Establishment of viral persistence in cell culture has previously led to the selection of mammalian reovirus mutants, although very few of those have been characterized in details. In the present study, reovirus was adapted to Vero cells that, in contrast to classically-used L929 cells, are inefficient in supporting the early steps of reovirus uncoating and are also unable to produce interferon as an antiviral response once infection occurs. The Vero cell-adapted reovirus exhibits amino acids substitutions in both the σ1 and μ1 proteins. This contrasts with uncoating mutants from persistently infected L929 cells, and various other cell types, that generally harbor amino acids substitutions in the σ3 outer capsid protein. The Vero cell-adapted virus remained sensitive to an inhibitor of lysosomal proteases; furthermore, in the absence of selective pressure for its maintenance, the virus has partially lost its ability to resist interferon. The positions of the amino acids substitutions on the known protein structures suggest an effect on binding of the viral σ1 protein to the cell surface and on μ1 disassembly from the outer capsid.

BACKGROUND AND PURPOSE: Computed tomography angiography offers a non-invasive alternative to DSA for the assessment of cerebral vasospasm following subarachnoid hemorrhage but there is limited evidence regarding its reliability. Our aim was to perform a systematic review (Part I) and to assess (Part II) the inter-and intraobserver reliability of CTA in the diagnosis of cerebral vasospasm. MATERIALS AND METHODS:In Part I, articles reporting the reliability of CTA up to May 2018 were systematically searched and evaluated. In Part II, 11 raters independently graded 17 arterial segments in each of 50 patients with SAH for the presence of vasospasm using a 4-category scale. Raters were additionally asked to judge the presence of any moderate/severe vasospasm ($ 50% narrowing) and whether findings would justify augmentation of medical treatment or conventional angiography 6 balloon angioplasty. Four raters took part in the intraobserver reliability study. RESULTS:In Part I, the systematic review revealed few studies with heterogeneous vasospasm definitions. In Part II, we found interrater reliability to be moderate at best (k # 0.6), even when results were stratified according to specialty and experience. Intrarater reliability was substantial (k . 0.6) in 3/4 readers. In the per arterial segment analysis, substantial agreement was reached only for the middle cerebral arteries, and only when senior raters' judgments were dichotomized (presence or absence of $50% narrowing). Agreement on the medical or angiographic management of vasospasm based on CTA alone was less than substantial (k # 0.6). CONCLUSIONS:The diagnosis of vasospasm using CTA alone was not sufficiently repeatable among observers to support its general use to guide decisions in the clinical management of patients with SAH.

BACKGROUND Vascular encasement by skull base chordomas can increase surgical risk and hinder completeness of resection. However, the evidence behind this remains anecdotic. OBJECTIVE To give a better portrayal of chordomas encasing vertebrobasilar arteries mainly in regard of surgical vascular risk and its impact on extent of resection. METHODS A retrospective cohort study comparing skull base chordomas with encasement (≥180o encirclement) of the vertebrobasilar arteries to a control group of skull base chordomas with intradural extension. Data gathered involved pre- and postoperative volumetric analysis of the tumor, degree of encasement of involved vessel, occurrence of complication, and survival data including progression-free survival (PFS) and overall survival (OS). RESULTS A total of 24 patients with vertebrobasilar encasement were included in the study and an equal number of control cases were randomly selected from the same time period, totalizing 48 patients. Lower clival tumors with condyle involvement were more likely to have encasement. Gross total resection (GTR) rate was significantly lower in the encasement group (13% vs 42%, P = .023). Rates of postoperative new neurological deficit, CFS leak and 30 d postoperative mortality were not statistically different between groups. There was no statistically significant difference in mean PFS (P = .608) and OS (P = .958). CONCLUSION Skull base chordomas encasing vertebrobasilar arteries are highly challenging tumors. This study demonstrates that although safe resection is possible, GTR is hindered by the presence of encasement. We advocate letting the tumor's adherence to vessels lead the resection, leaving a small piece of tumor behind if adherent to the vessels.

BACKGROUND:Middle meningeal artery (MMA) embolization has recently emerged as a treatment option for chronic subdural hematoma (cSDH). It is considered a simple and potentially safe endovascular procedure.OBJECTIVE:To compare between 2 different embolic agents; onyx (ethylene vinyl alcohol) and emboparticles (polyvinyl alcohol particles—PVA) for endovascular treatment of cSDH.METHODS:A retrospective analysis of all patients who underwent MMA embolization for cSDH treatment in 2 comprehensive centers between August 2018 and December 2021. Primary outcomes were failure of embolization and need for rescue surgical evacuation.RESULTS:Among 97 MMA embolizations, 49 (50.5%) received onyx and 48 (49.5%) received PVA. The presence of acute or subacute on cSDH was higher in the PVA group 11/49 (22.5%) vs 30/48 (62.5%), respectively, P < .001. There were no significant differences between both groups regarding failure of embolization 6/49 (12.2%) vs 12/48 (25.0%), respectively, P = .112, and need of unplanned rescue surgical evacuation 5/49 (10.2%) vs 8/48 (16.7%), respectively, P = .354. Hematoma thickness at late follow-up was significantly smaller in the PVA group 7.8 mm vs 4.6 mm, respectively; P = .017.CONCLUSION:Both onyx and PVA as embolic agents for cSDH can be used safely and have comparable clinical and surgical outcomes.

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Mechanical thrombectomy (MT) for ischemic stroke due to large vessel occlusion is standard of care. Evidence-based guidelines on eligibility for MT have been outlined and evidence to extend the treatment benefit to more patients, particularly those at the extreme ends of a stroke clinical severity spectrum, is currently awaited. As patient selection continues to be explored, there is growing focus on procedure selection including the tools and techniques of thrombectomy and associated outcomes. Artificial intelligence (AI) has been instrumental in the area of patient selection for MT with a role in diagnosis and delivery of acute stroke care. Machine learning algorithms have been developed to detect cerebral ischemia and early infarct core, presence of large vessel occlusion, and perfusion deficit in acute ischemic stroke. Several available deep learning AI applications provide ready visualization and interpretation of cervical and cerebral arteries. Further enhancement of AI techniques to potentially include automated vessel probe tools in suspected large vessel occlusions is proposed. Value of AI may be extended to assist in procedure selection including both the tools and technique of thrombectomy. Delivering personalized medicine is the wave of the future and tailoring the MT treatment to a stroke patient is in line with this trend. K E Y W O R D Sartificial intelligence, mechanical thrombectomy, stroke significantly improved patient selection and delivery of acute stroke care. 12,13 In recent years, there has been a marked improvement in thrombectomy device technology and refinements in procedure techniques. In times of growing scientific interest and shifting focus on 798

Mechanical thrombectomy is established as standard of care in the management of acute ischemic stroke due to large vessel occlusion and evidence-based guidelines for mechanical thrombectomy have been defined. As research continues to further expand the eligibility criteria for thrombectomy and the number of thrombectomy procedures increase worldwide, there is also growing focus on innovation of thrombectomy devices, procedural techniques, and related outcomes. Thrombectomy primarily involves use of stent retrievers and distal aspiration techniques, but variations and different combinations of techniques have been reported. As this is a rapidly evolving area in stroke management, there is debate as to which, if any, of these techniques leads to improved clinical outcomes over another and there is a lack of data comparing them. In this review, currently published and distinct techniques of mechanical thrombectomy are described methodically along with illustrations to aid in understanding the subtle differences between the techniques. The perceived benefits of each variation are discussed.

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