The Clinical and Radiological Outcomes of the Multimodal Use of the Woven EndoBridge Device: A Large Multicenter Study.

BACKGROUND: The Woven EndoBridge (WEB) is a device used for intrasaccular flow diversion, designed for the elimination of wide-necked bifurcation aneurysms from the circulation. In this study, we aim to assess the safety and efficacy of the WEB and its uses in treating aneurysms of different morphologies and locations. METHODS: In a retrospective analysis, we compiled a comprehensive dataset from patients treated with the WEB device across three major Australian neurovascular centers from May 2017 to September 2023. The case series encompassed a spectrum of aneurysm types, including wide-necked bifurcation, sidewall, and irregularly shaped aneurysms, as well as cases previously managed with alternative therapeutic strategies. This study additionally encompasses cases where aneurysms were managed using the WEB device in combination with supplementary endovascular devices. RESULTS: The study included 169 aneurysms in 161 patients. The rate of satisfactory aneurysm occlusion was 85.6%, with 86.7% of patients maintaining good functional status at their most recent follow-up. The procedure exhibited a low mortality rate of 0.6% and a thromboembolic complication rate of 7.1% (n = 12/161). There were no instances of postoperative re-rupture and the procedure-related hemorrhage rate was low (1.2%, n = 2/169), aligning with the literature regarding the safety and efficacy of the WEB device. CONCLUSIONS: Our multicenter trial reinforces the WEB device's role as an effective and safe modality for intracranial aneurysm management, supporting its expanded application beyond wide-necked bifurcation aneurysms. Further prospective studies are required to delineate its evolving role fully.

High-frequency optical coherence tomography for endovascular management of cerebral aneurysms.

Endovascular management of intracranial aneurysms has become the mainstay of treatment in recent years; however, retreatment rates remain as high as 1 in 5. High-frequency optical coherence tomography (HF-OCT) is an emerging imaging modality for the assessment, treatment and follow-up of cerebral aneurysms. EMBASE and SCOPUS databases were searched for studies relating to the management of intracranial aneurysm with OCT. A combination of keywords were used including 'cerebral aneurysm', 'intracranial aneurysm', 'high-frequency optical coherence tomography', 'optical coherence tomography', and 'optical frequency domain imaging'. There were 23 papers included in this review. For the assessment of intracranial aneurysm, OCT was able to accurately assess aneurysm morphology as well as detailed analysis of arterial wall layers. During IA treatment, OCT was used to assess and troubleshoot stent placement to optimise successful isolation from the circulation. In the follow-up period, endothelial growth patterns were visualised by OCT imaging. OCT shows promise for the treatment of IAs at all stages of management. Due to the novel development of HF-OCT, there is limited longitudinal data in human studies. Further research in this area is required with a focus specifically on long-term treatment outcomes in humans.

Occult contrast retention post-thrombectomy on 24-h follow-up dual-energy CT: Associations and impact on imaging analysis.

BACKGROUND: Following reperfusion treatment in ischemic stroke, computed tomography (CT) imaging at 24 h is widely used to assess radiological outcomes. Even without visible hyperattenuation, occult angiographic contrast may persist in the brain and confound Hounsfield unit-based imaging metrics, such as net water uptake (NWU). AIMS: We aimed to assess the presence and factors associated with retained contrast post-thrombectomy on 24-h imaging using dual-energy CT (DECT), and its impact on the accuracy of NWU as a measure of cerebral edema. METHODS: Consecutive patients with anterior circulation large vessel occlusion who had post-thrombectomy DECT performed 24-h post-treatment from two thrombectomy stroke centers were retrospectively studied. NWU was calculated by interside comparison of HUs of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention and bilateral infarcts were excluded. Cerebral edema was measured by relative hemispheric volume (rHV) and midline shift (MLS). RESULTS: Of 125 patients analyzed (median age 71 (IQR = 61-80), baseline National Institutes of Health Stroke Scale (NIHSS) 16 (IQR = 9.75-21)), reperfusion (defined as extended-Thrombolysis-In-Cerebral-Infarction 2b-3) was achieved in 113 patients (90.4%). Iodine-subtracted NWU was significantly higher than unadjusted NWU (17.1% vs 10.8%, p < 0.001). In multivariable median regression analysis, increased age (p = 0.024), number of passes (p = 0.006), final infarct volume (p = 0.023), and study site (p = 0.021) were independently associated with amount of retained contrast. Iodine-subtracted NWU correlated with rHV (rho = 0.154, p = 0.043) and MLS (rho = 0.165, p = 0.033) but unadjusted NWU did not (rHV rho = -0.035, p = 0.35; MLS rho = 0.035, p = 0.347). CONCLUSIONS: Angiographic iodine contrast is retained in brain parenchyma 24-h post-thrombectomy, even without visually obvious hyperdensities on CT, and significantly affects NWU measurements. Adjustment for retained iodine using DECT is required for accurate NWU measurements post-thrombectomy. Future quantitative studies analyzing CT after thrombectomy should consider occult contrast retention.

Computational Fluid Dynamics in Intracranial Atherosclerosis - Lessons from Cardiology: A Review of CFD in Intracranial Atherosclerosis.

BACKGROUND: Intracranial atherosclerosis is a common cause of stroke with a high recurrence rate. Haemodynamically significant lesions are associated with a particularly high risk of recurrence. Computational fluid dynamics (CFD) is a tool that has been investigated to identify haemodynamically significant lesions. CFD in the intracranial vasculature benefits from the precedent set by cardiology, where CFD is an established clinical tool. This precedent is particularly important in CFD as models are very heterogenous. There are many decisions-points in the model-creation process, usually involving a trade-off between computational expense and accuracy. OBJECTIVES: This study aimed to review published CFD models in intracranial atherosclerosis and compare them to those used in cardiology. METHODS: A systematic search for all published computational fluid dynamics models applied to intracranial atherosclerosis was performed. Each study was analysed as regards to the different steps in creating a fluid dynamics model and findings were compared with established cardiology CFD models. RESULTS AND CONCLUSION: 38 papers were screened and 12 were included in the final analysis. There were important differences between coronary and intracranial atherosclerosis models in the following areas: area of interest segmented, use of transient models vs steady-state models, boundary conditions, methods for solving the fluid dynamics equations and validation. These differences may be high-yield areas to explore for future research.

Advanced Imaging of Intracranial Atherosclerosis: Lessons from Interventional Cardiology.

Intracranial atherosclerosis is a major cause of ischemic stroke. Patients with a high degree of stenosis have a significant rate of stroke despite medical therapy. Two randomized trials of stenting have failed to show benefit. Improving periprocedural complication rates and patient selection may improve stenting outcomes. Fractional flow reserve (FFR), intravascular ultrasound (IVUS), and optical coherence tomography (OCT) are intravascular imaging techniques employed to improve patient selection and stent placement in interventional cardiology. FFR has been shown to improve cardiovascular outcomes when used in patient selection for intervention. Studies of FFR in intracranial atherosclerosis show that the measure may predict which plaques lead to stroke. IVUS is used in cardiology to quantify stenosis and assist with stent placement. Comparisons with histology show that it can reliably characterize plaques. Several case reports of IVUS in intracranial arteries show the technique to be feasible and indicate it may improve stent placement. Plaque characteristics on IVUS may help identify vulnerable plaques. In interventional cardiology, OCT provides excellent visualization of vessel geometry and is useful periprocedurally. Images reliably identify thin-capped fibroatheromas and other plaque features. Case reports indicate that OCT is safe for use in intracranial arteries. OCT can be used to identify perforator vessels and so may be useful in avoiding perforator strokes, a common complication of stenting. Plaque characteristics on OCT may be useful in patient selection.

Importance of spontaneous nystagmus detection in the differential diagnosis of acute vertigo.

Vertigo is a common cause of emergency department attendance. Detection of spontaneous nystagmus may be a useful sign in distinguishing vestibular neuritis from other vestibular diagnoses. We aimed to assess the contribution of spontaneous nystagmus in the diagnosis of acute vertigo. We enrolled consecutive consenting patients arriving at a single emergency department with acute vertigo. There was no declared protocol for the emergency department staff. A standardized history and examination was conducted by the investigators. Observation for spontaneous nystagmus, its response to visual fixation, and testing the vestibulo-ocular reflex with the horizontal head impulse test were the chief examination components. MRI was obtained within 24 hours. Clinical criteria and MRI were used to reach the final diagnosis. The investigators' physical findings and final neurological diagnosis were compared with the initial emergency department examination findings and the referral diagnosis. There were 28 patients, 15 with vestibular neuritis, six with benign paroxysmal positional vertigo, one with stroke, suspected clinically, and three with migraine. In three the diagnosis remained uncertain. Spontaneous nystagmus was seen in all 15 patients with vestibular neuritis, fixation-suppressed in eight of 11 tested for this. The head impulse test was positive in 12 of 15 with vestibular neuritis. The emergency department referral diagnosis was correct in six of 23 patients. The ability to detect spontaneous nystagmus is useful in vestibular diagnosis, both in support of a diagnosis of vestibular neuritis and in avoiding false positive diagnoses of benign paroxysmal positional vertigo.