalence margin. The fully automated method (mean 10.0±2.7s/scan) was significantly faster than the manual (mean 189±199 s/scan; P <0.001) and semiautomated (mean 79±68s/scan; P <0.001) methods. Conclusions: ICH and PHE volumes quantified by AI could replace clinician measurements within a 10% error margin and with substantially greater efficiency. The semiautomated method could not replace manual measurements. This trial demonstrated feasibility of the equivalence hypothesis framework for AI validation studies.

Background The Woven EndoBridge (WEB) device represents an innovative solution for cerebral aneurysm occlusion, particularly for challenging wide-neck bifurcation aneurysms. However, factors affecting sustained occlusion remain poorly understood. We utilized machine learning to attempt to identify predictors of favorable long-term outcomes following WEB treatment. Methods In this multicenter retrospective study, we collected patient demographics, aneurysm characteristics, procedural details, and clinical outcomes. The primary endpoint was improvement in occlusion status, defined as maintained Raymond-Roy Occlusion Classification (RROC) grade 1, or improvement from grade 2 to 1, or from grade 3 to either 2 or 1 on final angiographic follow up. The dataset was split into training (75%) and validation (25%) sets. The CatBoost algorithm was selected based on performance metrics, with Shapley Additive exPlanations (SHAP) values calculated to determine feature importance. Furthermore, a multivariable binomial logistic regression model was performed to validate machine learning findings. Results Among 720 aneurysms from 36 hospitals, 84% showed improvement in occlusion at follow up. Both machine learning and multivariable logistic regression identified aneurysm height as the most consistent correlate of nonimprovement (odds ratio (OR) 0.90 per mm, p = 0.022). In the CatBoost model, the highest-ranking features by SHAP included aneurysm height, patient age, treatment acuity, ACom location, WEB-SLS device, bifurcation anatomy, aneurysm multiplicity, baseline modified Rankin Scale, access route, and partial thrombosis. Conclusions Machine-learning and regression analyses identified consistent predictors of occlusion improvement after WEB treatment, with aneurysm height most strongly linked to nonimprovement. These insights may guide patient selection and follow up. Findings require cautious interpretation and external validation in larger cohorts.

Stereotactic radiosurgery was associated with a higher obliteration rate compared with embolization in patients with eloquent brain arteriovenous malformations, whereas there was no evidence of a difference in functional outcomes or complications after adjustment.

Background: Patients with acute ischemic stroke secondary to distal and medium vessel occlusion (AIS-DMVO) and minor strokes present a challenge in determining the most appropriate emergent treatment. Factors leading to early neurological deterioration (END) in this patient population are understudied, but END is known to result in poor functional outcomes. Therefore, we aimed to investigate the factors contributing to END in minor AIS-DMVO cases. Methods: We included patients with AIS-DMVO and minor strokes from 37 sites across North America, Asia, and Europe. Minor stroke was defined as a baseline National Institutes of Health Stroke Scale (NIHSS) score of ⩽5. The primary outcome measure, END, was defined as a shift of ⩾4 points in the NIHSS score at day one after treatment compared to baseline. Univariable and multivariable logistic regression analyses were performed to identify factors associated with END. Results: Among 559 consecutive patients with DMVO and minor strokes, END was reported in 68 patients. In multivariable analysis, mechanical thrombectomy (MT) was independently associated with higher odds of END (adjusted odds ratio [aOR] 2.37, 95% CI 1.12–5.02, p = 0.02), while intravenous thrombolysis (IVT) was associated with lower odds of END (aOR 0.46, 95% CI 0.26–0.81, p = 0.008). However, the association between MT and END was no longer statistically significant in the IPTW-adjusted analysis (OR 1.65, 95% CI 0.69–3.98, p = 0.26). Hypertension and antiplatelet use at baseline were also independently associated with END. Among MT-treated patients, successful and excellent recanalization and first-pass effect were protective against END. Conclusion: MT was associated with END in patients with minor AIS-DMVO, although this association was not significant after IPTW adjustment. IVT was independently associated with reduced risk of END. These findings support careful patient selection and further study in randomized trials.

Background and objectives Arteriovenous malformations (AVMs) with perinidal aneurysms and single draining vein are associated with an elevated risk of rupture and increased procedural complexity. The role of preoperative embolization in this high-risk anatomical subset remains unclear. This study aimed to evaluate the safety and efficacy of microsurgery with preoperative embolization, compared with microsurgery alone in patients with such AVMs. Methods We conducted a multicenter retrospective analysis of an AVM registry from the MISTA (Multicenter International Study for Treatment of Brain AVMs) consortium and included AVMs with perinidal aneurysms and a single draining vein. Baseline characteristics, angiographic outcomes, functional outcomes, and complication rates were compared. Propensity score weighting (PSW) using the covariate balancing method was applied to adjust for baseline differences. Results Out of a total of 1919 patients, 65 met the inclusion criteria; 45 patients underwent preoperative embolization followed by microsurgery, and 20 underwent microsurgery alone. After adjustment, complete obliteration rates were similar between groups (OR 0.87, 95% CI 0.04 to 16.33, P=0.92), as were rates of functional independence at discharge and follow-up. Overall complication, symptomatic complication, and mortality rates did not differ significantly between groups. However, permanent complications were significantly lower in patients with preoperative embolization (OR 0.06, 95% CI 0.004 to 0.84, P=0.03). Discussion In patients with AVMs featuring perinidal aneurysms and single draining vein, preoperative embolization followed by microsurgery was associated with fewer permanent complications and no increase in adverse outcomes compared with microsurgery alone. However, given the small number of events, this finding should be interpreted cautiously.

OBJECTIVE Mechanical thrombectomy (MT) is well established for large-vessel occlusion (LVO) strokes, but its safety in distal and medium-vessel occlusions (DMVOs) requires further investigation. This study analyzed the relationship between procedural approaches, petechial hemorrhage (PetH), and clinical outcomes in DMVO thrombectomy, with particular attention to technical considerations and the complex interplay between tissue injury and hemorrhagic complications. METHODS A retrospective cohort study was conducted on DMVO stroke patients treated with MT at 37 stroke centers worldwide from 2016 to 2024. Patients were categorized based on follow-up imaging into those with or without PetH. Four logistic regression models analyzed the association of PetH with favorable functional outcomes (modified Rankin Scale score ≤ 2) at 90 days, early neurological improvement (≥ 4-point National Institutes of Health Stroke Scale score decrease at 24 hours), all-cause mortality, and independent determinants of PetH. Adjusted odds ratios (aORs), 95% confidence intervals, and p values were reported. RESULTS Of 1428 patients, 439 (30.7%) developed PetH. Factors independently associated with PetH were multiple thrombectomy passes (aOR 1.58, 95% CI 1.21–2.06; p = 0.001), IV thrombolysis (aOR 1.31, 95% CI 1.01–1.69; p = 0.04), and the combined use of a stent retriever with aspiration as the first-line method compared with aspiration alone (aOR 1.66, 95% CI 1.15–2.38; p = 0.007). Conversely, general anesthesia (aOR 0.55, 95% CI 0.40–0.77; p < 0.001), higher Alberta Stroke Program Early CT Scores (aOR 0.76, 95% CI 0.69–0.83; p < 0.001), and successful recanalization (aOR 0.56, 95% CI 0.39–0.80; p = 0.002) were significantly associated with a lower odds of PetH. PetH was associated with a decreased odds of favorable functional outcomes (aOR 0.51, 95% CI 0.36–0.73; p < 0.001), reduced early neurological improvement (aOR 0.59, 95% CI 0.44–0.79; p < 0.001), and increased all-cause mortality (aOR 1.84, 95% CI 1.23–2.76; p < 0.001). CONCLUSIONS PetH is a frequent sequela following MT in DMVO strokes and is associated with poorer outcomes, likely reflecting underlying ischemic injury rather than direct causation. Procedural factors influence PetH risk, suggesting medical treatment as first-line therapy for DMVOs, with MT reserved for refractory cases using less aggressive approaches.

Introduction Infectious intracranial aneurysms (IIAs) are rare but serious complications of systemic infections, particularly infective endocarditis. These aneurysms are prone to rupture, leading to significant morbidity and mortality. Management strategies lack consensus due to the rarity of the condition and reliance on small case series. This study examines the clinical management of IIAs using data from a large multicenter cohort. Methods A retrospective registry-based cohort study was conducted across 11 tertiary care centers in the USA between 2018 and 2023. Patients with IIAs were identified based on clinical and radiographic criteria. The primary outcome was treatment failure defined as persistence, growth, or rupture of the aneurysm. Secondary outcomes were mortality and the modified Rankin Scale (mRS) score at 90 days and 1 year. Multivariate logistic regressions were used to identify outcome predictors. Results A total of 104 patients with 166 aneurysms were included, with a median age of 43 years. Medical management was successful in 56% of cases, with failure often within 18 days of initiation. Predictors of failure included younger age, larger aneurysm size, and rupture at presentation. Surgical and endovascular interventions achieved higher success rates with better outcomes. At 90 days, 57% of patients achieved functional independence (mRS 0–2), while the mortality rate was 24%. Conclusion This study highlights the limitations of medical management for IIAs and underscores the need for early surgical or endovascular intervention in high-risk patients. Outcome predictors aid clinical decision-making, optimizing patient management. Further research is needed to standardize management guidelines for IIAs.

Background The Woven EndoBridge (WEB) device is a prevalent treatment for intracranial aneurysms. While many studies have assessed the obliteration rate post-WEB embolization, few have focused on long-term outcomes in partially thrombosed aneurysms. Objective To assess whether partially thrombosed aneurysms are at higher risk of recurrence or retreatment following WEB embolization compared with non-thrombosed aneurysms. Methods We evaluated data from 22 academic institutions, focusing on previously untreated cerebral aneurysms treated with the WEB device. Logistic regression was utilized to analyze factors predicting long-term aneurysm obliteration and retreatment necessity. Results Among 1303 patients, 26 presented with a partially thrombosed aneurysm. In the partially thrombosed group, the mean aneurysm maximal diameter was 10.7±4 mm with a neck ratio of 1.99±1.19 mm, larger than in the control group where the mean aneurysm maximal diameter was 6.81±2.37 mm with a neck ratio of 1.64±0.51 mm (P<0.001 for both maximal diameter and neck ratio). At the final follow-up, partially thrombosed aneurysms treated by the WEB device had a 38.5% retreatment rate, compared with 7.0% for non-thrombosed aneurysms (P<0.001). Among partially thrombosed aneurysms, the Raymond-Roy type IIIa/b occlusion rate was higher (38.5% vs 9.9%, P<0.001). On multivariate analysis, partially thrombosed aneurysms compared with non-thrombosed aneurysms had an increased rate of retreatment (OR 3.64, 95% CI 1.28 to 10.1). Conclusion Partially thrombosed aneurysms are associated with a poorer occlusion rate and a higher rate of retreatment following WEB embolization. For partially thrombosed aneurysms, the WEB device appears suboptimal as a first-line treatment, and therefore alternative techniques should be prioritized.

Background Flow-diverter stents (FDS) have become the standard of care for a wide range of intracranial aneurysms, but their efficacy/safety in the context of recurrent/recanalized aneurysms following stent-assisted coiling (SAC) is not well established. We evaluate the outcomes of FDS retreatment in a large multicenter cohort. Methods We retrospectively analyzed data from 118 patients across 22 institutions who underwent FDS retreatment for recurrent/persistent aneurysms after SAC (2008–22). The primary outcome was angiographic occlusion status at last follow-up, categorized as complete (100%), near-complete (90–99%), or incomplete (<90%) occlusion. Secondary outcomes included procedural complications and clinical outcomes measured by the modified Rankin Scale (mRS). Results A total of 118 patients (median age 57, 74.6% female) with median follow-up of 15.3 months were identified. Complete occlusion was achieved in 62.5% and near-complete occlusion in 25%. FDS deployment within the pre-existing stent was successful in 98.3% of cases. Major complications occurred in 3.4% of cases, including postoperative aneurysmal rupture with resultant mortality (1.6%) and thromboembolic events with long-term disability (1.6%). Favorable clinical outcomes (mRS 0–2) were observed in 95.1% of patients. Wider aneurysm neck diameter was a significant predictor of incomplete occlusion (adjusted OR (aOR) 1.23 per mm, P=0.044), with male sex trending towards association with non-occlusion (aOR 3.2, P=0.07), while baseline hypertension was associated with complete occlusion (aOR 0.32, P=0.048). Conclusions FDS treatment for recurrent/residual aneurysms after SAC represents a viable treatment option for these challenging cases with acceptable safety and reasonable occlusion rates, although lower than de novo FDS occlusion rates.

Background Mechanical thrombectomy (MT) is established as an effective treatment for large vessel occlusion strokes, but its efficacy and safety for medium vessel occlusions (MeVOs) remain less clear. This study examines the impact of periprocedural embolization to a new vascular territory (ENT) on clinical outcomes in patients with MeVO stroke treated with MT. Methods A multicenter, retrospective analysis was conducted using the MAD-MT (Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy) registry, including 2122 patients with MeVO stroke w­ho underwent MT between September 2017 and July 2023. ENT was defined as filling defects in previously unaffected territories, excluding embolization near the original occlusion, observed on final angiographic runs after retrieval of the primary thrombus. The associations between ENT, procedural variables, and 90-day clinical outcomes were evaluated, including functional independence (modified Rankin Scale (mRS) scores of 0–2), excellent outcomes (mRS 0–1), mortality, and hemorrhagic complications. Results ENT occurred in 2.9% (63/2122) of patients. Longer onset-to-arterial puncture time (adjusted OR 1.03; 95% CI 1.01 to 1.05; P=0.002) and a greater number of passes (adjusted OR 1.15; 95% CI 1.01 to 1.32; P=0.032) were associated with increased ENT risk, while excellent recanalization (thrombolysis in cerebral infarction (TICI) scale score 2c–3) was associated with reduced ENT risk (adjusted OR 0.41; 95% CI 0.23 to 0.72; P=0.002). ENT was not associated with poorer functional independence, mortality, or hemorrhagic complications. Conclusions ENT during MT for MeVO stroke occurs infrequently and does not significantly affect the clinical outcomes. These findings suggest ENT risk should not deter clinicians from performing MT in patients with MeVO. Further prospective studies are needed to validate these results.