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Gamma Knife radiosurgery (GKRS) is a frequent treatment choice for patients with small- to moderate-sized vestibular schwannoma (VS). However, pseudoprogression after GKRS is commonly observed, with a reported incidence ranging from 7% to 77%. The wide range of the reported incidence of pseudoprogression reflects the fact that there is no consensus on how it should be diagnosed. The authors present the case of a 66-year-old woman who had a 2.5-cm right-sided VS treated with GKRS in 1997. The first posttreatment MRI obtained 5 months later showed that the tumor volume had increased to 9.7 cm3. The tumor volume increased further and reached its peak 24 months after treatment at 20.9 cm3, which was a 161% increase from pretreatment volume. Thereafter, the tumor shrank gradually and mass effect on the brainstem reduced over time. By 229 months after treatment, the tumor volume was 1.0 cm3, equaling 12.5% of pretreatment tumor volume, or 4.8% of peak tumor volume after treatment. This case demonstrates that if a patient remains asymptomatic despite a dramatic increase in tumor volume after GKRS, observation remains an option, because even a very sizable tumor can shrink with near-complete resolution. Patients undergoing GKRS for VS should be counseled regarding the possibility of pseudoprogression, and followed carefully over time while avoiding premature decisions for surgical removal after treatment.

BACKGROUND: Newer flow diverters are enhanced with antithrombogenic surface modifications like the Pipeline Embolization Device with Shield Technology and the Derivo Embolization Device and are purported to facilitate deployment and reduce ischemic events. PURPOSE: Our aim was to review the safety and efficacy of surface-modified flow diverters in treating patients with cerebral aneurysms. DATA SOURCES: We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses–compliant systematic review and meta-analysis covering 3 major data bases and gray literature between 2014 and 2019. STUDY SELECTION: Two reviewers independently reviewed human studies of surface-modified flow diverters for eligibility based on predetermined criteria. DATA ANALYSIS: The random effects model and Freeman-Tukey arcsine transformation were used to pool efficacy outcomes (technical success, aneurysm occlusion at 6 and 12 months) and safety outcomes (mortality, morbidity, all ischemia, and serious ischemia). Subgroup analysis was performed to compare outcomes between 2 different flow diverters. DATA SYNTHESIS: Eight single-arm case series involving 911 patients and 1060 aneurysms were included. The median follow-up was 8.24 months. Pooled estimate for technical success was 99.6%, while the aneurysm occlusion at 6 and 12 months were 80.5%, and 85.6%, respectively. Pooled estimates for mortality, morbidity, total ischemia, and serious ischemia rates were 0.7%, 6.0%, 6.7%, and 1.8%, respectively. Most studies were of good quality, and no significant heterogeneity was observed. LIMITATIONS: Limitations include a retrospective, observational design in some studies; heterogeneous and underreported antiplatelet therapy; and potential performance and ecologic bias. CONCLUSIONS: Early-to-midterm safety and efficacy for surface-modified flow diverters appear comparable with older devices, especially for small, unruptured anterior circulation aneurysms. Long-term clinical data are required to further corroborate these results.

Background Facial paresis is one of the complications after treatment for vestibular schwannoma (VS). Acupuncture has been used for Bell palsy but not in iatrogenic facial paresis. The objective of this study is to measure the efficacy of using acupuncture for iatrogenic facial nerve palsy and patients' satisfaction. Methods This is a single-center retrospective study with patients from 2007–2019 received treatment for newly diagnosed or recurrent VS. Some patients who suffered facial paresis after surgery had self-initiated acupuncture. All patients who had facial paresis were included. Their facial nerve status before and immediately after surgery, postoperative 6 months and 12 months, were recorded. Those who received acupuncture also answered 6- and 12-month patient satisfaction surveys over the phone. Adverse effects were also assessed. Results There were 123 patients in this period. Of these, 29 patients had iatrogenic facial paresis and 23 of them received acupuncture. There was significant improvement of facial paresis for the acupuncture group compared with the nonacupuncture group at 6 and 12 months. More than 80% of patients who received acupuncture were satisfied. They had motor improvement and experienced less pain and tightness. No adverse effects were reported. Conclusions Acupuncture for postresection VS facial paresis seemed to speed up its recovery. Both patients' recovery and satisfaction were good after acupuncture, and it seemed to be a safe procedure in trained hands.

Sinking skin flap syndrome (SSFS) is a complication among long-term survivors of stroke or traumatic brain injury treated by decompressive craniectomy. The syndrome encompasses a wide spectrum of neurological symptoms including cognitive decline, seizures, speech and sensorimotor deficits. Early cranioplasty appears to improve cerebral perfusion, but the efficacy of cranioplasty in neurocognitive outcome in long-standing SSFS patient is unclear. We report a 64-year-old patient who suffered from traumatic brain injury and underwent decompressive craniectomy 18 years ago. She had chronic SSFS with pre-cranioplasty assessments demonstrating severe neurocognitive impairments which were static over time. After cranioplasty with custom-made polyetheretherketone flap to restore the 264 cm2 skull defect, magnetic resonance perfusion scan with pseudo-continuous arterial spin labelling technique showed a two-fold augmentation of cerebral blood flow in both frontal lobes, as well as areas distal to the sunken skin flap compared to baseline. This is accompanied by improvement of neurocognitive function as assessed by Montreal Cognitive Assessment, Neurobehavioral Cognitive State Examination, and Rivermead Behavioural Memory Test three and six months after cranioplasty. The patient’s quality of life and that of her primary carer also showed improvement. This report describes a case of neurocognitive and global cerebral perfusion improvement after cranioplasty in the setting of prolonged SFSS of 18 years, and adds to the growing body of literature supporting the therapeutic role of cranioplasty beyond purely protective or cosmetic indications. The advantages and clinical utility of pCASL MR perfusion in assessing serial CBF before and after cranioplasty is illustrated.

Background Bypass graft stenosis following extracranial-intracranial bypass surgery carries significant risks for morbidity and mortality. In case of graft failure, treatment options include surgical revision and endovascular intervention. Whereas endovascular intervention following coronary artery bypass is well established, the role of endovascular therapy in cerebral bypass conduits is rarely reported. We present a case of extracranial-intracranial bypass graft stenosis in the early postoperative period that was successfully treated by endovascular angioplasty and stenting. Case Description A middle-aged patient presented with a malignant skull base tumor with internal carotid artery invasion. Extracranial-intracranial bypass surgery was performed for flow preservation before tumor removal. Autologous radial artery was used as the bypass graft conduit. Symptomatic graft stenosis was encountered in the immediate postoperative period. Treatments in the form of intra-arterial vasodilator infusion and balloon angioplasty led to only minor flow improvement. The narrowing was eventually salvaged by endovascular stenting. Good clinical and radiologic outcomes were achieved at 6-month follow-up. Conclusions Endovascular intervention is a feasible treatment option in management of graft stenosis after cerebral revascularization surgery. Our case adds evidence to the safety and role of endovascular intervention in early cerebral bypass conduit failure. In addition, endovascular stenting can be considered as a salvage option for cases that are refractory to angioplasty.

Background Fall with head injury is a pervasive challenge, especially in the aging population. Contributing factors for mortality include the development of cerebral contusions and delayed traumatic intracerebral hematoma. Currently, there is no established specific treatment for these conditions. Object This study aimed to investigate the impact of independent factors on the mortality rate of traumatic brain injury with contusions or traumatic subarachnoid hemorrhage. Methods Data were collected from consecutive patients admitted for cerebral contusions or traumatic subarachnoid hemorrhage at an academic trauma center from 2010 to 2016. The primary outcome was the 30-day mortality rate. Independent factors for analysis included patient factors and treatment modalities. Univariate and multivariate analyses were conducted to identify independent factors related to mortality. Secondary outcomes included thromboembolic complication rates associated with the use of tranexamic acid. Results In total, 651 consecutive patients were identified. For the patient factors, low Glasgow Coma Scale on admission, history of renal impairment, and use of warfarin were identified as independent factors associated with higher mortality from univariate and multivariate analyses. For the treatment modalities, univariate analysis identified tranexamic acid as an independent factor associated with lower mortality (P = 0.021). Thromboembolic events were comparable in patients with or without tranexamic acid. Conclusion Tranexamic acid was identified by univariate analysis as an independent factor associated with lower mortality in cerebral contusions or traumatic subarachnoid hemorrhage. Further prospective studies are needed to validate this finding.

Recent studies in Caucasians with transient ischaemic attack or ischaemic stroke have demonstrated significant age-specific associations between cerebral small vessel disease (SVD) burden on magnetic resonance imaging and renal impairment. We aimed to validate these findings in a large cohort of Chinese with ischaemic stroke.In 959 Chinese with ischaemic stroke who received a brain magnetic resonance imaging at the University of Hong Kong, we determined the age-specific associations of renal impairment (glomerular filtration rate60 mL/min/1.73 mAlthough renal impairment was associated with the SVD score in univariate analysis in all patients (odds ratio 1.61, 95% confidence interval 1.24-2.09, P.0001), these associations were attenuated after adjusting for age and sex (P = .38). Similar findings were noted in patients with ischaemic stroke due to SVD and non-SVD subtypes. However, in 222 of 959 patients aged60, renal impairment was independently associated with an increasing microbleed (adjusted odds ratio 6.82, 2.26-20.59), subcortical (4.97, 1.62-15.24) periventricular white matter hyperintensity (3.96, 1.08-14.51) and global SVD burden (3.41, 1.16-10.04; all P.05) even after adjusting for age, sex, and vascular risk factors. Nevertheless, there were no associations between renal impairment and individual neuroimaging markers of SVD nor with the SVD score in patients aged ≥60 after adjusting for age and sex (all P.05).In Chinese with ischaemic stroke, renal impairment was independently associated with microbleed, white matter hyperintensity and global SVD burden in individuals aged60, but not in those aged ≥60, suggesting that there may be shared susceptibilities to premature systemic disease.

Background and objectivePulsatile tinnitus (PT) can be debilitating and lead to significant morbidity. Cerebral venous sinus lesions, such as venous sinus stenosis, diverticula, and high-riding jugular bulb, are uncommon causes of PT, for which there is no standard treatment. Endovascular interventions have shown promising results for PT secondary to idiopathic intracranial hypertension, and may be a valid therapeutic option for isolated venous PT.MethodsWe conducted a systematic literature review on the outcome and safety of endovascular treatment for patients with isolated, debilitating venous PT. The venous lesion characteristics, endovascular techniques, complications, and clinical outcomes were assessed. In addition, an illustrative case of endovascular stenting for PT caused by venous sinus stenosis was included.ResultsA total of 41 patients (90.2% female) from 26 papers were included. The median age was 46 years (IQR 23; range 25–72 years). Focal venous sinus stenosis (20 patients) and sinus diverticula (14 patients) were the most common culprit lesions. Endovascular treatment included venous sinus stenting in 35 patients, 11 of whom had adjuvant coil embolization, and coil embolization alone in six patients. Complete resolution of the tinnitus was achieved in 95.1% of patients. There was one complication of cerebellar infarct, and no procedure-related mortality.ConclusionsIn patients with debilitating PT secondary to venous sinus lesions, endovascular treatment by stenting and/or coil embolization appears to be safe and effective. Prospective randomized studies with objective outcome assessments are needed to confirm the treatment benefits.

Objective Intracranial dural arteriovenous fistulas (DAVFs) can manifest with a reversible form of dementia and parkinsonism that may be related to medullary venous hypertension and impaired cortical venous drainage. We report a consecutive case series of patients with DAVFs who presented with cognitive decline and report angioarchitecture and outcomes of treatment. Methods From a prospectively collected database of 389 cranial DAVFs, we identified patients who presented with progressive dementia. Data collected included demographic characteristics, other presenting symptoms, fistula location and type, preoperative and postoperative imaging findings, and treatment outcomes. Descriptive statistics were reported. Results Of 389 patients with DAVF, 6 patients with progressive dementia (1.4%) were identified. All patients were male. Mean patient age was 68.6 years. Four patients had superior sagittal sinus DAVFs, 1 patient had a tentorial DAVF, and 1 patient had a transverse sinus DAVF. All patients had evidence of medullary venous hypertension on imaging with either reflux and arterialization of the transmedullary veins or venous congestion of the transmedullary veins. All patients underwent endovascular treatment and had reversal of dementia-related symptoms after a mean follow-up of 6.2 months. Conclusions Cognitive decline is a rare but reversible manifestation of DAVFs that have impaired venous drainage of the transmedullary veins and associated medullary venous hypertension.

The hyperdense middle cerebral artery sign (HMCAS) representing a thromboembolus has been declared as a vital CT finding for intravascular thrombus in the diagnosis of acute ischemia stroke. Early recognition of HMCAS can assist in patient triage and subsequent thrombolysis or thrombectomy treatment. A total of 624 annotated head non-contrast-enhanced CT (NCCT) image scans were retrospectively collected from multiple public hospitals in Hong Kong. In this study, we present a deep Dissimilar-Siamese-U-Net (DSU-Net) that is able to precisely segment the lesions by integrating Siamese and U-Net architectures. The proposed framework consists of twin sub-networks that allow inputs of left and right hemispheres in head NCCT images separately. The proposed Dissimilar block fully explores the feature representation of the differences between the bilateral hemispheres. Ablation studies were carried out to validate the performance of various components of the proposed DSU-Net. Our findings reveal that the proposed DSU-Net provides a novel approach for HMCAS automatic segmentation and it outperforms the baseline U-Net and many state-of-the-art models for clinical practice.

This was followed by an interactive discussion of investigation and management plan. Appropriate radiological imaging such as an MRI brain scan was shown to the group using the “share‐screen” function. Other clinical information such as laboratory results can likewise be displayed. The session was completed after thorough discussion on the appropriate treatment plan with respect to the patient’s scenario.

Background and Purpose: The current coronavirus disease 2019 (COVID-19) pandemic represents a global public health crisis, disrupting emergency healthcare services. We determined whether COVID-19 has resulted in delays in stroke presentation and affected the delivery of acute stroke services in a comprehensive stroke center in Hong Kong. Methods: We retrospectively reviewed all patients with transient ischemic attack and stroke admitted via the acute stroke pathway of Queen Mary Hospital, Hong Kong, during the first 60 days since the first diagnosed COVID-19 case in Hong Kong (COVID-19: January 23, 2020–March 24, 2020). We compared the stroke onset to hospital arrival (onset-to-door) time and timings of inpatient stroke pathways with patients admitted during the same period in 2019 (pre–COVID-19: January 23, 2019–March 24, 2019). Results: Seventy-three patients in COVID-19 were compared with 89 patients in pre–COVID-19. There were no significant differences in age, sex, vascular risk factors, nor stroke severity between the 2 groups ( P >0.05). The median stroke onset-to-door time was ≈1-hour longer in COVID-19 compared with pre–COVID-19 (154 versus 95 minutes, P =0.12), and the proportion of individuals with onset-to-door time within 4.5 hours was significantly lower (55% versus 72%, P =0.024). Significantly fewer cases of transient ischemic attack presented to the hospital during COVID-19 (4% versus 16%, P =0.016), despite no increase in referrals to the transient ischemic attack clinic. Inpatient stroke pathways and treatment time metrics nevertheless did not differ between the 2 groups ( P >0.05 for all comparisons). Conclusions: During the early containment phase of COVID-19, we noted a prolongation in stroke onset to hospital arrival time and a significant reduction in individuals arriving at the hospital within 4.5 hours and presenting with transient ischemic attack. Public education about stroke should continue to be reinforced during the COVID-19 pandemic.

One of the treatment options for long segment common carotid artery (CCA) occlusion is bypass surgery with different combinations of donors and receipts. Using vertebral artery (VA) as the donor for CCA occlusion was uncommonly reported. The reported cases were using jump graft to connect V3 segment of VA to either CCA or ICA. We describe our patient using V2 segment as the donor for VA-CCA bypass as treatment for CCA occlusion. Our patient was a 51 years old gentleman with Marfan syndrome and had multiple operations that included total arch replacement. He presented with sudden onset of spontaneous right frontal subarachnoid haemorrhage and repeated episodes of TIA with left upper limb numbness. CTA showed occluded right CCA and anastomosis between branches from subclavian artery and occipital artery. CT perfusion showed hypoperfusion of right hemisphere. To avoid damaging the anastomosis at subclavian artery and occipital artery, we decided for V2-RAG (radial artery graft)-CCA bypass. It was done by exposing the V2 segment at C4/5 level, performing end-to-side anastomoses at V2-RAG and RAG-CCA junctions where the RAG was underneath the internal jugular vein. Patient had no new deficits after surgery and no more TIAs. CTA performed one week after surgery showed patent RAG. In conclusion, using V2 for VA-CCA bypass is technically feasible and may have theoretical advantages over using V3. V2-CCA bypass is an option for CCA occlusion in very selected patients.

Background The detection of large vessel occlusion (LVO) plays a critical role in the diagnosis and treatment of acute ischemic stroke (AIS). Identifying LVO in the pre-hospital setting or early stage of hospitalization would increase the patients' chance of receiving appropriate reperfusion therapy and thereby improve neurological recovery. Methods To enable rapid identification of LVO, we established an automated evaluation system based on all recorded AIS patients in Hong Kong Hospital Authority's hospitals in 2016. The 300 study samples were randomly selected based on a disproportionate sampling plan within the integrated electronic health record system, and then separated into a group of 200 patients for model training, and another group of 100 patients for model performance evaluation. The evaluation system contained three hierarchical models based on patients' demographic data, clinical data and non-contrast CT (NCCT) scans. The first two levels of modeling utilized structured demographic and clinical data, while the third level involved additional NCCT imaging features obtained from deep learning model. All three levels' modeling adopted multiple machine learning techniques, including logistic regression, random forest, support vector machine (SVM), and eXtreme Gradient Boosting (XGboost). The optimal cut-off for the likelihood of LVO was determined by the maximal Youden index based on 10-fold cross-validation. Comparisons of performance on the testing group were made between these techniques. Results Among the 300 patients, there were 160 women and 140 men aged from 27 to 104 years (mean 76.0 with standard deviation 13.4). LVO was present in 130 (43.3%) patients. Together with clinical and imaging features, the XGBoost model at the third level of evaluation achieved the best model performance on testing group. The Youden index, accuracy, sensitivity, specificity, F1 score, and area under the curve (AUC) were 0.638, 0.800, 0.953, 0.684, 0.804, and 0.847, respectively. Conclusion To the best of our knowledge, this is the first study combining both structured clinical data with non-structured NCCT imaging data for the diagnosis of LVO in the acute setting, with superior performance compared to previously reported approaches. Our system is capable of automatically providing preliminary evaluations at different pre-hospital stages for potential AIS patients.

There is increasing use of automated computed tomography perfusion (CTP) to aid thrombectomy decision in emergent large vessel occlusion. It is important to understand the performance of these software packages in predicting ischemic core and tissue-at-risk in the real-world setting. The aim of this study was to evaluate whether ischemic core on non-contrast CT (NCCT) and automated CTP correspond and predict infarct extent after thrombectomy for ischemic stroke. Consecutive patients with acute anterior circulation large vessel occlusion undergoing successful thrombectomy (TICI 2b/3) were studied. All patients had baseline CT, CTP with RAPID post-processing software (RAPID-CTP), and post-thrombectomy 24 h CT. Ischemic cores were assessed by two blinded raters independently using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) on each modality. The interrater agreement for ASPECTS, and correlation between baseline CT-ASPECTS, RAPID-CTP-ASPECTS, and 24h CT-ASPECTS were calculated. A total of 86 patients with a mean age of 70.3 years (SD 16.5) were studied. The median baseline CT-ASPECTS was 9.5 (interquartile range, IQR 8–10), median RAPID-CTP-ASPECTS was 9 (IQR 8–10), and mean RAPID-CTP-ischemic core volume was 14.4 ml (SD 27.9 ml). The mean mismatch volume (difference of Tmax > 6s and cerebral blood flow (CBF)

Advanced morphology analysis and image-based hemodynamic simulations are increasingly used to assess the rupture risk of intracranial aneurysms (IAs). However, the accuracy of those results strongly depends on the quality of the vessel wall segmentation. To evaluate state-of-the-art segmentation approaches, the Multiple Aneurysms AnaTomy CHallenge (MATCH) was announced. Participants carried out segmentation in three anonymized 3D DSA datasets (left and right anterior, posterior circulation) of a patient harboring five IAs. Qualitative and quantitative inter-group comparisons were carried out with respect to aneurysm volumes and ostia. Further, over- and undersegmentation were evaluated based on highly resolved 2D images. Finally, clinically relevant morphological parameters were calculated. Based on the contributions of 26 participating groups, the findings reveal that no consensus regarding segmentation software or underlying algorithms exists. Qualitative similarity of the aneurysm representations was obtained. However, inter-group differences occurred regarding the luminal surface quality, number of vessel branches considered, aneurysm volumes (up to 20%) and ostium surface areas (up to 30%). Further, a systematic oversegmentation of the 3D surfaces was observed with a difference of approximately 10% to the highly resolved 2D reference image. Particularly, the neck of the ruptured aneurysm was overrepresented by all groups except for one. Finally, morphology parameters (e.g., undulation and non-sphericity) varied up to 25%. MATCH provides an overview of segmentation methodologies for IAs and highlights the variability of surface reconstruction. Further, the study emphasizes the need for careful processing of initial segmentation results for a realistic assessment of clinically relevant morphological parameters.

Intracranial aneurysm can lead to hemorrhagic stroke upon rupture. Deployment of flow diverters can restrict the blood flow into aneurysm and mitigate the rupture risk. Computational fluid dynamics (CFD) and ultrasonography with pulse-wave and color Doppler ultrasound measurements were employed jointly to investigate the complex flow pattern in cerebral aneurysms, both before and after the deployment of flow diverters. Patient-specific configurations of both bifurcation and side-wall aneurysms were selected. The effect of downstream flow resistance was investigated by adjusting the volume flow rate and pressure at the outlet vessels computationally and experimentally. Velocity profiles in the aneurysm measured from ultrasonography showed good agreement with those from computer simulations. The discrepancy in velocity between the computational and experimental sets of data is less than 10%. The downstream resistance can alter the volume flux into a bifurcation aneurysm with a flow diverter deployed by 236%, while the corresponding value of a side-wall aneurysm is negligible. The vorticity of the aneurysmal flow was reduced by more than 80% in both cases after stenting. This study demonstrated that careful investigation of downstream flow resistance of a bifurcation aneurysm is essential to provide an accurate assessment of the aneurysmal flow dynamics after flow diverter deployment.

Background and purposeThoracolumbar and sacral spinal epidural arteriovenous fistulas (SEDAVFs) are an increasingly recognized form of spinal vascular malformation. The purpose of this study was to perform a systematic review of the demographics, clinical presentation and treatment results of thoracolumbar SEDAVFs.Materials and methodsPubmed, Scopus and Web of Science databases were searched from January 2000 to January 2018 for articles on treatment of SEDAVFs. Pooled data of individual patients were analyzed for demographic and clinical features of SEDAVFs as well as treatment outcomes.ResultsThere were 125 patients from 11 studies included. Mean age was 63.5 years. There was a male sex predilection (69.6%). Sensory symptoms including pain or numbness were the most frequently presenting symptoms. Fistula location was the lumbosacral spine in 79.2% and the thoracic spine in 20.8%. Involvement of intradural venous drainage was more common than extradural venous drainage only (89.6% vs 10.4%). Of the 123 treated patients, endovascular therapy was performed in 67.5% of patients, microsurgery in 23.6%, and combined treatment in 8.9%. The overall complete obliteration rate was 83.5% and did not differ between groups. Clinical symptoms improved in 70.7% of patients, were stable in 25%, and worsened in 1.7% with no difference between treatment modalities.ConclusionsThoracic and lumbosacral SEDAVFs often present with symptoms secondary to congestive myelopathy or compressive symptoms. Both endovascular and microsurgical treatments were associated with high obliteration rates and good clinical outcomes.

Background Nickel is the most common metal allergen and predominantly affects women. It is also the ubiquitous component in the alloys used to manufacture intracranial devices for aneurysm treatments, including aneurysm clips, self-expanding stents, flow-diverting stents, and endosaccular occlusion devices. Adverse events related to nickel allergy after deployment of such devices are uncommon but can be severe, resulting in dilemmas in the choice of treatment strategies and devices in managing nickel-sensitive patients with intracranial aneurysms. Methods A literature search was performed in accordance with the PRISMA guidelines to identify studies reporting on nickel-related adverse events in patients being treated for cerebral aneurysm. The materials of the culprit devices, clinical presentation, histological features, and treatments were reviewed. Clinical considerations and management options for nickel allergy patients were evaluated. Results Nickel is a major component of the cobalt alloy used in aneurysm clips and also of nitinol, which is commonly used in flow diverters and intracranial stents. Our literature review identified 9 articles reporting 10 unique cases of nickel-related adverse events after aneurysm treatment. Five of the cases occurred after aneurysm clipping, and the other 5 were attributed to endovascular devices. Two patients presented with dermatologic manifestations and 8 with neurologic manifestations, including cerebral edema and cerebritis. Conclusions Neurologic complications related to nickel in cerebral aneurysm treatments are rare but remain concern owing to the high prevalence of nickel allergy in the population. Surgeons and interventionists should consider the metal allergy history and its potential clinical significance in managing nickel-allergic patients with aneurysms.

The rupture of intracranial aneurysms might lead to permanent disability or even death. One possible endovascular treatment is the deployment of flow diverters (FDs), which reduces flow into the sac and promotes thrombosis. Computational fluid dynamics simulations were used to assess the flow patterns and dynamics. The concept of energy loss, as a measure of necessary work done to overcome flow resistance, was utilized to correlate with clinical outcome. If a surgical operation is successful, the flow would be diverted to a shorter path and energy loss should be reduced. Conversely, persistent flow in the sac, associated with treatment failure, would display an increased energy loss as blood is then squeezed through the stent pores. Four illustrative clinical cases, involving both bifurcation and sidewall aneurysms, were selected. To reduce the numerical complexity, earlier works in the literature had used a porous medium approximation for the FDs. Here, the FD was simulated explicitly as a virtual (or computer-generated) stent, which would likely provide a more accurate description. Furthermore, quantitative comparisons between the approaches of virtual stenting and a porous medium with typical parameters were conducted by examining the effective flow influx into the aneurysm.

Objectives To compare surgical outcome both radiologically and clinically after interventions for patients with Moyamoya disease. Methods This retrospective observational study included 25 patients who were treated surgically for Moyamoya disease in the past 14 years. Clinical outcomes were analyzed by subgroups stratified by age, disease presentation, and surgical intervention. Serial postoperative brain computed tomography perfusion records were analyzed with respect to the cerebral blood flow and cerebrovascular reserve capacity (CVRC) of the middle cerebral artery territory. Changes in both the intervention ( n = 23) and nonintervtion ( n = 9) cerebral hemispheres were compared. Results All children treated by synangiosis ( n = 9), all adults receiving synangiosis ( n = 5), and 88.9% of adults undergoing bypass ( n = 9) had no neurologic deterioration, with a duration of at least 50.6 months, 85.7 months, and 27.7 months, respectively. Radiologically, CVRC improved more markedly after bypass surgery than synangiosis, particularly 12–24 months postoperatively (51.1% vs. −2.86%). The hemispheres that did not undergo intervention showed similar improvement in cerebral blood flow over time compared with the hemispheres that did undergo intervention, after surgery was performed. Conclusions Bypass surgery improved CVRC greater than synangiosis, which may correlate with decreased future stroke risks. The decision for bypass is to be balanced with a greater risk of postoperative neurologic deterioration in adults after this procedure. The hemisphere that did not undergo intervention also appeared to benefit from surgery performed on the contralateral brain.

We report a rare delayed complication of de novo pseudoaneurysm formation and rupture after stereotactic radiotherapy for cerebral arteriovenous malformation. The patient presented with intracerebral haemorrhage due to rupture of a pseudoaneurysm in the previously irradiated field, which was excised for histological examination. The literature was reviewed for similar cases.

Cerebral hyperperfusion syndrome is a serious complication of endovascular angioplasty and stent placement for long-standing intracranial stenosis, resulting in neurologic dysfunction, seizure, or reperfusion hemorrhage. Rigorous control of blood pressure is commonly used in the perioperative period to prevent cerebral hyperperfusion syndrome, but the optimal blood pressure is often arbitrary. We describe the angiographic features that reflect impaired cerebral autoregulation and microvascular transit abnormality, which may be used to gauge the optimal blood pressure parameters in the immediate postintervention period for prevention of cerebral hyperperfusion syndrome.

Background Ischemic stroke due to large vessel occlusion can be effectively treated with thrombectomy but access to this treatment is limited in many parts of the world. Local incidence of large vessel occlusion is critical in determining the development of thrombectomy service, but reliable data from Asian countries are lacking. Aims We performed a population-based study to estimate the burden of large vessel occlusion and the service gap for thrombectomy in Hong Kong. Methods All acute ischemic stroke patients admitted in 2016 to the public healthcare system, which provided 90% of the emergency healthcare in the city, was identified from the Hong Kong Hospital Authority’s central electronic database. The diagnosis of large vessel occlusion was retrospectively verified by two independent cerebrovascular specialists in a randomly sampled cohort based on clinical and neuroimaging data. The incidence of large vessel occlusion in the population was estimated through weighting the sample results and compared with the thrombectomy data in the same period. Results There were 6859 acute ischemic stroke patients treated in the public health system in 2016. Amongst the 300 patients randomly sampled according to diagnosis coding, 130 suffered from anterior circulation large vessel occlusion. This translated to 918 patients (95% CI 653–1180) and 13.3% of all ischemic stroke patients. The estimated incidence of anterior circulation large vessel occlusion was 12.5 per 100,000 persons per year (95% CI 11.7–13.4). Large vessel occlusion stroke patients were more commonly female than male (67.4% vs. 31.6%, p = 0.003), and were older than non-large vessel occlusion stroke patients (mean of 80.5 years vs. 71.4 years, p = Conclusion The estimated incidence of anterior circulation large vessel occlusion in the Hong Kong Chinese population is lower than that in the West. There is however a substantial service gap for endovascular thrombectomy with less than 10% of large vessel occlusion patients receiving thrombectomy.

PurposeAssessing the rupture probability of intracranial aneurysms (IAs) remains challenging. Therefore, hemodynamic simulations are increasingly applied toward supporting physicians during treatment planning. However, due to several assumptions, the clinical acceptance of these methods remains limited.MethodsTo provide an overview of state-of-the-art blood flow simulation capabilities, the Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH) was conducted. Seventeen research groups from all over the world performed segmentations and hemodynamic simulations to identify the ruptured aneurysm in a patient harboring five IAs. Although simulation setups revealed good similarity, clear differences exist with respect to the analysis of aneurysm shape and blood flow results. Most groups (12/71%) included morphological and hemodynamic parameters in their analysis, with aspect ratio and wall shear stress as the most popular candidates, respectively.ResultsThe majority of groups (7/41%) selected the largest aneurysm as being the ruptured one. Four (24%) of the participating groups were able to correctly select the ruptured aneurysm, while three groups (18%) ranked the ruptured aneurysm as the second most probable. Successful selections were based on the integration of clinically relevant information such as the aneurysm site, as well as advanced rupture probability models considering multiple parameters. Additionally, flow characteristics such as the quantification of inflow jets and the identification of multiple vortices led to correct predictions.ConclusionsMATCH compares state-of-the-art image-based blood flow simulation approaches to assess the rupture risk of IAs. Furthermore, this challenge highlights the importance of multivariate analyses by combining clinically relevant metadata with advanced morphological and hemodynamic quantification.

Background: Tranexamic acid (TA) administration in aneurysmal subarachnoid hemorrhage (SAH) within the first 24 hours may reduce the incidence of early aneurysmal rebleeding. However, this is also the potential for an increased risk of delayed cerebral ischemia if TA is administered for more than 72 hours following the initial aneurysmal rupture. Methods: In the ultra-early tranexamic acid after subarachnoid hemorrhage randomized controlled trial by Post et al., patients were randomized to receive TA within the first 24 hours, or until start of aneurysm treatment. These results were compared to a matched control group. Results: Ultra-early administration (≤24 h) of TA reduced the incidence of rebleeding, and did not alter the incidence of delayed cerebral ischemia and/or extracranial thrombosis. Further, no significant differences were noted between the TA group and control arm in the incidence of good (modified Rankin scores 0-3) clinical outcomes at 6 months. Conclusion: Ultra-early administration of TA (≤24 h) resulted in a lower rate of recurrent hemorrhage, without increasing the incidence of delayed cerebral ischemia in SAH patients.

A middle-aged lady in good health presented right abducens nerve palsy. Magnetic resonance imaging (MRI) of the brain showed bilateral cavernous ICA aneurysms. The left aneurysm measured 9 × 7 mm whereas the right aneurysm measured 22 × 15 mm, with mass effect on the cavernous sinus, explaining her symptoms (Fig. 1). Both were wide-neck aneurysms and were treated with PED alone sequentially, 3 months apart. She was loaded with Aspirin 300 mg and Clopidogrel 300 mg before treatment, with Aspirin continuing for 6 months and Clopidogrel for 3 months afterwards. There were no procedural complications. Digital subtraction angiogram at 1 year showed that the left aneurysm was completely occluded, whereas the right aneurysm had partially thrombosed but with a persistent filling. The right aneurysm persisted on CT angiogram at 2 years but with significant shrinkage and finally occluded at a 3-year follow-up (Fig. 2). The patient’s diplopia gradually improved after 3 years.

BACKGROUND AND PURPOSE: A number of studies have demonstrated the existence of segmental vascular disorders affecting soft tissues of the head and neck along with the intracranial vasculature. The purpose of this study was to determine whether there is an association between cerebral developmental venous anomalies and venous malformations of the face, head, and neck. MATERIALS AND METHODS: A consecutive series of patients with head and neck venous malformations who underwent MR imaging of the brain with postcontrast T1- or T2*-weighted imaging were included. Developmental venous anomaly prevalence in this patient population was compared with an age- and sex-matched control group without venous malformations at a ratio of 1:2. All images were interpreted by 2 neuroradiologists. Data were collected on venous malformation location, developmental venous anomaly location, developmental venous anomaly drainage pattern, and metameric location of venous malformations and developmental venous anomalies. Categoric variables were compared using χ2 tests. RESULTS: Forty-two patients with venous malformations were included. The mean age was 38.1 ± 11.1 years, and 78.6% of patients were female. The prevalence of developmental venous anomalies in this patient population was 28.6%. The control population of 84 patients had a mean age of 40.0 ± 5.9 years, and 78.6% of patients were female. The prevalence of developmental venous anomalies in this patient population was 9.5% (P = .01). In 83.3% of cases, developmental venous anomalies were ipsilateral to the venous malformation, and in 75% of cases, they involved the same metamere. CONCLUSIONS: Our case-control study demonstrated a significant association between brain developmental venous anomalies and superficial venous malformations. These findings suggest that there may be a similar pathophysiologic origin for these 2 entities.

Objectives Intracranial atherosclerosis related large vessel occlusions (ICAS-O) are challenging to diagnose and manage. The degree of intracranial carotid artery calcification may assist pre-thrombectomy diagnosis of ICAS and guide treatment strategy. The aim of the study is to determine if intracranial carotid calcification is associated with ICAS-O. Patients and methods Consecutive large vessel occlusion patients who underwent thrombectomy from 2006 to 2017 were retrospectively studied. Patients were classified into ICAS-O if pre-existing atherosclerotic lesion was identified as the etiology for large vessel occlusion during the thrombectomy. The degree of intracranial carotid artery calcification (ICAC), technical and clinical outcomes of ICAS-O was compared with non-ICAS-O patients. Results In a retrospective cohort study of 64 thrombectomy patients, ICAS-O accounted for 14.1% of cases and was associated with higher degree of carotid calcification (mean Woodcock scale 2.8 vs 1.6, p = 0.044), need of stent-retreiver rescue (55.6% vs 5.5%, p = 0.001), and adjuvant stenting or angioplasty (33.3% vs 0%, p = 0.002) compared with non-ICAS-O. Conclusion The severity of ICAC may be associated with ICAS-O as the underlying etiology amongst thrombectomy patients. Compared with large vessel occlusion of other causes, ICAS-O was associated with more failure of aspiration and a higher need of adjuvant stenting and angioplasty.

Sacral insufficiency fractures result in significant morbidity, and percutaneous sacroplasty has emerged as a promising technique for their treatment. We present a technical note regarding our method of treating these fractures using a "single-needle" lateral technique with a combination of conebeam CT and biplane fluoroscopy. We treated 10 patients, in whom the median Visual Analog Scale pain score decreased from 7.0 to 0 (P < .001). We concluded that single-needle sacroplasty is feasible and safe using this technique.

BackgroundStenting of the intracranial venous sinuses is used as a treatment in certain cases of idiopathic intracranial hypertension (IIH). Interest in, and experience of, this technique is growing, particularly in recent years. We sought to provide an updated systematic review and meta-analysis of the use of venous stenting in these patients, examining clinical outcomes.MethodsA literature search of venous stenting in IIH patients was performed. Using random-effects meta-analysis, we evaluated the following outcomes: clinical resolution of papilledema; headaches and pulsatile tinnitus; recurrence of symptoms after stenting; and complications.ResultsTwenty articles from 18 different centers were included. In a total of 474 patients. 418 were female (88%). The mean age of the patients was 35, while the mean body mass index (BMI) was 35 kg/m2. Median follow-up was 18 months. The overall rate of improvement in papilloedema was 93.7% (95% CI 90.5% to 96.9%), while the overall rate of improvement or resolution of headache was 79.6% (95% CI 73.3% to 85.9%). Pulsatile tinnitus resolved in 90.3% (95% CI 83.8% to 96.70%), while the overall rate of recurrence of IIH symptoms after stenting was 9.8% (95% CI 6.7% to 13%). The rate of major complications was 1.9% (95% CI 0.07% to 3.1%).ConclusionsVenous sinus stenting in patients with IIH who are refractory to medical therapy appears to have an excellent safety profile and is associated with significant improvements in headaches, pulsatile tinnitus, and papilledema.

Background and purpose We calculated the PHASES and ELAPSS scores for a large cohort of ruptured intracranial aneurysms (RIA) in order to determine whether these RIA would have been pre-emptively treated or closely followed-up should they have been detected prior to rupture. Materials and methods We retrospectively reviewed a consecutive series of RIA over a 20 year period. The primary outcome of this study was the PHASES score of each ruptured aneurysm included. Secondary outcomes were ELAPSS score and other risk factors for aneurysmal subarachnoid haemorrhage including; aneurysm location, aneurysm size, aneurysm morphology, smoking and hypertension history, personal and family history of subarachnoid haemorrhage. Multiplicity of cerebral aneurysms was recorded. Descriptive statistics are reported. Results 700 consecutive ruptured aneurysms were included. Mean age at rupture was 56 (+/-13.5) years. Mean aneurysm size was 5.9 (+/-2.5) mm. Most common locations of ruptured aneurysms was the anterior cerebral/communicating artery (39%), posterior communicating artery (21%), middle cerebral artery (16%) and basilar terminus (7%). Mean PHASES score was 5.3 (+/-2.5) and 17% of the RIA had a PHASES score of 3 or less. Mean ELAPSS score was 13.89 (+/-7.05) and over half of the RIA included had a low risk of future growth. Conclusions A reasonable percentage of ruptured aneurysms have a low calculated PHASES score and these aneurysms may have been managed conservatively should they have presented incidentally prior to rupture. The majority of ruptured aneurysms also had a low ELAPSS score and were at low risk of future growth. The use PHASES score and ELAPSS score alone when making treatment decisions could result in many aneurysms being treated conservatively or undergoing remote surveillance despite rupture potential.

Cerebral venous sinus thrombosis is an uncommon cause of stroke with high morbidity and mortality rates from venous infarction, intracranial hemorrhage, and extensive cerebral edema. Endovascular treatment with various devices has been proposed as a salvage treatment when standard medical treatment with systemic anticoagulation is ineffective, especially in long segment dural sinus thrombosis. We describe our technique of transvenous endovascular aspiration thrombectomy with large bore thrombectomy catheters, followed by placement of microcatheter for local thrombolytic infusion at the site of thrombosis. We report a retrospective study of angiographic and clinical outcome of six consecutive patients treated with this approach. Endovascular aspiration thrombectomy with large bore catheters followed by continuous local thrombolytic infusion appeared to be a safe and effective salvage treatment for selected patients with cerebral dural venous sinus thrombosis refractory to medical treatment.

Stenting and angioplasty of the vertebral artery (VA) is used to treat symptomatic stenosis but the long-term outcomes and complications are unclear. This study evaluated the long-term clinical outcomes and procedure-related complications in patients who underwent extracranial VA stenting and angioplasty, in particular the risks of in-stent restenosis (ISR) and stent fracture. This was a retrospective review of consecutive patients suffering from symptomatic extracranial VA stenosis who were treated with balloon-expandable bare metal stents. The clinical and angiographical outcomes were reviewed for procedural complications, recurrent stroke, ISR and stent fracture. In this study 22 patients (17 male, 5 female) with a mean age of 63.4 years (SD 9.1 years) were included. The median follow-up was 56 months (interquartile range IQR 51.8 months). There were no periprocedural complications. The cumulative ISR risk was 45% with 6 cases detected at 1 year and 3 cases detected at 3 years post operation. The cumulative stent fracture rate at 1 year, 3 years, 5 years and the entire follow-up period were 5%, 15%, 25%, and 30%, respectively. Posterior circulation stroke occurred in 1 patient (4.5%), and 3 patients died of non-cerebrovascular causes during follow-up. Of the patients 2 with ISR and stent fracture required additional treatment. The long-term ISR and stent fracture risks were high in extracranial VA stenosis treated with balloon-expandable bare metal stents. The risk of stent fracture increased over time during the follow-up period. Further studies should be conducted to clarify the long-term safety and efficacy of extracranial VA stenting.

OBJECTIVEHydrocephalus with a blocked ventriculoperitoneal (VP) shunt is a life-threatening condition. Emergency endoscopic third ventriculostomy (ETV) is a potential treatment option. The aim of the study was to identify independent risk factors associated with failure of ETV in treating patients with blocked shunts.METHODSThe authors retrospectively reviewed data from consecutive patients admitted for blocked shunt treated by ETV during the study period from 2000 to 2016. Univariate and multivariate analyses were performed to identify independent factors associated with failed ETV for blocked shunts, such as age, sex, history of CNS infection, number of previous shunt revisions, operations performed as an emergency or elective, number of specialists, and other factors.RESULTSIn total, 121 patients underwent ETV during the study period. Of these, 31 patients (25.6%) had ETV for treatment of a blocked shunt. In 25 (80.6%) of 31 ETV was performed as an emergency procedure. There was no significant difference in the success rate of ETV depending on whether it was performed as an emergency procedure (64% [16/25]) or an elective procedure (66.7% [4/6]; OR 0.062, 95% CI 0.001–2.708; p = 0.149). Univariate and multivariate analyses identified that history of a CNS infection was an independent risk factor for failure of ETV in treating patients with a blocked shunt (OR 0.030, 95% CI 0.001–0.888; p = 0.043).CONCLUSIONSEmergency ETV had a comparable success rate as elective ETV. A history of CNS infection is an independent predictor of ETV failure in treating patients with blocked shunts.

Background Iatrogenic cerebral venous sinus injury and occlusion may occur during resection of parasagittal meningioma and lateral skull base surgery. The former involves the superior sagittal sinus, and direct surgical repair is associated with good results. Outcome of direct repair of transverse–sigmoid sinus injury is less clear. We present a patient with iatrogenic sigmoid sinus injury in whom direct repair was complicated by subsequent thrombosis that was successfully salvaged by combined endovascular mechanical and chemical thrombolysis. Case Description A 60-year-old man with left tentorial atypical meningioma had disease recurrence after 3 excisions. Angiography revealed that the straight sinus and torcular and bilateral transverse sinuses were occluded. He underwent a fourth craniotomy with inadvertent occlusion of the transverse–sigmoid sinus junction. Direct surgical repair was done but was complicated by thrombosis. Mechanical endovenous thrombectomy was done followed by continuous urokinase infusion for 1 week. Digital subtraction angiography performed 7 days after endovascular treatment showed improved venous drainage through the left transverse–sigmoid sinus junction. The patient was ambulatory and fully independent, with no new neurologic deficit. Conclusions This case emphasizes the need to preserve every vein, especially when major venous sinuses have been obliterated. Detailed study of high-quality preoperative digital subtraction angiography is extremely important. Venous injury should be repaired immediately whenever possible. Postrepair venous sinus thrombosis may be effectively salvaged by endovascular thrombectomy for rapid recannulation, with or without combined use of continuous in situ thrombolytic therapy.

Flow phantoms with anatomically realistic geometry and high acoustic compatibility are valuable investigative tools in vascular ultrasound studies. Here, we present a new framework to fabricate ultrasound-compatible flow phantoms to replicate human vasculature that is tortuous, nonplanar, and branching in nature. This framework is based upon the integration of rapid prototyping and investment casting principles. A pedagogical walkthrough of our engineering protocol is presented in this paper using a patient-specific cerebral aneurysm model as an exemplar demonstration. The procedure for constructing the flow circuit component of the phantoms is also presented, including the design of a programmable flow pump system, the fabrication of blood mimicking fluid, and flow rate calibration. Using polyvinyl alcohol cryogel as the tissue mimicking material, phantoms developed with the presented protocol exhibited physiologically relevant acoustic properties [attenuation coefficient: 0.229±0.032 dB/( $\text {cm}\cdot \text {MHz}$ ) and acoustic speed: 1535±2.4 m/s], and their pulsatile flow dynamics closely resembled the flow profile input. As a first application of our developed phantoms, the flow pattern of the patient-specific aneurysm model was visualized by performing high-frame-rate color-encoded speckle imaging over multiple time-synchronized scan planes. Persistent recirculation was observed, and the vortex center was found to shift in position over a cardiac cycle, indicating the 3-D nature of flow recirculation inside an aneurysm. These findings suggest that phantoms produced from our reported protocol can serve well as acoustically compatible test beds for vascular ultrasound studies, including 3-D flow imaging.