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Objective: Although a qualitative diagnosis of plaque causing carotid stenosis has been attempted with carotid computed tomography angiography (CaCTA), no clear findings have been reported. We examined the correlation between the plaque CT values and plaque images obtained by magnetic resonance imaging to derive a qualitative diagnosis of the plaque using CaCTA., Methods: Preoperative CaCTA images acquired from patients stented for carotid stenosis were retrospectively analyzed with respect to magnetization-prepared rapid acquisition with gradient echo and time-of-flight magnetic resonance angiography data. Carotid plaques in the stenosed region were quantified in terms of CT density and the plaque/muscle ratio (magnetization-prepared rapid acquisition with gradient echo), and correlations between these 2 features were determined. Plaques were classified as stable or unstable based on the plaque/muscle ratio, with the smallest plaque/muscle ratio observed among plaques positive for intraplaque hemorrhage set as the cutoff value (1.76)., Results: A total of 165 patients (179 plaques) were included. Perioperative complications included minor stroke (n = 3), major stroke (n = 1, fatal), and hyperperfusion (n = 2). The correlation between CT density and the plaque/muscle ratio was nonlinear ( P = 0.0139) and negative ( P < 0.0001). The cutoff point (1.76) corresponded to a CT density of 83 HU, supporting this value as a standard reference for plaque stability., Conclusions: Computed tomography density exhibits a nonlinear ( P = 0.0139) and highly negative correlation ( P < 0.0001) with the plaque/muscle ratio. Our results demonstrate that plaque characteristics can be meaningfully diagnosed based on CaCTA image data., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Some aneurysmal subarachnoid hemorrhage (SAH) patients are delayed in their presentation. This can cause a washout of the subarachnoid hematoma and a potential misdiagnosis. As a result, they may suffer rerupture of the aneurysm and preventable deterioration. We investigated the factors that influence delayed SAH presentation., Methods: Aneurysmal SAH patients treated at 9 stroke centers from 2002 to 2020 were included. Age, gender, pre-SAH modified Rankin scale, World Federation of Neurological Surgeons grade, Fisher group, day of presentation, aneurysm treatment method, past history of cerebral stroke, comorbidity of hypertension and/or diabetes mellitus, and modified Rankin scaleat discharge were assessed retrospectively. We formed 2 groups based on the day of presentation after the onset of SAH: day 0-3 (early) and other (delayed). Logistic regression analyses detected the factors that influenced the day of presentation and outcome for SAH. A P- value <0.05 was considered significant., Results: Delayed presentation comprised 282 cases (6.3%) of 4507 included cases. Logistic regression analyses showed that patients in an urban area, of male gender, low WFNS grade and low Fisher group correlated significantly with a delayed presentation. But delayed presentation did not influence outcome at discharge., Conclusions: Area of residency and gender correlated with delayed presentation after SAH in Japan. Urbanization, male gender, and mild SAH lead patients to delay presentation. The factors underlying these tendencies will be analyzed in a future prospective study., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The COVID-19 pandemic led to profound changes in the organization of health care systems worldwide., Aims: We sought to measure the global impact of the COVID-19 pandemic on the volumes for mechanical thrombectomy, stroke, and intracranial hemorrhage hospitalizations over a three-month period at the height of the pandemic (1 March-31 May 2020) compared with two control three-month periods (immediately preceding and one year prior)., Methods: Retrospective, observational, international study, across 6 continents, 40 countries, and 187 comprehensive stroke centers. The diagnoses were identified by their ICD-10 codes and/or classifications in stroke databases at participating centers., Results: The hospitalization volumes for any stroke, intracranial hemorrhage, and mechanical thrombectomy were 26,699, 4002, and 5191 in the three months immediately before versus 21,576, 3540, and 4533 during the first three pandemic months, representing declines of 19.2% (95%CI, -19.7 to -18.7), 11.5% (95%CI, -12.6 to -10.6), and 12.7% (95%CI, -13.6 to -11.8), respectively. The decreases were noted across centers with high, mid, and low COVID-19 hospitalization burden, and also across high, mid, and low volume stroke/mechanical thrombectomy centers. High-volume COVID-19 centers (-20.5%) had greater declines in mechanical thrombectomy volumes than mid- (-10.1%) and low-volume (-8.7%) centers (p < 0.0001). There was a 1.5% stroke rate across 54,366 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.9% (784/20,250) of all stroke admissions., Conclusion: The COVID-19 pandemic was associated with a global decline in the volume of overall stroke hospitalizations, mechanical thrombectomy procedures, and intracranial hemorrhage admission volumes. Despite geographic variations, these volume reductions were observed regardless of COVID-19 hospitalization burden and pre-pandemic stroke/mechanical thrombectomy volumes.

Background: Patency of the middle cerebral artery (MCA) in acute ischemic stroke with internal carotid artery (ICA) occlusions is associated with less severe stroke and favorable outcomes. However, thrombus migration to distal intracranial vessels may lead to unfavorable outcomes. We investigated the influence of thrombus migration on clinical outcomes in patients with ICA occlusions and patent MCA., Materials and Methods: We retrospectively analyzed patients with acute ischemic stroke compromising ICA occlusions and patent MCA who were consecutively admitted to our hospital between January 2006 and March 2016. Thrombus migration was assessed (1) by analyzing the discrepancies in arterial occlusion sites between initial imaging and follow-up imaging and (2) by analyzing how occlusion sites changed during endovascular therapy., Results: Thirty-eight patients (mean age: 74.9 years; 23 men, 15 women, median National Institutes of Health Stroke Scale score = 7.5) with ICA occlusions and patent MCA were ultimately included. We identified 10 patients (26%) with thrombus migration (spontaneous: 3; during endovascular therapy: 7). Patients with thrombus migration had higher rates of unfavorable functional outcomes (modified Rankin Scale scores 3-6 at 90 days) than those without thrombus migration (90% vs. 39%, p < .01). Multivariate analysis showed that thrombus migration was independently related to unfavorable functional outcomes (odds ratio, 42.9; 95% confidence interval, 1.5-1211.0; p = .03)., Conclusion: Thrombus migration in cases of ICA occlusion with patent MCA is associated with poor prognosis. Careful monitoring is required under these conditions even if the initial clinical presentation is mild., Competing Interests: Declaration of Competing Interest Akira Ishii has received lecturing fees from Medtronic. Jun-ichi Kira is supported by grants from JSPS KAKENHI (Grant No.16H02657) and Health and Labor Sciences Research Grants on Intractable Diseases (H29-Nanchitou (Nan)-Ippan-043), and received consultant fees, speaking fees and/or honoraria from Novartis Pharma, Mitsubishi Tanabe Pharma, Boehringer Ingelheim, Teijin Pharma, Takeda Pharmaceutical Company, Otuka Pharmaceutical, Astellas Pharma, Pfizer Japan, Eisai. The other authors have no conflicts to report., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background and Purpose- For patients with large vessel occlusion, neuroimaging biomarkers that evaluate the changes in brain tissue are important for determining the indications for mechanical thrombectomy. In this study, we applied deep learning to derive imaging features from pretreatment diffusion-weighted image data and evaluated the ability of these features in predicting clinical outcomes for patients with large vessel occlusion. Methods- This multicenter retrospective study included patients with anterior circulation large vessel occlusion treated with mechanical thrombectomy between 2013 and 2018. We designed a 2-output deep learning model based on convolutional neural networks (the convolutional neural network model). This model employed encoder-decoder architecture for the ischemic lesion segmentation, which automatically extracted high-level feature maps in its middle layers, and used its information to predict the clinical outcome. Its performance was internally validated with 5-fold cross-validation, externally validated, and the results compared with those from the standard neuroimaging biomarkers Alberta Stroke Program Early CT Score and ischemic core volume. The prediction target was a good clinical outcome, defined as a modified Rankin Scale score at 90-day follow-up of 0 to 2. Results- The derivation cohort included 250 patients, and the validation cohort included 74 patients. The convolutional neural network model showed the highest area under the receiver operating characteristic curve: 0.81±0.06 compared with 0.63±0.05 and 0.64±0.05 for the Alberta Stroke Program Early CT Score and ischemic core volume models, respectively. In the external validation, the area under the curve for the convolutional neural network model was significantly superior to those for the other 2 models. Conclusions- Compared with the standard neuroimaging biomarkers, our deep learning model derived a greater amount of prognostic information from pretreatment neuroimaging data. Although a confirmatory prospective evaluation is needed, the high-level imaging features derived by deep learning may offer an effective prognostic imaging biomarker.

OBJECTIVEThe clinical outcomes of a direct aspiration first-pass technique (ADAPT) and stent retriever (SR) have been reported to be similar in several observational studies. In this study, procedural and clinical outcomes with ADAPT and SR for the treatment of acute ischemic stroke with large artery occlusion were compared in different time periods.METHODSIn each specific time period, SR and ADAPT were used as the first-line treatment approach for acute ischemic stroke patients with large artery occlusion at the authors' institution. Baseline characteristics, procedural variables, and functional outcome at 90 days were compared between patients treated with SR and those treated with ADAPT. These 2 groups were divided into 3 sequential subgroups to assess the learning curve effects of the endovascular team and individual operators on the procedural variables of each treatment strategy.RESULTSOverall, 89 patients were treated. In the SR group, the recanalization rate was higher (84% vs 65%; p = 0.01) and the procedure time was shorter than in the ADAPT group (median 42 minutes vs 76 minutes, p = 0.04). On the subgroup analysis of the learning curve, the SR group showed more rapid improvement in procedure time than the ADAPT group (p = 0.01 for the team; p < 0.01 for individual operators).CONCLUSIONSIn this initial experience, a higher recanalization rate and shorter procedure time were achieved with SR than with ADAPT. A high recanalization rate with SR was possible with relatively less clinical experience, whereas procedure time dramatically decreased with experience. These observed effects on the learning curve might be useful when choosing the method for initial endovascular treatment of acute ischemic stroke at relatively small stroke centers.

Background: Previous reports have shown significant delays in treatment of in-hospital stroke (IHS). We developed and implemented our IHS alert protocol in April 2014. We aimed to determine the influence of implementation of our IHS alert protocol., Methods: Our implementation processes comprise the following four main steps: IHS protocol development, workshops for hospital staff to learn about the protocol, preparation of standardized IHS treatment kits, and obtaining feedback in a monthly hospital staff conference. We retrospectively compared protocol metrics and clinical outcomes of patients with IHS treated with intravenous thrombolysis and/or endovascular therapy between before (January 2008-March 2014) and after implementation (April 2014-December 2016)., Results: Fifty-five patients were included (pre, 25; post, 30). After the implementation, significant reductions occurred in the median time from stroke recognition to evaluation by a neurologist (30 vs. 13.5min, p<0.01) and to first neuroimaging (50 vs. 26.5min, p<0.01) and in the median time from first neuroimaging to intravenous thrombolysis (45 vs. 16min, p=0.02). The median time from first neuroimaging to endovascular therapy had a tendency to decrease (75 vs. 53min, p=0.08). There were no differences in the favorable outcomes (modified Rankin scale score of 0-2) at discharge or the incidence of symptomatic intracranial hemorrhage between the two periods., Conclusion: Our IHS alert protocol implementation saved time in treating patients with IHS without compromising safety., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Purpose: Periprocedural ischemic stroke is one problem associated with carotid artery stenting (CAS). This study was designed to assess whether preoperative statin therapy reduces the risk of periprocedural ischemic complications with CAS., Methods: In this prospective study at 11 centers, patients with carotid artery stenosis (symptomatic ≥50%, asymptomatic ≥80%) and a high risk of carotid endarterectomy but without previous statin treatments were divided into two groups by low-density lipoprotein cholesterol (LDL-C) levels. With LDL-C ≥120 mg/dl, the pitavastatin-treated (PS) group received pitavastatin at 4 mg/day. With LDL-C <120 mg/dl, the non-PS group received no statin therapy. After 4 weeks, both groups underwent CAS. Frequencies of new ipsilateral ischemic lesions on diffusion-weighted imaging within 72 h after CAS and cerebrovascular events (transient ischemic attack, stroke, or death) within 30 days were assessed., Results: Among the 80 patients enrolled, 61 patients (PS group, n = 31; non-PS group, n = 30) fulfilled the inclusion criteria. New ipsilateral ischemic lesions were identified in 8 of 31 patients (25.8%) in the PS group and 16 of 30 patients (53.3%) in the non-PS group (P = 0.028). Cerebrovascular events occurred in 0 patients in the PS group and in 3 of 30 patients (10.0%) in the non-PS group (P = 0.071). Multivariate analyses demonstrated the pitavastatin treatment (β = 0.74, 95% confidence interval 0.070-1.48, P = 0.042) to be an independent factor for decreasing post-CAS ischemic lesions., Conclusion: Pretreatment with pitavastatin significantly reduced the frequency of periprocedural ischemic complications with CAS.

Although utilization of endovascular treatment of extracranial steno-occlusive lesions except for internal carotid artery stenosis continues to increase, there is no consensus regarding the natural course and standard treatment of these lesions. The aim of this study was to characterize the utility of endovascular treatment for extracranial steno-occlusive lesions except for internal carotid artery stenosis. A total of 1249 procedures for extracranial steno-occlusive lesions were identified from the Japanese Registry of Neuroendovascular Therapy (JR-NET) and JR-NET2. Excluding the cases of carotid lesions (290 cases), endovascular procedures were performed for 471 (37.7%) subclavian artery stenoses, 404 (32.3%) extracranial vertebral artery stenoses, and 38 (3.0%) innominate artery stenoses with a technical success rate of 97.2%. A stent was placed for 783 lesions and percutaneous transluminal angioplasty was performed for 183 lesions. Forty complications were reported in this cohort. Among these, ischemic complications were the most frequent (12 cases). Comparison between JR-NET1 and JR-NET2 demonstrated a marked increase in the number of procedures, a change in the utilization of antiplatelet therapy, and an increased rate of favorable outcome. We conclude that the endovascular treatment for extracranial steno-occlusive lesions is relatively safe. Continuous efforts should be made to reduce the complication rate, and further trials are needed to validate the beneficial effect of this procedure.

Background and Purpose: We conducted a large retrospective survey of the clinical results of carotid artery stenting (CAS) for about 10 years performed by neurointerventionists at 43 Japanese institutions. Hence, the historical perspective of CAS in Japan was demonstrated., Methods: Cases were stratified into three separate periods based on the approval status of devices: the first period, in which off-label CAS was performed using balloon protection; the second period, using a limited number of approved devices under filter protection; the third period, using appropriate protection selected from several different options based on the preoperative evaluation (tailored CAS). Clinical results were retrospectively evaluated. Then 30-day results of each period were examined. The major adverse event (MAE) was defined as stroke, myocardial infarction or death., Results: Between January 2001 and December 2010, a total of 8,092 cases were registered, including 4,072, 1,526 and 2,494 in the first, second and third period, respectively. In the first period, 92 % of CAS was performed under balloon protection. In contrast, 91 % was done under filter protection in the second period. In the third period, various protection methods were used, including balloon (31 %), filter (50 %) and proximal protection (18 %). The rate of MAE at 30 days was 6.1 %, 10.2 % and 3.5 % in the first, second and third periods, respectively, and 6.3 % in all periods combined. The rate of MAE in the third period was significantly lower than that in the first and second periods., Conclusions: The historical paradigm of CAS in Japan was demonstrated. Due to the improvement of devices, increasing experience and appropriate selection of protection, CAS is continuing to evolve into a safer and more efficacious method of stroke prevention.