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The safety and efficacy of coronavirus disease 2019 (COVID-19) vaccination in patients diagnosed with Moyamoya disease (MMD) have not been established. Using National Health Insurance Service data, this study analyzed the occurrence of stroke-related events and mortality following COVID-19 vaccination among patients diagnosed with MMD from 2008 to 2020. Among 10,297 MMD patients, 296 (2.9%) experienced events and 175 (1.7%) died in 2021. Significant risk factors for events included ages 50-59 (Odds Ratio [OR] 3.29; P = 0.022) and 60 or above (OR 5.20; P = 0.001) (reference group: age in 20s), low BMI (OR 2.00; P = 0.011), previous stroke (OR 1.96; P < 0.001), and COVID-19 infection (OR 2.28; P = 0.034). Female (OR 0.64 [95% CI 0.50-0.82]; p = 0.011), revascularization surgery (RS) (OR 0.38 [95% CI 0.21-0.70]; p < 0.001), and vaccination (OR 0.17 [95% CI 0.13-0.22]; p < 0.001) were associated with reduced odds of stroke-related events. For mortality, significant risks were age over 60 (OR 7.09; P = 0.008), low BMI (OR 3.87; P = 0.001), and prior stroke (OR 1.74; p = 0.004), while being female, RS (OR 0.41; P = 0.022), and vaccination (OR 0.12; P < 0.001) were associated with a lower frequency of mortality. mRNA vaccines were associated with a significantly lower incidence of events, mortality, and COVID-19 infections compared to vector vaccines. COVID-19 vaccination is linked to reduced stroke-related events and mortality in MMD patients, with mRNA vaccines showing a significantly lower incidence compared to vector vaccines. COVID-19 infection raises the risk of events, underscoring the benefit of vaccination., (© 2024. The Author(s).)

Background and Purpose: Swelling of the salivary glands, known as contrast-induced sialadenitis (CIS), is an adverse reaction to iodide contrast agents. However, the incidence and risk factors of CIS after therapeutic neuroendovascular procedures have not yet been established., Materials and Methods: Demographic and procedural factors that may influence the development of CIS were retrospectively analyzed to identify the incidence and risk factors of this condition. A total of 780 patients who underwent therapeutic neuroendovascular procedures between January 1, 2022 and December 31, 2022 were investigated. The risk factors affecting CIS were analyzed using multivariate logistic regression, and the quantitative degree of association between the volume of contrast administered and occurrence of CIS was determined using the receiver operating characteristic (ROC) curve., Results: The incidence of CIS after therapeutic neuroendovascular procedures was 4.2%. Multivariate logistic regression analysis showed that female sex (odds ratio [OR] = 4.420, 95% confidence interval [CI]: 1.377-14.190, p = 0.013), volume of contrast administered (OR = 1.007, 95% CI: 1.003-1.101, p < 0.001), and guiding catheter tip located within the external carotid artery (ECA) (OR = 8.701, 95% CI: 3.459-21.885, p < 0.001) were independently associated with CIS occurrence after therapeutic neuroendovascular procedures. The volume of contrast administered had an area under the ROC curve of 0.723 (95% CI:0.635-0.810; p < 0.001), and the optimal cut-off value of the volume of contrast administered was 205 cc (sensitivity: 0.49, specificity: 0.87)., Conclusions: We observed CIS in 4.2% of our patients undergoing therapeutic neuroendovascular procedures. This represents a higher incidence than previously reported. Female sex, volume of contrast administered, and guiding catheter tip located within the ECA are associated with CIS incidence., Abbreviations: AUC = area under the ROC curve; BMI = body mass index; CIS = contrast-induced sialadenitis; ECA = external cerebral artery; GFR = glomerular filtration rate; ROC = receiver operating characteristic., Competing Interests: The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper., (© 2024 by American Journal of Neuroradiology.)

Background: To analyze the outcomes of clipping and coiling for ruptured intracranial aneurysms (RIAs) based on data from the National Health Insurance Service in South Korea, with a focus on variations according to region and hospital size., Methods: This study analyzed the one-year mortality rates for patients with RIAs who underwent clipping or coiling in 2018. Coiling was further categorized into non-stent assisted coiling (NSAC) and stent assisted coiling (SAC). Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs), or semi-general hospitals (sGHs) based on size. South Korea's administrative districts were divided into 15 regions for analysis., Results: In 2018, there were 2,194 (33.1%) clipping procedures (TRGH, 985; GH, 827; sGH, 382) and 4,431 (66.9%) coiling procedures (TRGH, 1,642; GH, 2076; sGH, 713) performed for RIAs treatment. Among hospitals performing more than 20 treatments, the one-year mortality rates following clipping or coiling were 11.2% and 16.0%, respectively, with no significant difference observed. However, there was a significant difference in one-year mortality between NSAC and SAC (14.3% vs. 19.5%, P = 0.034), with clipping also showing significantly lower mortality compared to SAC ( P = 0.019). No significant differences in other treatment modalities were observed according to hospital size, but clipping at TRGHs had significantly lower mortality than at GHs ( P = 0.042). While no significant correlation was found between the number of treatments and outcomes at GHs, at TRGHs, a higher volume of clipping procedures was significantly associated with lower total mortality ( P = 0.023) and mortality after clipping ( P = 0.022)., Conclusion: Using Korea NHIS data, mortality rates for RIAs showed no significant variation by hospital size due to coiling's prevalence. However, differences in clipping outcomes by hospital size and volume in TRGH highlight the need for national efforts to improve clipping skills and standardization. Additionally, the higher mortality rate with SAC emphasizes the importance of precise indications for its application., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2024 The Korean Academy of Medical Sciences.)

Objective: Stents have been widely used for coil embolization for intracranial aneurysms. Few studies have analyzed the risk factors of recanalization through long-term follow-up observation of only stent-assisted coiling. We analyzed the risk factors for recanalization through long-term observations., Methods: A total number of 399 unruptured aneurysms treated by stent-assisted coil embolization between 2003 and 2016 in a single institution were analyzed for determining the factors associated with recanalization including the patient characteristics, aneurysms, and procedural variables. All patients underwent angiographic follow-up with digital subtraction angiography or magnetic resonance angiography at 24 months or more following the procedure., Results: Recanalization occurred in 8%. The mean time for the recanalization was 21.1 ± 14.0 months (range, 5-51 months). The receiver operating characteristic curve analysis indicated areas under the curve for a maximum aneurysm size of 0.773 (cut-off, 6.415 mm). Multivariate analysis revealed that the maximum aneurysm size and parent artery curvature at which the aneurysm developed were significantly associated with recanalization. In parent artery curvature, the bifurcation group (OR, 9.02; 95% CI, 2.53-32.13; p  = 0.001) and the convex group (OR, 3.68; 95% CI, 1.17-11.50; p  = 0.025) were independent predictors of recanalization compared with the straight group., Conclusion: The maximum aneurysm size and parent artery curvature are risk factors associated with recanalization in stent-assisted coil embolization., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Won, Kim, Ban and Kwon.)

Objective: The aim of this study was to identify predictive factors of postoperative cerebral infarction (PostCI) following combined bypass (CB) surgery in adult patients with moyamoya disease (MMD) using quantitative parameters from the rapid processing of perfusion and diffusion (RAPID) perfusion CT (PCT) software., Methods: The authors retrospectively reviewed 276 total hemispheres in patients with MMD who underwent CB. Preoperative volumes of time-to-maximum (Tmax) > 4 sec and > 6 sec were obtained from the RAPID analysis of PCT. These quantitative parameters, along with other clinical and angiographic factors, were statistically analyzed to determine the significant predictors for PostCI following CB., Results: PostCI occurred in 17 hemispheres (6.16%). PCA involvement (p = 0.016), and the volume of Tmax > 6 sec (p < 0.001) and Tmax > 4 sec (p < 0.001), were identified as variables related to PostCI in the univariable analysis. In the multivariable analysis, the volume of Tmax > 6 sec (OR 1.013, 95% confidence interval 1.007-1.019, p < 0.001) was determined to be an independent predictive factor significantly associated with PostCI after CB in adult patients with MMD. In the receiver operating characteristic (ROC) curve, the cutoff value of the preoperative volume of Tmax > 6 sec was determined to be 59.5 ml (sensitivity 82.4%, specificity 71.9%, area under the ROC curve 0.811)., Conclusions: For adult patients with MMD and a large volume of Tmax > 6 sec over 59.5 ml, more caution is required when deciding to undergo bypass surgery and in postoperative management.

Background: There have been few reports on the preventative value of intensive blood pressure (BP) management for stroke since the American College of Cardiology/American Heart Association (ACC/AHA) announced the new criteria for hypertension (HTN) in 2017. This study aimed to identify optimal BP for prevention of stroke in healthy adults under 65 years., Methods: We conducted a 10-year observational study on the risk of stroke, subclassified as hemorrhagic stroke (HS) or ischemic stroke (IS), according to BP categories (low-normal BP, high-normal BP, elevated BP, stage 1 HTN, and stage 2 HTN) using the National Health Insurance Service Database., Results: In 2008, a health checkup was conducted for a total of 8,327,751 participants, and 949,551 of them enrolled in this study. The risk of HS increased from stage 2 HTN (adjusted hazard ratio [AHR], 3.036 [95 % confidence interval [CI], 2.159-4.252]) in men to stage 1 HTN (AHR, 2.972; 95 % CI, 2.256-3.897) in women. The risk of IS increased in both men (AHR, 1.404 [95 % CI, 1.164-1.693]) and women (AHR, 2.012 [95 % CI, 1.603-2.526]) with stage 1 HTN. The overall risk of stroke increased in men (AHR, 1.386; [95 % CI, 1.180-1.629]) and women (AHR, 2.363 [95 % CI, 1.973-2.830]) with stage 1 HTN., Conclusion: This study underscores the importance of maintaining BP below Stage 1 HTN to prevent stroke in healthy adults aged below 65 years. These findings highlight the significance of the new HTN guidelines established by the ACC/AHA in 2017., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: To analyze the relationship between in-stent restenosis (ISR) following carotid artery stenting (CAS) and platelet clopidogrel reactivity confirmed by the P2Y12 reaction unit (PRU) and inhibition rate (IR)., Methods: We retrospectively analyzed 171 patients who underwent CAS with extracranial carotid stenosis from January 2016 to December 2019. Dual antiplatelet therapy with 100 mg aspirin and 75 mg clopidogrel was started ≥5 days before CAS. Clopidogrel resistance was measured with the PRU and IR the day before CAS. The ISR degree was classified into R1, R2, and R3 (moderate to severe luminal stenosis of ≥50% or occlusion) by carotid CT angiography after 24-30 months. The degree of quantitative association between platelet reactivity and ISR R3 was determined by the receiver operating characteristic curve method. The optimal cut-off values of PRU and IR were derived using the maximum Youden index., Results: There were 33 R3 degrees of ISR (19.3%) and nine ipsilateral ischemic strokes (5.3%). The PRU and IR were different between R1+R2 degrees (176.4±50.1, 27.5±18.7%) and R3 degree (247.5±55.0, 10.3±13.4%) (P<0.001). The areas under the curves of PRU and IR were 0.841 and 0.781, and the optimal cut-off values were 220.0 and 14.5%, respectively. Multivariate logistic regression analysis showed that PRU ≥220 and IR ≤14.5% were significant predictive factors for ISR R3 (P<0.001 and P=0.017, respectively). ISR R3 was independently associated with ipsilateral ischemic stroke after CAS (P=0.012)., Conclusions: High PRU (≥220) and low IR (≤14.5%) are related to ISR R3 following CAS, which may cause ipsilateral ischemic stroke., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To analyze the outcomes of coil embolization (CE) for unruptured intracranial aneurysm (UIA) according to region and hospital size based on National Health Insurance Service data in South Korea., Methods: The incidence of complications, including intracranial hemorrhage (ICRH) and cerebral infarction (CI), occurring within 3 months and the 1-year mortality rates in UIA patients who underwent CE in 2018 were analyzed. Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs) or semigeneral hospitals (sGHs) according to their size, and the administrative districts of South Korea were divided into 15 regions., Results: In 2018, 8425 (TRGHs, 4438; GHs, 3617; sGHs, 370) CEs were performed for UIAs. Complications occurred in 5.69% of patients seen at TRGHs, 13.48% at GHs, and 20.45% at sGHs. The complication rate in TRGHs was significantly lower than that in GHs (p=0.039) or sGHs (p=0.005), and that in GHs was significantly lower than that in sGHs (p=0.030). The mortality rates in TRGHs, GHs, and sGHs were 0.81%, 2.16%, and 3.92%, respectively, with no significant difference. Despite no significant difference in the mortality rates, the complication rate significantly increased as the number of CE procedures per hospital decreased (p=0.001; rho=-0.635). Among the hospitals where more than 30 CEs were performed for UIAs, the incidence of CIs (p=0.096, rho=-0.205) and the mortality rates (3 months, p=0.048, rho=-0.243; 1 year, p=0.009, rho=-0.315) significantly decreased as the number of CEs that were performed increased and no significant difference in the incidence of post-CE ICRH was observed., Conclusion: The complication rate in patients who underwent CE for UIA increased as the hospital size and physicians' experience in conducting CEs decreased. We recommend nationwide quality control policies CEs for UIAs.

Background: There are few reports on the preventative value of intensive blood pressure (BP) management for stroke, especially hemorrhagic stroke (HS), after new criteria for hypertension (HTN) were announced by the American College of Cardiology/American Heart Association in 2017., Aims: This study aimed to identify the optimal BP for the primary prevention of HS in a healthy population aged between 20 and 65 years., Methods: We conducted a 10-year observational study on the risk of HS, subclassified as intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) according to BP categories (e.g., low normal BP, high normal BP, elevated BP, stage 1 HTN, and stage 2 HTN) using the National Health Insurance Service Database., Results: Out of 8,327,751 participants who underwent a health checkup in 2008, 949,550 were included in this study and observed from 2009 to 2018. The risk of ICH was significantly increased in men with stage 2 HTN {adjusted hazard ratio [aHR] 2.002 [95% confidence interval (CI) 1.203-3.332]} and in women with stage 1 HTN [aHR 2.021 (95% CI, 1.251-3.263)]. The risk of SAH was significantly increased in both men [aHR 1.637 (95% CI, 1.066-2.514)] and women [aHR 4.217 (95% CI, 2.648-6.715)] with stage 1 HTN. Additionally, the risk of HS was significantly increased in men with stage 2 HTN [aHR 3.034 (95% CI, 2.161-4.260)] and in women with stage 1 HTN [aHR 2.976 (95% CI, 2.222-3.986)]., Conclusion: To prevent primary HS, including ICH and SAH, BP management is recommended for adults under the age of 65 years with stage 1 HTN., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Shim, Park, Lee, Kim, Kim, Ban, Bang, Kwon, Oh and Lee.)

Abstract: BACKGROUND: Patients with unruptured intracranial aneurysms (UIAs) treated by coil embolization may experience illness uncertainty despite successful treatment. This study aimed to investigate illness uncertainty in patients with UIAs treated by coil embolization and to identify the factors affecting illness uncertainty. METHODS: This cross-sectional study involved data collected from 267 patients with UIAs who received coil embolization within 2 years at a tertiary hospital in South Korea. The data were collected through structured questionnaires and the patients' medical records. The questionnaires included information on sociodemographic characteristics, the Hospital Anxiety and Depression Scale, the Multidimensional Scale of Perceived Social Support, and Mishel Uncertainty in Illness Scale data. We collected clinical characteristics through the medical records. Data analysis was performed using descriptive statistics, an independent t test, a 1-way analysis of variance, and a Pearson correlation test. We used a multiple linear regression analysis with significant variables in the univariate analysis to determine which variables had a significant impact on illness uncertainty. RESULTS: The mean Mishel Uncertainty in Illness Scale score was 52.33 (12.93). We identified age ( P = .002), education level (high school graduation, P = .014; college or higher, P < .001), anxiety ( P < .001), and social support ( P < .001) as factors affecting illness uncertainty. CONCLUSION: Patients with UIAs who underwent coil embolization did not exhibit severe illness uncertainty. The factors affecting illness uncertainty were age, educational level, anxiety, and social support. This study provides insight into illness uncertainty in this patient population and may help develop appropriate nursing interventions., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 American Association of Neuroscience Nurses.)

Background: The flow diversion technique is increasingly used for reconstructive endovascular treatment of fusiform cerebral aneurysms. Double stenting with the Low-profile Visualized Intraluminal Support (LVIS) Blue stent is one of the flow diversion techniques. The aim of this study was to analyze the clinical and angiographic outcomes of LVIS Blue double stenting for fusiform cerebral aneurysms., Methods: Between March 2016 and July 2020, double LVIS Blue stenting was attempted in 25 fusiform cerebral aneurysms. Patient medical records and radiological images were carefully reviewed., Results: The technical success rate was 100% (25/25). Six aneurysms (24.0%) were located in the anterior circulation and 19 aneurysms (76.0%) were located in the posterior circulation. Intraprocedural thromboembolic complications occurred in 1 patient (4.0%). During the follow-up period (30.8 ± 14.2 months), there were no deaths or delayed complications. The mean angiographic follow-up duration was 28.2 ± 12.8 months. Follow-up angiography revealed complete obliteration (O'Kelly-Marotta D) in 21 (84.0%) patients and near-complete obliteration (O'Kelly-Marotta C + 2 matched with Kamran-Byrne grade 3) in 2 (8.0%) patients. Two patients (8.0%) showed worsening of obliteration grades. One (4.0%) patient required retreatment. There was no significant in-stent stenosis or branch occlusion covered by stents., Conclusions: Double stenting using LVIS Blue stents for the treatment of fusiform cerebral aneurysms is effective and safe., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: The trend in the initial severity of aneurysmal subarachnoid hemorrhage (SAH) is unclear. This study aimed to evaluate whether there was an improvement in the initial severity of SAH over time., Methods: From January 1, 2005, to December 31, 2020, we identified patients who visited the emergency department of our institution with SAH due to intracranial aneurysm rupture. We identified the Hunt Hess (HH) grade and modified Fisher grade of each patient from the medical records, and the Mann-Kendal method was used to estimate the trend of each grade system., Results: A total of 547 patients with SAH were identified. The mean age of the patients was 59.3 years (standard deviation (SD), 14.6). The mean aneurysm size was 6.9 mm (SD, 4.6 mm). The most frequent aneurysm location was the anterior communicating artery (28.7%). In the Mann-Kendal estimates for the analysis of the trend, there was no statistically significant grade throughout the HH and modified Fisher grades. Similarly, there was no improvement throughout all grades in the modified Fisher grade over time., Conclusions: The initial severity of SAH due to cerebral aneurysm rupture did not improve over time.

Objective: Stent-assisted coil embolization (SAC) has been increasingly used to treat various types of intracranial aneurysms. Delayed thromboembolic complications are major concerns regarding this procedure, so dual antiplatelet therapy with aspirin and clopidogrel is needed. However, clinicians vary the duration of dual antiplatelet therapy after SAC, and no randomized study has been performed. This study aims to compare the safety and efficacy of long-term (12 months) dual antiplatelet therapy and shortterm dual antiplatelet therapy (6 months) after SAC for patients with unruptured intracranial aneurysms (UIAs)., Methods: This is a prospective, randomized and multicenter trial to investigate the optimal duration of dual antiplatelet therapy after SAC in patients with UIAs. Subjects will receive dual antiplatelet therapy for 6 months (short-term group) or 12 months (longterm group) after SAC. The primary endpoint is the assessment of thromboembolic complications between 1 and 18 months after SAC. We will enroll 528 subjects (264 subjects in each group) and perform 1 : 1 randomization. This study will involve 14 topperforming, high-volume Korean institutions specializing in coil embolization., Results: The trial will begin enrollment in 2022, and clinical data will be available after enrollment and follow-up., Conclusion: This article describes that the aim of this prospective randomized multicenter trial is to compare the effect of short-term (6 months) and long-term (12 months) dual antiplatelet therapy on UIAs in patients undergoing SAC, and to find the optimal duration.

Objective: Endovascular treatment of large, wide-necked intracranial aneurysms by coil embolization is often complicated by low rates of complete occlusion and high rates of recurrence. A flow diverter device has been shown to be safe and effective for the treatment of not only large and giant unruptured aneurysms, but small and medium aneurysms. However, in Korea, its use has only recently been approved for aneurysms <10 mm. This study aims to compare the safety and efficacy of flow diversion and coil embolization for the treatment of unruptured aneurysms ≥7 mm., Methods: The participants will include patients aged between 19 and 75 years to be treated for unruptured cerebral aneurysms ≥7 mm for the first time or for recurrent aneurysms after initial endovascular coil embolization. Participants assigned to a flow diversion cohort will be treated using any of the following devices : Pipeline Flex Embolization Device with Shield Technology (Medtronic, Minneapolis, MN, USA), Surpass Evolve (Stryker Neurovascular, Fremont, CA, USA), and FRED or FRED Jr. (MicroVention, Tustin, CA, USA). Participants assigned to a coil embolization cohort will undergo traditional endovascular coiling. The primary endpoint will be complete occlusion confirmed by cerebral angiography at 12 months after treatment. Secondary safety outcomes will evaluate periprocedural and post-procedural complications for up to 12 months., Results: The trial will begin enrollment in 2022, and clinical data will be available after enrollment and follow-up., Conclusion: This article describes the aim and design of a multi-center, randomized, open-label trial to compare the safety and efficacy of flow diversion versus traditional endovascular treatment for unruptured cerebral aneurysms ≥7 mm.

Objective: The aim of this study was to identify predictive factors for hemorrhagic cerebral hyperperfusion syndrome (hCHS) after direct bypass surgery in adult nonhemorrhagic moyamoya disease (non-hMMD) using quantitative parameters on rapid processing of perfusion and diffusion (RAPID) perfusion CT software., Methods: A total of 277 hemispheres in 223 patients with non-hMMD who underwent combined bypass were retrospectively reviewed. Preoperative volumes of time to maximum (Tmax) > 4 seconds and > 6 seconds were obtained from RAPID analysis of perfusion CT. These quantitative parameters, along with other clinical and angiographic factors, were statistically analyzed to determine the significant predictors for hCHS after bypass surgery., Results: Intra- or postoperative hCHS occurred in 13 hemispheres (4.7%). In 7 hemispheres, subarachnoid hemorrhage occurred intraoperatively, and in 6 hemispheres, intracerebral hemorrhage was detected postoperatively. All hCHS occurred within the 4 days after bypass. Advanced age (OR 1.096, 95% CI 1.039-1.163, p = 0.001) and a large volume of Tmax > 6 seconds (OR 1.011, 95% CI 1.004-1.018, p = 0.002) were statistically significant factors in predicting the risk of hCHS after surgery. The cutoff values of patient age and volume of Tmax > 6 seconds were 43.5 years old (area under the curve [AUC] 0.761) and 80.5 ml (AUC 0.762), respectively., Conclusions: In adult patients with non-hMMD older than 43.5 years or with a large volume of Tmax > 6 seconds over 80.5 ml, more prudence is required in the decision to undergo bypass surgery and in postoperative management.

Background: The role of the inhibition rate of VerifyNow in assessing the thromboembolic risk of coil embolization for unruptured intracranial aneurysms is unclear., Objective: To carry out a retrospective study to determine whether the inhibition rate could provide additional help in predicting thromboembolic events when it was used for patients with a P2Y12 reaction unit (PRU) level of 220 or lower., Methods: Patients who underwent coil embolization for unruptured aneurysms with an appropriate PRU level (PRU 220 or lower) between January 1, 2015 and December 31, 2018 were analyzed. A total of 954 patients with 1020 aneurysms were included in this study. The primary outcome was the thromboembolic events occurring within 30 days after coil embolization. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were obtained to determine the quantitative predictive ability of the inhibition rate. The optimal cut-off value was derived using the Youden index., Results: Thromboembolic events developed in 11 patients (1.08% of 1020 procedures). The AUC of the ROC curve was 0.83. The optimal cut-off value of the inhibition rate derived using the maximum Youden index was 22.0%. A sensitivity test using a multiple logistic regression analysis demonstrated that the inhibition rate was a significant variable for predicting thromboembolic events., Conclusions: The inhibition rate can be used to determine high thromboembolic risks for patients with PRU levels of 220 or lower. The optimal cut-off value of the inhibition rate was 22.0% when the PRU level was 220 or less., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion (CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software. Short- and long-term clinical outcomes, including complications and neurological status, were also analyzed. Postoperatively, the volume of time-to-max (Tmax) > 6 s decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 78 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 7 ml; p = 0.000). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 72 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 5 ml; p = 0.000). In addition, the patients' neurological condition improved significantly (p < 0.001). Only one patient (2.3%) showed progression of infarction. Urgent EIB using strict indications can be a feasible treatment for IAT-ineligible patients with AIS due to large vessel occlusion or stenosis., (© 2022. The Author(s).)

Objective: Drug-eluting stents and balloons are occasionally used to reduce restenosis in medically intractable intracranial atherosclerotic stenosis. The authors aimed to determine whether such drugs can cause neurotoxicity due to local effects in a rat model., Methods: Intra-arterial catheters were placed in the right common carotid artery of rats. Mannitol was injected to transiently open the brain-blood barrier (BBB), followed by high-dose drug (paclitaxel and rapamycin) injection. The optimal time interval of transient BBB opening for maximal drug penetration was determined to be 10 minutes. Paclitaxel and rapamycin were intraarterially administered in various doses. All the rats were neurologically evaluated, and their brain tissues were histologically examined., Results: Neither neurological deficits nor histological abnormalities were observed in all the rats., Conclusion: Paclitaxel and rapamycin did not cause neurotoxicity in a rat model with transient BBB opening.

Objective: The treatment of multiple intracranial aneurysms (MIAs) involves various modalities and sometimes requires staged operations. This study aimed to prove the efficacy and safety of one-stage multiple craniotomies (OSMC) for multiple cerebral aneurysms., Methods: We retrospectively reviewed the medical records of the patients who underwent treatment for intracranial aneurysms between May 2003 and April 2020. The surgical results, complications, and lengths of hospital stay were compared between the patients who underwent OSMC and those who underwent multistage multiple craniotomies., Results: The demographic characteristics of the OSMC and multistage multiple craniotomies groups (n = 82 and 43, respectively) were similar. There were no statistically significant differences between the 2 groups when the amount of blood transfused, complications, and surgical results were compared (P = n.s. for all); however, the operation time and hospitalization period (353.9 minutes vs. 490.3 minutes and 12.3 days vs. 21.8 days, respectively; P = 0.001 for both) were shorter in the OSMC group. The treatment cost (17,000 USD vs. 22,000 USD, P = 0.001) was lower in the OSMC group., Conclusions: OSMC for aneurysm clipping in patients with MIAs is a relatively safe and economical method. Furthermore, it has good clinical outcomes. This new surgical method is worthwhile in that it can be applied to patients who are afraid to undergo multiple surgeries, and we suggest that it is an efficient, low-cost option for the treatment of MIAs., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Placement of a single transverse stent via the nondominant A1 across the anterior communicating artery (AComA) into the contralateral A2 can provide sufficient neck coverage for wide-necked bifurcation AComA aneurysms. The authors described the feasibility, safety and long-term outcomes of this technique., Methods: Between January 2015 and February 2018, placement of a single transverse stent via the nondominant A1 was attempted in 17 wide-necked bifurcation AComA aneurysms. The authors reviewed the medical records and radiological studies., Results: The technical success rate was 94.1% (16/17). Periprocedural thromboembolic complications occurred in one patient (6.3%) without permanent neurological deficits. The mean clinical follow-up duration was 39.9±9.8 months. No deaths or delayed thromboembolic complications occurred. The mean angiographic follow-up duration was 38.9±9.8 months. The immediate and final follow-up complete occlusion rates were 87.4 and 93.7%, respectively. There was no recanalization during the follow-up period., Conclusion: Placement of a single transverse stent via the nondominant A1 across the AComA into the contralateral A2 is a feasible and relatively safe endovascular technique for the treatment of wide-necked bifurcation AComA aneurysms, with good long-term occlusion rates and a reasonable complication rate, if only the nondominant A1 is applicable.

Background: The recurrence rate of posterior communicating artery (Pcom) aneurysms after endovascular treatment (EVT) is higher than that for aneurysms located in other sites. However, it is still unclear what mechanisms are responsible for the recanalization of cerebral aneurysms. In this investigation, we compared hemodynamic factors related with recanalization of Pcom aneurysms treated by endoluminal coiling using computational fluid dynamics (CFD) with high-resolution three-dimensional digital subtraction angiography images., Methods: Twenty patients were enrolled. A double-sinogram acquisition was performed with and without contrast injection after coil embolization to get true blood vessel lumen by relatively complementing the first sinogram with the second. Adaptive Cartesian meshing was performed to produce vascular wall objects for CFD simulation. The boundary condition for inlet (ICA) was set for dynamic velocity according to the cardiac cycle (0.8 s). Hemodynamic parameters were recorded at two specific points (branching point of Pcom and residual sac). The peak pressure, peak WSS, and oscillatory shear index (OSI) were recorded and analyzed., Results: The median age was 61.0 years, and 18 patients (90%) were female. During a median follow-up of 12 months, seven (35%) treated aneurysms showed recanalization. The median aneurysm volume was significantly higher, and aneurysm height and neck sizes were significantly longer in the recanalization group than those in the stable group. At the branching point of the Pcom, the peak pressure, peak WSS, or OSI did not significantly differ between the two groups. The only statistically significant hemodynamic parameter related with recanalization was the OSI at the aneurysm point. Multivariate logistic regression showed that with an increase of 0.01 OSI at the aneurysm point, the odds ratio for the aneurysm recanalization was 1.19., Conclusions: A higher OSI is related with recanalization after coil embolization for a Pcom aneurysm., (© 2020. Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: We aimed to analyze outcomes of clipping and coiling in treating unruptured intracranial aneurysms (UIAs) in elderly patients and to identify the age at which perioperative risk increases based on national cohort data in South Korea., Methods: The incidence of perioperative intracranial hemorrhage (ICRH), perioperative cerebral infarction (CI), mortality, and moderate to severe disability data of the patients who underwent coiling or clipping for UIAs were retrieved. Estimated breakpoint (EBP) was calculated to identify the age at which the risk of treatment increases., Results: A total of 38,207 patients were treated for UIAs. Among these, 22,093 (57.8%) patients underwent coiling and 16,114 (42.2%) patients underwent clipping. The incidence of ICRH, requiring a secondary operation, within 3 months in patients ≥ 65 years that underwent coiling and clipping was 1.13% and 4.81%, respectively, and that of both groups assessed were significantly higher in patients ≥ 75 years (coiling, P = 0.013, relative risk (RR) 1.81; clipping, P = 0.015) than younger patients. The incidence of CI within 3 months in patients aged ≥ 65 was 13.90% and 9.19% in the coiling and clipping groups, respectively. The incidence of CI after coiling in patients aged ≥ 75 years ( P < 0.001, RR 1.96) and after clipping in patients aged ≥ 70 years ( P < 0.001, RR 1.76) was significantly higher than that in younger patients. The mortality rates within 1 year in patients with perioperative ICRH or CI were 2.41% and 3.39% for coiling and clipping groups, respectively, in patients ≥ 65. These rates increased significantly at age 70 in the coiling group and at age 75 for the clipping group ( P = 0.012 and P < 0.001, respectively)., Conclusion: The risk of treatment increases with age, and this risk increases dramatically in patients aged ≥ 70 years. Therefore, the treatment decisions in patients aged ≥ 70 years should be made with utmost care., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2021 The Korean Academy of Medical Sciences.)

Objective: Implantation of drug-eluting stents (DES) for extra- and intracranial atherosclerotic stenoses is an emerging topic. It has the potential benefit of preventing recurrent stroke with a reduced rate of in-stent restenosis (ISR)., Methods: Patients who underwent extra- or intracranial stenting using DES in a single institution were retrospectively reviewed with long-term angiographic and clinical follow-up data., Results: Twenty-one patients, 9 (42.9%) with extracranial lesions and 12 (57.1%) with intracranial lesions, were included. The most common symptom was cerebral infarction (71.4%), followed by vertebrobasilar insufficiency (19.1%) and transient ischemic attack (9.5%). All patients achieved technical success, with the mean degree of stenosis of 85.9±6.3% before the procedure and 19.5±5.9% after the procedure. All patients showed clinical improvement and no symptomatic recurrence was reported during the mean clinical follow-up period of 45.5±8.9 months. The significant ISR was observed in one patient (4.8%) during the mean radiological follow-up period of 42.8±10.0 months., Conclusions: Implantation of drug-eluting stents for symptomatic extra- and intracranial atherosclerotic stenoses is feasible and has the potential benefit of reducing the rate of ISR.

Background: Neuromuscular block (NMB) used during general anesthesia induces transient skeletal muscle paralysis, but patient movements during endovascular coiling still occur to some degree. Compared with moderate NMB, deep NMB may further improve the intervention condition during endovascular coiling for unruptured cerebral aneurysms; however, little research has focused on the angiographic image quality., Methods: This prospective, randomized, double-blind clinical trial included 58 patients treated for unruptured cerebral aneurysms with endovascular coiling under general anesthesia. Patients were randomly allocated to either the deep NMB group (post-tetanic count 1 or 2) or the moderate NMB group (train-of-four 1 or 2). The primary outcome was the proportion of patients with a satisfactory intervention condition assessed by surgeons after the procedure using a 5-point intervention condition rating scale (ICRS) from 1 (unable to obtain image) to 5 (optimal); ICRS 5 was defined as satisfactory., Results: There were significantly more cases of satisfactory intervention condition in the deep NMB group than in the moderate NMB group (82.1% vs 51.7%, p=0.015). The frequency of each ICRS score was significantly different between the groups (ICRS 5/4/3/2/1: 23/5/0/0/0 vs 15/9/2/3/0, p=0.035). The incidence of major patient movement requiring rescue muscle relaxant was 10.3% in the moderate NMB group and 0% in the deep NMB group (p=0.237). The drugs used to maintain hemodynamic stability were not significantly different between the two groups., Conclusions: Deep NMB improves the intervention condition during endovascular coiling by improving the image quality., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Coil protrusion occasionally occurs during embolization and can lead to thromboembolic complications. We aimed to evaluate the efficacy of rescue stenting procedures with a low-profile stent system (LVIS Jr.) for treating ruptured intracranial aneurysms during complicated coil embolization., Methods: We performed a retrospective review to identify patients who had subarachnoid hemorrhage and were treated with LVIS Jr. stent rescue therapy. We enrolled 15 patients with intracranial aneurysms and evaluated the technical success and immediate postprocedural clinical and angiographic outcomes., Results: All 15 patients underwent successful rescue-stent treatment, and no thrombotic or hemorrhagic complications occurred. Immediate postprocedural angiography revealed complete aneurysm occlusion in 40% (6/15) of the patients, whereas 60% (9) of the patients had a residual neck. Among the 12 patients who underwent follow-up angiography, 10 (83.3%) patients had complete aneurysm occlusion, 1 (8.3%) had a residual neck, and 1 (8.3%) showed an increase in the filling status of the aneurysm. There were no thrombotic complications during the follow-up period., Conclusions: Our findings indicate that LVIS Jr. stent rescue therapy is clinically useful for handling coil protrusion during the embolization of ruptured intracranial aneurysms., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: To analyze trends in the incidence and treatment of diseases associated with ischemic stroke, namely, cerebral infarction (CI), cerebral arterial stenosis (CASTN), and moyamoya disease (MMD), based on Korean National Health Insurance Service (NHIS) data from 2008 to 2016., Methods: Data was extracted from the national health-claim database provided by the NHIS for 2008-2016 using International Classification of Diseases codes. The crude and age-standardized incidences of each disease (CI, CASTN without a history of CI, and MMD) were calculated; additional analyses were conducted according to age and sex. Trends in the number of patients undergoing treatment according to treatment method were analyzed for each disease using the Korean Classification of Diseases procedure codes., Results: In 2016, the total number of adults with newly diagnosed CI was 83939, reflecting a 9.4% decrease from that in 2008. The agestandardized incidence of CI in adults was 153.2 per 100000 person-years in 2016, reflecting a 37.2% decrease from that in 2008, while that of CASTN was 167.3 per 100000 person-years in 2016, reflecting a 73.3% increase from that in 2008. Among treated cases, the number of patients who underwent intra-arterial (IA) treatment, including IA fibrinolysis and mechanical thrombectomy, showed the most prominent increase, increasing at an annual rate of 25.8%. For CASTN, the number of cases treated with carotid artery stenting or balloon angioplasty (CAS) showed the most prominent increase, increasing at a rate of 69.8% over the 9-year period. For MMD, the total number of patients with newly diagnosed MMD and that with adult MMD demonstrated significantly increasing trends, while the number of pediatric patients with newly diagnosed MMD declined by 18.0% over the 9-year period. The age-standardized incidences of pediatric and adult MMD in 2016 were 2.4 and 3.4 per 100000 person-years, respectively., Conclusion: Although the incidence of CI showed a declining trend over a 9-year period, the number and proportion of patients treated for CI increased. Meanwhile, the incidence of CASTN and the number of patients treated for CASTN have demonstrated increasing trends since 2008. On the other hand, the number of patients diagnosed with pediatric MMD decreased, despite no significant change in the incidence. In contrast, the number of patients and the incidence of adult MMD increased. These trends reflect changes in the population structure, gains in the accessibility of imaging examinations, and the development of endovascular techniques.

Objective: To analyze the incidence and treatment trends of hemorrhagic stroke (HS), according to HS subtypes, using nationwide data in Korea from January 2008 to December 2016., Methods: We used data from the national health-claim database provided by the National Health Insurance Service for 2008-2016 using the International Classification of Diseases. The crude incidence and age-standardized incidence of each disease associated with HS, which included intracranial aneurysm (IA), hypertensive intracerebral hemorrhage (ICH), and arteriovenous malformation (AVM), were calculated and additional analysis was conducted according to age and sex. Changes in trends in treatment methods and number of treatments were analyzed for each cerebrovascular disease using the Korean Classification of Diseases procedure codes., Results: In 2016, the total number of newly diagnosed adult patients with HS was 24169, showing a decrease by 7.0% since 2008; the age-standardized incidence of HS was 46.2 per 100000 person-years. The age-standardized incidence of unruptured IA (UIA) in adults was 71.4 per 100000 person-years-increased by 2.6-fold since 2008-while that of ruptured IA (RIA) was 12.6 per 100000 person-years, which had decreased at a rate of 20.3% since 2008. The number of coil embolization (CE) for UIA increased by 3.4-fold over 9 years and exceeded that of clipping since 2008. With respect to RIA, CE increased by 2.0-fold over 9 years and exceeded that of clipping from 2014. As for spontaneous ICH in adults, the age-standardized incidence was 31.3 per 100000 personyears in 2016-decreased by 34.7% since 2008-and 14.6% of patients diagnosed with ICH were treated in 2016, which was not significantly different from the proportion of patients treated since 2008. The age-standardized incidence of unruptured AVM (UAVM) was 2.0 per 100000 person-year in 2016, while that of ruptured AVM (RAVM) was 2.4 per 100000 person-years in 2016, showing a decreasing rate of 17.2% from 2008. The total number of treated patients with AVM declined since 2014., Conclusion: In Korea, age-related cerebral vascular diseases, such as RIA, ICH, and RAVM, demonstrated a declining trend in agestandardized incidence; meanwhile, UIA and UAVM demonstrated an increased trend in both crude incidence and age-standardized incidence for 9 years. The increase in the elderly population, management of hypertension, and development of diagnostic and endovascular techniques appear to have influenced this trend.

Objective: To investigate the safety and unexpected finding of the intraoperative neuromonitoring (IONM) including somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) during microsurgical clipping of an unruptured anterior choroidal artery (AChA) aneurysm., Patients and Methods: From January 2011 to March 2018, the neurophysiological, clinical, and radiological data of 115 patients who underwent microsurgical clipping for an unruptured AChA aneurysm under IONM were retrospectively analyzed. The incidence of ischemic complications after microsurgical clipping of unruptured AChA aneurysms as well as the false-negative rate, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of IONM during surgery were calculated., Results: Ischemic complications after the microsurgical clipping of an AChA aneurysm under IONM occurred in 7 of 115 patients (6.08%). Among them, 3 were symptomatic (2.6%). The false-negative rate of IONM for ischemic complications was 6.08% (7 patients). High specificity; 100% (95% confidence interval [95% CI] = 0.972-1.000), PPVs; 100% (95% CI = 0.055-1.000), and NPVs; 93% (95% CI = 0.945-0.973) with low sensitivity; 11.1% (95% CI = 0.006-0.111) were calculated., Conclusions: IONM including transcranial MEP during microsurgical clipping of unruptured AChA aneurysm might have limited usefulness. Therefore, other MEP monitoring using direct cortical stimulation or modified transcranial methodology should be considered to compensate for it., (Copyright © 2019. Published by Elsevier B.V.)

Objective: To analyze the angiographic features and clinical course, including treatment outcomes and the natural course, of fusiform middle cerebral artery aneurysms (FMCAAs) according to their location, size, and configuration., Methods: We reviewed the literature on adult cases of FMCAAs published from 1980 to 2018; from 25 papers, 112 FMCAA cases, for which the location, size, and configuration could be identified, were included in this study. Additionally, 33 FMCAA cases in our hospital were included, from which 16 were assigned to the observation group. Thus, a total of 145 adult FMCAA cases were included. We classified the FMCAAs according to their location (l-type 1, beginning from prebifurcation; l-type 2, beginning from bifurcation; l-type 3, beginning from postbifurcation), size (small, <10 mm; large, ≥10 mm; giant, ≥25 mm), and configuration (c-type 1, classic dissecting aneurysm; c-type 2, segmental ectasia; c-type 3, dolichoectatic dissecting aneurysm)., Results: The c-type 3 was more commonly diagnosed with ischemic symptoms (31.8%) than hemorrhage (13.6%), while 40.9% were found accidentally. In contrast, c-type 2 was more commonly diagnosed with hemorrhagic symptoms (14.9%) than ischemic symptoms (10.6%), and 72.3% were accidentally discovered. According to location, ischemic symptoms and hemorrhage were the most frequent symptoms in l-type 1 (28.6%) and l-type 3 (34.6%), respectively. Most of l-type 2 FMCAAs were found incidentally (68.4%). Based on the size of FMCAAs, only 11.1% of small aneurysms were found to be hemorrhagic, while 18.9% and 26.0% of large and giant aneurysms were hemorrhagic, respectively. Although four aneurysms of the 16 FMCAAs in the observation group increased in size and one aneurysm decreased in size during the observation period, no rupture was seen in any case and there were no significant predictors of aneurysm enlargement. Of 104 FMCAAs treated, 14 cases (13.5%) were aggravated than before surgery and all the aggravated cases were l-type 1., Conclusion: While ischemic symptoms occurred more frequently in l-type 1 and c-type 3, hemorrhagic rather than ischemic symptoms occurred more frequently in l-type 3 and c-type 2. In case of l-type 1 FMCAAs, more caution is required in determining the treatment due to the relatively high complication rate.

Objective: This study investigated the effect of residual stenosis after carotid artery stenting (CAS) on periprocedural and long-term outcomes., Methods: Patients treated with CAS for symptomatic or asymptomatic carotid arterial stenosis were consecutively enrolled. Residual stenosis was estimated from post-procedure angiography findings. The effects of residual stenosis on 30-day periprocedural outcome and times to restenosis and clinical outcome were analyzed using logistic regression models and Wei-Lin-Weissfeld models, respectively., Results: A total of 412 patients (age, 64.7 ± 17.0 years; male, 82.0%) were enrolled. The median baseline stenosis was 80% (interquartile range [IQR], 70-90%), which improved to 10% (0-30%) for residual stenosis. Residual stenosis was significantly associated with periprocedural outcome (adjusted odds ratio, 0.983; 95% confidence interval [CI], 0.965-0.999, P = 0.01) after adjustment for baseline stenosis, age, hypertension, symptomaticity, and statin use. Over the 5-year observation period, residual stenosis did not increase the global hazard for restenosis and clinical outcome (adjusted hazard ratio, 1.011; 95% CI, 0.997-1.025. In the event-specific model, residual stenosis increased the hazard for restenosis (adjusted hazard ratio, 1.041; 1.012-1.072) but not for clinical outcome (adjusted hazard ratio, 1.011; 0.997-1.025)., Conclusions: Residual stenosis after carotid artery stenting may be useful to predict periprocedural outcome and restenosis., Competing Interests: The authors have declared that no competing interests exist.

Headache may be the most common presenting symptom of unruptured intracranial aneurysms. Unruptured intracranial aneurysm can be found in the work-up for headache but direct causality is not clear. Most of the headaches have been thought to be incidental symptoms of unruptured intracranial aneurysms. If high-risk patients with symptoms such as headache could be selected it would help in diagnosing unruptured intracranial aneurysms. Many aspects of unruptured intracranial aneurysm-associated headaches are unclear, including the mechanism, discriminating characteristics, and localization. This article reviews basic knowledge on cerebral aneurysm and headache, and describes the possible mechanism and characteristics of aneurysm-associated headaches., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The number of endovascular treatment procedures performed for cerebral aneurysms has markedly increased. However, little is known about the annual effective radiation dose to medical staff in neurointervention fields. We performed a retrospective observational study to investigate the real-time radiation dose to surgeons, nurses, anesthesiologists, and radiologic technologists during endovascular treatment of intracranial aneurysms., Methods: We measured the real-time radiation doses for 2 weeks using standard and reinforced protection, during which 28 procedures were performed, including 23 coil embolizations for unruptured intracranial aneurysms. Four procedures were excluded because of an inadequately equipped sensor, which resulted in inappropriate data collection. The procedure time was defined from intubation to extubation. Five RaySafe i2 detectors were installed at the chest level of the operator, attending nurse, radiologic technologist, and anesthesiologist and just inside the front door of the hybrid operating room., Results: The median doses per session with standard protection to the operator, attending nurse, anesthesiologist, and radiologic technologist were 11.16, 2.60, 4.76, and 1.93 μSv, respectively. The dose to the operator, attending nurse, and anesthesiologist had decreased to 6.63, 0.39, and 1.52 μSv under reinforced protection, respectively. However, the session dose for the radiologic technologist had increased to 3.12 μSv., Conclusions: We confirmed the differences in the amount of radiation exposure for different roles. An additional lead screen, which provided more effective protection on the operator side, was proved effective for attenuating radiation exposure during endovascular treatment. All personnel involved in the hybrid operating room were exposed to acceptable effective doses., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Recently, innovative attempts have been made to identify moyamoya disease (MMD) by focusing on the morphological differences in the head of MMD patients. Following the recent revolution in the development of deep learning (DL) algorithms, we designed this study to determine whether DL can distinguish MMD in plain skull radiograph images., Methods: Three hundred forty-five skull images were collected as an MMD-labeled dataset from patients aged 18 to 50 years with definite MMD. As a control-labeled data set, 408 skull images of trauma patients were selected by age and sex matching. Skull images were partitioned into training and test datasets at a 7:3 ratio using permutation. A total of six convolution layers were designed and trained. The accuracy and area under the receiver operating characteristic (AUROC) curve were evaluated as classifier performance. To identify areas of attention, gradient-weighted class activation mapping was applied. External validation was performed with a new dataset from another hospital., Findings: For the institutional test set, the classifier predicted the true label with 84·1% accuracy. Sensitivity and specificity were both 0·84. AUROC was 0·91. MMD was predicted by attention to the lower face in most cases. Overall accuracy for external validation data set was 75·9%., Interpretation: DL can distinguish MMD cases within specific ages from controls in plain skull radiograph images with considerable accuracy and AUROC. The viscerocranium may play a role in MMD-related skull features. FUND: This work was supported by grant no. 18-2018-029 from the Seoul National University Bundang Hospital Research Fund., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Proximal middle cerebral artery (M1 segment) aneurysms are relatively deeply located in neighboring lenticulostriate arteries, which make them unsuitable for microsurgery. We aimed to investigate the clinical and radiological outcomes of endovascular coiling of M1 segment aneurysms., Methods: Between January 2003 and December 2014, we retrospectively reviewed the medical records of 52 patients (52 aneurysms) from four institutions who underwent endovascular coiling of M1 segment aneurysms. Patients who underwent clinical and radiologic follow-up for more than a year after the procedure were evaluated., Results: The aneurysms were located in the early frontal branch, early temporal branch, and lenticulostriate artery in 28, 15, and nine patients, respectively. Endovascular coiling was achieved in 51 cases and failed in one case. Of these 51 cases, 46 (90.2%) and five (9.8%) were non-ruptured and ruptured aneurysms, respectively. Initial angiographic results revealed complete occlusion in 26 (51.0%), residual neck in 16 (31.4%), and residual sac in nine (17.6%) cases. One failed case had a symptomatic procedural complication of thromboembolism. However, there was no permanent morbidity or mortality. Two major recanalization cases (3.9%) were retreated by endovascular coiling. On multivariable logistic regression analysis, aneurysmal recurrence was significantly related to aneurysm height (OR, 1.887; 95% CI, 1.107 to 3.217; p = 0.020), width (OR, 1.836; CI, 1.127 to 2.992; p = 0.015), and neck (OR, 4.017; CI, 1.220 to 13.232, p = 0.022)., Conclusion: Endovascular coiling of M1 segment aneurysms appeared to be a feasible treatment option with a relatively low-retreatment rate. Aneurysm size was statistically significantly associated with recurrence.

Background: The long-term outcomes of endovascular coiling and surgical clipping for the treatment of unruptured intracranial aneurysms are unclear., Methods: We performed a nationwide retrospective cohort study using claims data from the Korean Health Insurance Review and Assessment Service on patients undergoing surgical clipping or endovascular coiling from 2008 to 2014. Inverse probability treatment weighting for average treatment effect on the treated and the multiple imputation method were used to balance covariates and handle missing values. The primary outcome was all-cause mortality at 7 years., Results: We identified 26 411 patients of whom 11 777 underwent surgical clipping and 14 634 underwent endovascular coiling. After adjustment with the use of inverse probability treatment weighting for average treatment effect on the treated, all-cause mortality rates at 7 years were 3.8% in the endovascular coiling group and 3.6% in the surgical clipping group (HR 1.05; 95% CI 0.86 to 1.28; P=0.60, log-rank test). The adjusted probabilities of aneurysm rupture at 7 years were 0.9% after endovascular coiling and 0.7% after surgical clipping (HR 0.9; 95% CI 0.61 to 1.34; P=0.63, log-rank test). The probabilities of retreatment at 7 years after adjustment were 4.9% in the endovascular coiling group and 3.2% in the surgical clipping group (HR 1.52; 95% CI 1.28 to 1.81; P<0.001, log-rank test)., Conclusions: All-cause mortality at 7 years was similar between the elective surgical clipping and endovascular coiling groups in patients with unruptured aneurysms who had no history of subarachnoid hemorrhage due to aneurysm rupture., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Blood blister-like aneurysms (BBAs) are an important cause of subarachnoid hemorrhage (SAH), but proper treatment is uncertain due to the poor prognosis of these aneurysms. The pathogenesis of BBAs remains unclear and few studies have reported on histological examinations of BBAs because it is difficult to obtain a specimen due to a high risk of intraoperative bleeding. In this report, BBAs were histopathologically examined in two patients who presented with SAH due to rupture of a BBA that was treated with surgical trapping and bypass surgery. BBA specimens including the adjacent internal carotid artery (ICA) walls were obtained intraoperatively. We suggest the pathogenesis of BBAs based on histopathologic examination and microscopic configuration., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Brain herniation is most often the result of severe brain swelling and can rapidly lead to death or brain death. We retrospectively identified radiologic indicators to evaluate the effects of targeted temperature management (TTM) on the extent of cerebral edema and determine the cutoff values that best predict TTM outcomes in patients with large hemispheric infarction. We retrospectively reviewed brain computed tomography (CT) scans of 21 patients with large hemispheric infarctions, who were treated with TTM. We excluded 4 patients whose CT scans were inadequate for evaluation, which left 17 patients. We divided the patients into success and failure groups. TTM failure was defined as death or the need for decompressive hemicraniectomy (DHC) after TTM. Infarction size was measured as the total restricted area in diffusion-weighted imaging that was performed on admission. CT scans were obtained on the first and second days after TTM initiation and then every 2 days. We measured septum pellucidum shifts (SPS) and pineal gland shifts (PGS) on CT scans. The median time from symptom onset to TTM initiation was 14.5 hours. Ten patients were successfully treated with TTM, six patients died, and one patient underwent a DHC. Initial infarction sizes were not significantly different between the success and failure groups (p = 0.529), but the SPS and PGS at 36-72 hours after TTM initiation were (mean SPS: 5.0 vs. 14.9 mm, p = 0.001; mean PGS: 2.3 vs. 7.9 mm, p = 0.001). The sensitivity and negative predictive value for TTM failure caused by cerebral edema (SPS ≥9.25 mm and PGS ≥3.70 mm) at 36-72 hours after TTM initiation were both 100%. The SPS and PGS on CT scans taken 36-72 hours after TTM initiation may help to estimate the effect of TTM on cerebral edema and guide further treatment.

Background: The optimal duration of dual-antiplatelet therapy (DAPT) for preventing delayed thromboembolic events (DTEs) remains unclear. We aimed to determine whether longer DAPT provides improved protection against delayed DTEs., Methods: This retrospective cohort study included 507 stent-assisted coil embolization procedures using a single stent for unruptured intracranial aneurysms. We performed coarsened exact matching according to the duration of maintenance DAPT. DTEs were defined as any neurologic symptoms concerning the stented vascular territory and occurring at 1 month or later after the procedure. After stratification according to DAPT duration (short-term, <9 months; long-term, ≥9 months), the log-rank test and Z-analysis were performed to evaluate the efficacy of long-term DAPT for preventing DTEs., Results: Of 507 treated patients (median follow-up, 44 months), 25 (4.9%) experienced DTEs at 1 month after the procedure. Among all DTEs, 9 (1.8%) were infarctions confirmed on magnetic resonance imaging. Permanent neurologic deficit (modified Rankin Scale score ≥2) occurred in 2 (0.4%) patients. On procedure-to-event analysis, long-term DAPT was not superior for preventing DTEs. Most events occurred within 1 month of switching from DAPT to single-antiplatelet therapy, regardless of DAPT duration. The longest time from the procedure to DTE occurrence was 22 months. Age older than 54.5 years was identified as independent risk factor for DTE-stroke., Conclusions: Compared with short-term DAPT, long-term DAPT delays the occurrence of DTEs but does not lower their incidence. Longer-term DAPT (>9 months) should be considered after stent-assisted coil embolization for unruptured intracranial aneurysms, although its efficacy remains to be clarified., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: Brain arteriovenous malformation (BAVM) is a rare cerebrovascular disease that causes intracranial hemorrhage. Although several reports have demonstrated the epidemiological features of BAVM in Western countries, no epidemiological investigations regarding BAVM have been reported in Korea. The authors aimed to investigate the national epidemiology of ruptured BAVM in a Korean population., Methods: The authors used data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC). The original cohort included approximately 1 million individuals (2% of the Korean population) with 12-year claim data (2002-2013). To construct an initial cohort for investigation, the authors selected 1,016,820 registered individuals in 2005. Subjects with a history of cerebrovascular disease (code I6xx) and BAVM (Q282) between 2002 and 2004 were washed-out to identify incident cases. During the 9-year follow-up (2005-2013), the incidence of BAVM was calculated using the earliest date of diagnosis of ruptured or unruptured BAVM. Direct standardization was applied to the crude incidence. Mortality and disability were evaluated using registration data. Related diagnostic procedures were also analyzed., Results: A total of 8,802,696 person-years of observation were noted. During observation, 308 patients were diagnosed with a ruptured BAVM. The crude incidence of ruptured BAVM was 3.5 per 100,000 person-years. There was no sex difference in incidence. The mortality rate for patients with a ruptured BAVM 1 month after diagnosis was 12.7%. At 1-year and 5-year follow-up examinations, mortality rates were 17.2% and 22.1%, respectively. Severe disability-free survival rates of patients with ruptured AVMs were 75.3% and 69.8% at 1-year and 5-year follow-up, respectively., Conclusions: The standardized incidence of ruptured BAVMs was 3.6 per 100,000 person-years in Korea. Ruptured BAVMs resulted in high mortality and disability rates.

Purpose of Review: Moyamoya disease (MMD) is being increasingly diagnosed with the development of radiological surveillance technology and increased accessibility to medical care. Accordingly, there have been several recent reports on treatment outcomes in MMD. In this review, we summarize recent advances in surgical treatment and outcomes of adult MMD, while addressing related controversies., Recent Findings: Recent studies suggest that revascularization surgery leads to significantly more favorable outcomes for stroke prevention, angiographic and hemodynamic changes, and clinical outcomes than does conservative treatment for adult patients with ischemic MMD. Moreover, direct revascularization methods should be considered as the first-line treatment over indirect methods, although the latter may be considered if a direct method is not possible. In cases of hemorrhagic MMD, several studies have demonstrated that surgical treatment is more effective than conservative treatment in preventing further hemorrhage. In addition to revascularization surgery, endovascular treatment is emerging as a breakthrough therapy for hemorrhagic MMD. Accumulating evidence regarding the surgical treatment of adult MMD suggests the benefit of revascularization over conservative management for both ischemic and hemorrhagic patients. However, the benefit of revascularization in asymptomatic adult MMD remains unclear.

Purpose: Only a few reports of internal carotid artery (ICA) bifurcation aneurysms using the endovascular technique have been published in the current literature. The purpose of this study was to assess how multiple risk factors including angioarchitectural features of ICA bifurcation characteristics may have influenced aneurysmal rupture, recanalization, and retreatment., Methods: Fifty-one patients with 52 ICA bifurcation aneurysms treated with endovascular coiling between July 2003 and July 2015 were retrospectively analyzed. The patients' clinical records, endovascular reports, and clinical and angiographic outcomes were reviewed. We also evaluated risk factors for recanalization and retreatment, including the angioarchitectural anatomy., Results: The clinical outcomes were observed to be satisfactory in 49 patients (96.0%) and unfavorable in 2 patients (4.0%). The risk factor for aneurysmal rupture was young age (P = 0.024). Symptomatic complications due to thromboembolism occurred in 1.9% of cases; no patients suffered a fatal complication. Eleven of 52 ICA bifurcation aneurysms (21.2%) were recanalized within an average of 54.3 ± 33.5 months of follow-up. Among the aneurysms, 4 (7.7%) underwent recoiling. Multivariate analysis showed that ruptured aneurysms (P = 0.006) and a lower packing density (P = 0.048) were risk factors for recanalization. A lower packing density was the only risk factor for retreatment (P = 0.019)., Conclusion: Endovascular treatment of ICA bifurcation aneurysms is considered safe and acceptable. This study showed that the ICA bifurcation aneurysms ruptured more frequently at a younger age. A higher packing density has been shown to reduce major recanalization and retreatment.

Stent-assisted coil embolization technique have broadened indications for endovascular therapy of aneurysms. The Low-profile Visualized Intraluminal Support device (LVIS) is a self-expanding, nitinol single-braid and closed-cell device introduced fairly recently. We aim to evaluate long-term outcome of LVIS device in stent-assisted coiling of intracranial aneurysms. Between October 2012 and February 2013, a total of 55 patients with unruptured wide-necked intracranial aneurysms underwent coil embolization procedures involving LVIS devices. Clinical and anatomic parameters assessed included extent of aneurysmal occlusion, stent deployment status, and delayed complications. Anatomic outcomes were evaluated via DSA, MRA, and plain radiography (PR). Three patients were lost to follow-up after 6 months, but in 37 of 52 qualifying patients (mean follow-up, 27.1 months; range, 12-36 months) post-coiling recanalization was evaluable by DSA or MRA. Only one patient (2.7%) experienced minor recanalization, all others (97.3%) showing complete occlusion. Coil configurations were consistently stable by PR in 15 other patients (mean follow-up, 34.1 months; range, 30-39 months). No migration or altered expansion of stents was evident in 30 patients with available DSA and/or PR images. Three patients (5.8%) suffered delayed cerebral ischemia without neurologic sequelae, all as transient ischemic attacks and all related to withdrawal or change of anti-platelet medications. LVIS device usage in stent-assisted coil embolization of intracranial aneurysms provides excellent long-term results in terms of safety, efficacy and durability., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objective: To investigate nationwide statistics on flow-diverting stent usage for cerebral aneurysm treatment and related mortality data., Methods: We requested data extraction from the National Health Insurance Service claims database using electronic data interchange codes (J3207064, J3207073). Patient and hospital information as well as death statistics were collected from the database., Results: A total of 169 procedures were performed using flow-diverting stents for cerebral aneurysm treatment from November 2014 to December 2016 in Korea. The majority of primary diagnosis was unruptured intracranial aneurysm. During the study period, nine subjects died, including one patient initially diagnosed with subarachnoid hemorrhage. The crude mortality rate was 5.3%. Five patients died within one month after the procedure; therefore, the estimated periprocedural mortality rate was 3.0±1.3%. The mortality rate as of the last day of 2016 was 6.3±2.1%., Conclusion: In a 171 person-year follow-up in a Korean series, nine deaths occurred after flow-diverting stent treatment. The crude mortality rate in Korea (5.3%) was higher than that reported in a previous meta-analysis (3.8%).

Objective: Bilateral cavernous sinus dural arteriovenous fistula (CSdAVF) is very rare, even in Asian countries. The research intended to present clinical and radiologic outcomes of treating such fistulas through endovascular embolization., Materials and Methods: Data was obtained from 220 consecutive patients, with CSdAVF, who were treated from January 2004 to December 2015. Bilateral CSdAVF was identified in 17 patients (7.7%). The clinical and radiologic outcomes of the fistulas were assessed with an emphasis on the technical aspects of treatment., Results: At the time of treatment, 7 and 10 patients presented with bilateral and unilateral symptoms, respectively. In the former cases, 4 patients had progressed from unilateral to bilateral symptoms. Bilateral fistulas were treated with a single-stage transvenous embolization (TVE) in 15 patients, via bilateral inferior petrosal sinuses (IPS) (n = 9) and unilateral IPS (n = 6). In the other 2 patients with one-sided dominance of shunting, only dominant fistula was treated. Two untreated lesions were found on follow-up to have spontaneously resolved after treatment of the dominant contralateral fistula. Of the 34 CSdAVF lesions, complete occlusion was achieved in 32 lesions after TVE. Seven patients (41.2%) developed worsening of cranial nerve palsy after TVE. During the follow-up period, 4 patients obtained complete recovery, whereas the other 3 remained with deficits., Conclusion: With adjustments of endovascular procedures to accommodate distinct anatomical configurations, endovascular treatment for bilateral CSdAVF can achieve excellent angiographic occlusion results. However, aggravation of symptoms after TVE may occur frequently in bilateral CSdAVF. In the patients with one-sided dominance of shunt, treatment of only dominant fistula might be an alternative option.

Purpose To evaluate the effect of middle meningeal artery (MMA) embolization on chronic subdural hematoma (CSDH) and compare the treatment outcomes of MMA embolization and conventional treatment. Materials and Methods All consecutive patients 20 years or older with CSDH were assessed for eligibility. CSDHs with a focal location, a thickness of 10 mm or less, no mass effect, or underlying conditions were excluded. Seventy-two prospectively enrolled patients with CSDH underwent MMA embolization (embolization group; as the sole treatment in 27 [37.5%] asymptomatic patients and with additional hematoma removal for symptom relief in 45 [62.5%] symptomatic patients). For comparison, 469 patients who underwent conventional treatment were included as a historical control group (conventional treatment group; close, nonsurgical follow-up in 67 [14.3%] and hematoma removal in 402 [85.7%] patients). Primary outcome was treatment failure defined as a composite of incomplete hematoma resolution (remaining or reaccumulated hematoma with thickness > 10 mm) or surgical rescue (hematoma removal for relief of symptoms that developed with continuous growth of initial or reaccumulated hematoma). Secondary outcomes included surgical rescue as a component of the primary outcome and treatment-related complication for safety measure. Six-month outcomes were compared between the study groups with logistic regression analysis. Results Spontaneous hematoma resolution was achieved in all of 27 asymptomatic patients undergoing embolization without direct hematoma removal. Hematoma reaccumulation occurred in one (2.2%) of 45 symptomatic patients receiving embolization with additional hematoma removal. Treatment failure rate in the embolization group was lower than in the conventional treatment group (one of 72 patients [1.4%] vs 129 of 469 patients [27.5%], respectively; adjusted odds ratio [OR], 0.056; 95% confidence interval [CI]: 0.011, 0.286; P = .001). Surgical rescue was less frequent in the embolization group (one of 72 patients [1.4%] vs 88 of 469 patients [18.8%]; adjusted OR, 0.094; 95% CI: 0.018, 0.488; P = .005). Treatment-related complication rate was not different between the two groups (0 of 72 patients vs 20 of 469 patients [4.3%]; adjusted OR, 0.145; 95% CI: 0.009, 2.469; P = .182). Conclusion MMA embolization has a positive therapeutic effect on CSDH and is more effective than conventional treatment. © RSNA, 2017.