Deep venous drainage (DVD) is considered a negative prognostic factor in AVM surgery, yet its effect on postoperative functional decline remains incompletely defined. This study evaluates whether DVD predicts worsened functional status after surgical resection of Spetzler-Martin Grade II-III AVMs. This retrospective multicenter study analyzed 129 patients with Spetzler-Martin Grade II-III AVMs across nine centers in North America and Europe who underwent primary surgical resection. We excluded cases with prior endovascular or stereotactic interventions. The primary outcome measured was poor functional status, defined as modified Rankin Scale (mRS) score 3–6 at last follow up. Among 129 patients with Spetzler-Martin Grade II-III AVMs, 38 (29.5

BACKGROUND AND OBJECTIVES:Moyamoya disease (MMD) is a progressive occlusive arteriopathy marked by stenosis of the major cerebral arteries and the development of fragile basal collaterals. Although ischemic and hemorrhagic phenotypes of MMD are well described, comparative evidence evaluating differences in surgical safety and long-term treatment response between these subgroups remains limited. This study aimed to compare perioperative complications and long-term stroke risk after revascularization surgery in patients with ischemic-type vs hemorrhagic-type MMD. METHODS:We conducted a multicenter retrospective cohort study across 13 North American academic centers (2008-2022), including 485 patients with 502 revascularized hemispheres for angiographically confirmed MMD. Hemispheres were stratified by presenting phenotype. Primary outcomes were overall postoperative complications and long-term stroke events. Propensity score matching (2:1) and multivariable logistic regression were used. A sensitivity analysis including only hemispheres with ≥2 years of follow-up was performed. RESULTS:Of 502 hemispheres, 423 (84%) presented with ischemia and 79 (16%) with hemorrhage. Before and after matching, ischemic-onset MMD demonstrated significantly higher overall postoperative complication rates (post-match: 10% vs 2.6%, P = .043). Stroke patterns at long-term follow-up reflected initial presentation: ischemic-onset hemispheres experienced predominantly ischemic recurrences, whereas hemorrhagic-onset hemispheres showed higher rates of hemorrhagic or mixed-pattern strokes (P < .001). In the sensitivity cohort (≥2-year follow-up; mean 78.5 months), hemorrhagic presentation was independently associated with an 8-fold higher risk of long-term stroke, as compared with ischemic presentation (adjusted odds ratio 8.23; 95% CI 1.84-36.8; P = .006). Stroke risk did not differ significantly between hemorrhage subtypes. CONCLUSION:Ischemic and hemorrhagic MMD represent distinct clinical phenotypes with meaningful differences in safety and long-term response to surgical revascularization. Ischemic-type MMD is more prone to postoperative complications, whereas hemorrhagic-type MMD was associated with a substantially elevated long-term stroke risk. These findings underscore the need to consider MMD phenotypes as separate entities when counseling patients, choosing treatment strategies, and initiating long-term surveillance.

Moyamoya angiopathy (MMA) lacks stage-specific comparative evidence for surgical strategy. Because many studies mix Suzuki grades, potential technique effects may be obscured. We compared direct revascularization (DR) with indirect revascularization (IR) in a stage-restricted cohort (Suzuki I-III), using propensity score weighting (PSW). We conducted a multicenter retrospective cohort study across 13 academic centers. Adults with confirmed MMA (Suzuki I-III) who underwent DR or IR were included. Patients < 16 years and combined procedures were excluded. Outcomes were symptomatic stroke, overall perioperative stroke, intraoperative complications, discharge NIHSS/mRS, length of stay, and follow-up stroke. PSW used Covariate Balancing Propensity Scores (CBPS) with absolute standardized mean difference (ASMD) diagnostics. Group differences were modeled with logistic/linear regression, and stroke-free survival was compared by Kaplan-Meier/log-rank. We analyzed 208 hemispheres (IR = 104; DR = 104). Baseline demographics and comorbidities were similar. Unadjusted analyses showed no significant differences in overall perioperative stroke (10.5

Background Evidence on thrombectomy outcomes for posterior circulation tandem occlusions (TOs) is mostly from small single-center series. Purpose To evaluate thrombectomy outcomes in posterior circulation TOs. Materials and Methods Data from consecutive patients from 15 North American centers (February 2016 to October 2023) who underwent thrombectomy for posterior circulation TOs-defined as intracranial vertebral artery, basilar artery, or posterior cerebral artery occlusion with concurrent proximal extra- or intracranial vertebral artery stenosis or occlusion-were retrospectively analyzed. Baseline clinical, imaging, and procedural variables were summarized. Primary and clinical outcomes included successful reperfusion (modified Thrombolysis in Cerebral Infarction [mTICI] score ≥ 2b), safety outcomes (symptomatic intracranial hemorrhage [sICH] and procedure-related complications), and 90-day functional outcome (modified Rankin Scale [mRS] score). Univariable and multivariable logistic regression was used to identify factors associated with favorable outcomes. Results Among 123 patients (median age, 63 years [IQR, 55-72 years]; 77 male patients), median National Institutes of Health Stroke Scale (NIHSS) score was 17 (IQR, 9-28). Intravenous thrombolytics were administered in 37 of 123 (30.1%) patients, and 97 of 123 (78.9%) underwent general anesthesia. Combined stent retriever and aspiration was the most common distal thrombectomy technique (45 of 123 [36.6%]), then aspiration (40 of 123 [32.5%]). Rescue stenting was required in 48 of 123 (39.0%) patients, more for proximal than distal lesions (44 of 123 [35.8%] vs nine of 123 [7.3%]; P = .01). Median puncture-to-reperfusion time (ie, from groin puncture to mTICI score ≥ 2b) was 50 minutes (IQR, 31-91 minutes). Successful reperfusion occurred in 108 of 122 (88.5%) patients, and sICH occurred in 11 of 123 (8.9%). At 90 days, 55 of 117 (47.0%) patients had a favorable outcome (mRS score of 0-3), and 37 of 117 (31.6%) had died. Distal-first strategy (ie, distal lesion thrombectomy first) was associated with shorter puncture-to-reperfusion time (P = .02) and lower incidence of sICH (P = .04); "dirty road" technique was associated with rescue stenting (P = .04). In multivariable analysis, hyperglycemia (P = .03), hypertension (P = .046), higher baseline mRS score (P = .008), and higher presentation NIHSS score (P = .03) predicted unfavorable functional outcome (mRS score of 4-6), whereas prestroke antithrombotic use (P = .006), monitored anesthesia care (P = .03), successful reperfusion (P = .02), and distal-first strategy (P = .01) predicted favorable functional outcome. Conclusion Thrombectomy for posterior circulation TOs was feasible and effective, with favorable outcomes associated with the distal-first strategy. © RSNA, 2026 Supplemental material is available for this article.

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 AND OBJECTIVES:Middle cerebral artery bifurcation (MCAb) aneurysms have primarily been managed through microsurgical clipping (MC). However, the effectiveness and safety of evolving neurointerventional methods warrant a comprehensive examination and comparison with MC. We investigated patient and MCAb aneurysm characteristics and compared imaging outcomes for MC, simple coiling (SC), stent-assisted coiling (SAC), flow-diverting stent placement (FD), and endosaccular flow disruption. METHODS:A retrospective review of MCAb aneurysm databases from 10 US centers was conducted to identify patients treated between January 2008 and January 2023. Primary analyses compared data across all 5 treatment modalities individually and for MC vs endovascular modalities. Secondary analyses consisted of pairwise comparisons between these modalities for saccular MCAb aneurysms. RESULTS:We analyzed data for 1060 patients with 1060 MCAb aneurysms (MC = 722, SC = 134, SAC = 106, FD = 34, and endosaccular flow disruption = 64). The treatment groups differed significantly in mean patient age (P < .001), sex distribution (P = .044), and baseline mRS score (P < .001). No treatment preference was noted for recurrent aneurysms. Ruptured aneurysms were most common in SC and least common in FD (P < .001). Wide-necked aneurysms were most frequent in FD (P < .001). Intraoperative complications were similar, although SAC had more vasospasm (P = .006) and device-related complications (P = .010), and FD had more thromboembolic events (P = .047). Postoperative complications varied (P = .007): MC had more vasospasm (P = .043). Follow-up durations varied significantly (P < .001). Follow-up complications differed (P = .012): FD had more transient ischemic attacks (P = .042) and ischemic strokes (P < .001); SC had more aneurysmal rehemorrhage (P = .027). Immediate and final aneurysmal occlusion was considerably better with MC (P < .001), followed closely by SAC. CONCLUSION:MC remained the preferred modality for treating both unruptured and ruptured MCAb aneurysms, demonstrating superior immediate and final angiographic occlusion rates with minimal intraoperative and postoperative complications. SAC showed similar safety but was technically more challenging, FD had higher ischemic event rates, and SC had more delayed reruptures.

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.

INTRODUCTION:Asymptomatic moyamoya angiopathy (MMA) is increasingly detected through noninvasive imaging; however, its optimal management remains controversial. This multicenter retrospective cohort study compared outcomes in asymptomatic versus symptomatic MMA patients undergoing surgical revascularization. PATIENTS AND METHODS:A total of 475 patients treated with bypass surgery across multiple academic centers were included, with 56 (11.8%) classified as asymptomatic and 419 (88.2%) as symptomatic. Baseline demographics, surgical characteristics, and outcomes-including perioperative stroke, intraoperative complications, and follow-up stroke events-were collected. Asymptomatic MMA was defined as the absence of any prior ischemic or hemorrhagic stroke, seizures, or other neurological symptoms at the time of diagnosis. Both unadjusted analyses and propensity score weighting using inverse probability of treatment weighting (IPTW) were performed to adjust for potential confounders. RESULTS:In the unadjusted analysis, asymptomatic patients had significantly lower rates of all perioperative strokes (1.7% vs 11.4%; p = 0.05) and intraoperative complications (1.7% vs 11.2%; p = 0.05) compared to symptomatic patients. Additionally, follow-up stroke rates were lower in the asymptomatic group (1.7% vs 11.2%; p = 0.05). After IPTW adjustment, the reduction in intraoperative complications (OR: 0.08, 95% CI: 0.01-0.64; p = 0.01) and follow-up stroke rates (OR: 0.12, 95% CI: 0.01-0.91; p = 0.04) persisted, while differences in overall perioperative stroke were not statistically significant. CONCLUSION:Bypass surgery in selected asymptomatic MMA patients is associated with reduced intraoperative complications, and fewer follow-up stroke rates. These findings support the careful consideration of surgical intervention in asymptomatic patients, emphasizing the importance of patient selection for optimal outcomes.

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.

Data on the use of Woven EndoBridge (WEB) devices in the treatment of narrow-neck intracranial aneurysms (NNA) are limited. We compared the efficacy and safety of single-layer (SL) and single-layer spherical (SLS) WEB devices in treating NNA. We conducted a multicenter retrospective analysis of adult patients with NNA (neck ≤ 4 mm and width-to-neck ratio ≥ 2) treated with SL or SLS WEB devices between January 2011 and December 2022. Patients with fusiform or blister aneurysms, adjunctive treatments, or devices other than SL or SLS were excluded. Propensity score matching was used to adjust for confounding variables. Outcomes included procedural complications, angiographic occlusion rates using the Raymond Roy classification, major device compaction, need for retreatment, and functional outcomes assessed by the modified Rankin Scale (mRS). After matching, resulting in 101 patients in each group, baseline characteristics were well-balanced. Thromboembolic complications occurred in 2.0

BACKGROUND:Moyamoya syndrome (MMS) associated with sickle cell disease (SCD) is a severe vasculopathy that significantly increases stroke risk. While cerebral revascularization is increasingly considered in this population, concerns about perioperative safety and long-term outcomes have limited its use in clinical practice. METHODS:We conducted a multicenter, retrospective cohort study of 553 patients with MMS who underwent surgical revascularization across 13 centers. Patients were grouped by SCD status (SCD-MMS vs. moyamoya disease (MMD)). Primary outcomes included perioperative stroke, perioperative complications, and functional status at discharge. Secondary outcomes included length of stay, and follow-up stroke. RESULTS:Of 553 patients, 32 (5.8%) had SCD. There were no significant differences in overall perioperative stroke (OR 1.05, 95% CI 0.19 to 5.54), symptomatic perioperative stroke (OR 0.94, 95% CI 0.09 to 8.94), perioperative complications (OR 1.66, 95% CI 0.47 to 5.86), or follow-up stroke (OR 0.88, 95% CI 0.17 to 4.55). Functional outcomes at discharge were similarly favorable in both groups (mRS 0-1: OR 0.84, 95% CI 0.29 to 2.40). SCD was associated with a longer hospital stay (beta 2.78 days, 95% CI 0.60 to 4.96). CONCLUSION:Surgical revascularization for MMS in patients with SCD does not confer additional procedural risk and yields outcomes comparable to those of patients without SCD. These findings support the role of bypass surgery as a viable treatment option in this high-risk population.

Sex-related differences in outcomes after mechanical thrombectomy (MT) for distal medium vessel occlusion (DMVO) stroke remain uncertain. While unadjusted differences have been reported in stroke populations, it is unclear whether biological sex independently influences outcomes after accounting for major prognostic factors. We performed a retrospective, multicenter analysis of the MAD-MT registry. Patients with acute DMVO who underwent MT were included. Propensity score matching (PSM) was employed. The primary outcome was functional independence (modified Rankin Scale [mRS] score 0–2) at 90 days. Secondary outcomes included excellent outcome (mRS 0–1), day 1 NIHSS shift, and reperfusion success. Safety outcomes included mortality and symptomatic intracerebral hemorrhage. Before matching, 1147 females and 1062 males were included. After 1:1 PSM (748 patients in each group), the groups were balanced in baseline characteristics. The median age was 75 years in both groups. At 90 days, 51

Optimal treatment for acute ischemic stroke due to distal medium-vessel occlusion (DMVO) in the middle cerebral artery (MCA) remains uncertain. While mechanical thrombectomy (MT) may pose higher risks in DMVO, intra-arterial thrombolysis (IAT)—with or without intravenous thrombolysis (IVT)—could be a safer alternative. To compare functional outcomes and safety profiles of IAT versus MT in acute ischemic stroke caused by MCA DMVO (M2–M4 segments). We performed a retrospective, propensity score-matched study across 37 centers (Asia, Europe, North America) using the MAD-MT registry. Patients with MCA DMVO (M2–M4) treated with IAT or MT (with/without IVT) were included. Propensity score matching adjusted for confounders. The primary outcome was excellent functional outcome (modified Rankin Scale [mRS] 0–1 at 90 days). After matching, 184 patients were analyzed (19 IAT, 165 MT). Baseline characteristics were balanced. At 90 days, excellent functional outcomes occurred in 38

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.

BACKGROUND:Cerebral arteriovenous malformations (AVMs) are complex vascular lesions that pose a risk for hemorrhagic stroke. The number of draining veins has recently emerged as a significant predictor of rupture risk. This multicenter study aimed to evaluate the outcomes in adult AVM patients with single versus multiple draining veins. METHODS:We conducted a retrospective analysis of 735 AVM patients from the Multicenter International Study for Treatment of Brain AVMs (MISTA) database. Patients were categorized into single draining vein (n = 430) and multiple draining veins (n = 305) groups. Logistic and linear regression models were used to assess outcomes, adjusting for baseline characteristics, including age, rupture status, Spetzler-Martin grade, and other relevant factors. RESULTS:After adjustment, no significant differences were observed in complete AVM obliteration at last follow-up between the multiple and single draining veins groups (OR: 1.1; 95 % CI: 0.72-1.93, p = 0.49) after any treatment type. Good functional outcomes at last follow-up (mRS 0-2) were similar between the two groups (OR: 1.00; 95 % CI: 0.48-2.09, p = 0.98), as were retreatment rates (OR: 1.68; 95 % CI: 0.74-3.83, p = 0.21). Ruptured AVMs were more common in the single draining vein group (52.0 % vs. 35.4 %, p < 0.001). Patients in the multiple draining vein group had lower odds of hemorrhagic complications compared to the single vein group (OR: 0.38; 95 % CI: 0.14-1.02, p = 0.05). CONCLUSION:Single draining vein AVMs were more likely to present with rupture, but no significant differences in obliteration rates, functional outcomes, or retreatment rates were found between the groups after adjustment. These findings suggest that while venous drainage patterns may influence initial presentation, they do not appear to affect overall treatment success or patient prognosis after any treatment type. Further studies are needed to confirm.

BackgroundEndovascular therapy (EVT) for stroke due to distal or medium vessel occlusion (DMVO) is safe. Due to the distinct anatomical characteristics of DMVOs, further evaluation of EVT is crucial to determine which devices may yield better outcomes.MethodsA retrospective analysis of adults with DMVO treated in 37 centers (11 countries) was queried. The primary outcome of favorable shift in 90-day modified Rankin Scale (mRS) was compared between patients treated with Trevo versus other devices on first pass using 1:1 propensity score matching (PSM) with multivariable adjustment. Secondary outcomes included the number of pass attempts, final thrombolysis in cerebral infarction (TICI) score 2b-3, symptomatic intracranial hemorrhage (sICH), improvement in National Institutes of Health Stroke Scale (NIHSS) at 24h, and 90-day mortality.ResultsOf the 1115 included patients, 264 (24%) were treated with Trevo (PSM cohort of 261 per group). Trevo use was not associated with a favorable 90-day mRS shift (proportional odds ratio [OR] 1.10, 95% confidence interval [CI] 0.80-1.51). Trevo was associated with fewer passes (adjusted β=-0.25, 95% CI -0.48 - -0.03), higher odds of TICI 2b-3 (adjusted OR 1.97, 95% CI 1.11-3.49), and a greater 24h NIHSS improvement (adjusted β= -1.74, 95% CI -3.11 - -0.36), with no difference in sICH or mortality (p>0.05). Results were similar in sensitivity analyses.ConclusionsWe observed no safety concerns with Trevo as compared to other EVT devices for DMVO recanalization. There was a signal of better technical efficacy and early clinical improvement.