83 research outputs found

    PICA communicating artery aneurysm

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    This report presents a rare case of such an aneurysm arising from such a communicating artery. A 66-year-old woman presented with a subarachnoid hemorrhage located predominantly in the cisterna magna with intraventricular hemorrhage. Angiography showed hypoplasia of the right posterior inferior cerebellar artery. Its vermian territory was supplied by the communicating artery from the posterior medullary segments of the left posterior inferior cerebellar artery. An aneurysm was on that communicating artery itself at a nonbranching site. The aneurysm was trapped the next day. Postoperative computed tomography showed no infarct in the right posterior inferior cerebellar artery territory. Trapping is applicable when other collateral vessels supply the contralateral posterior inferior cerebellar artery territory

    Significance of High-frequency Electrical Brain Activity

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     Electroencephalogram (EEG) data include broadband electrical brain activity ranging from infra-slow bands (200 / 250 Hz, respectively) are particularly of note due to their very close relationship to epileptogenicity, with the possibility that they could function as a surrogate biomarker of epileptogenicity. In contrast, physiological high-frequency activity plays an important role in higher brain functions, and the differentiation between pathological / epileptic and physiological HFOs is a critical issue, especially in epilepsy surgery. HFOs were initially recorded with intracranial electrodes in patients with intractable epilepsy as part of a long-term invasive seizure monitoring study. However, fast oscillations (FOs) in the ripple and gamma bands (40-80 Hz) are now noninvasively detected by scalp EEG and magnetoencephalography, and thus the scope of studies on HFOs /FOs is rapidly expanding

    Correlations Among Consistency, Computed Tomography Values, and Histopathological Subtypes of Spinal Meningioma

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    The consistency of spinal meningiomas is important to consider when performing tumor removal surgery. This study evaluated the correlations between spinal meningioma consistency and both preoperative computed tomography (CT) values and histopathological subtypes. Fifteen consecutive patients who underwent surgical resection of spinal meningioma at our institution were identified, and preoperative CT values and the signal intensity of T2-weighted magnetic resonance images of the tumor were determined retrospectively. The consistency of the spinal meningioma was defined based on the ultrasonic surgical aspirator output during tumor debulking. Patients were assigned to 2 groups: a soft group (n=4) and a hard group (n=11). The T2 signal intensity was significantly higher in the soft group than in the hard group (p=0.001). While the CT values were considerably higher in the hard group, the difference was not significant (p=0.19). Regarding the histopathological subtypes, psammomatous meningioma exhibited significantly higher CT values than meningothelial meningioma (p=0.019); however, there was a higher frequency of hard tumors in meningothelial meningioma cases than in psammomatous meningioma cases. Although neither robust correlations between tumor consistency and CT values nor a relationship between tumor consistency and histopathological subtype has been established, these results might help with the perioperative manegement of spinal tumors

    The role of methane in future climate strategies: mitigation potentials and climate impacts

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    This study examines model-specific assumptions and projections of methane (CH4) emissions in deep mitigation scenarios generated by integrated assessment models (IAMs). For this, scenarios of nine models are compared in terms of sectoral and regional CH4 emission reduction strategies, as well as resulting climate impacts. The models’ projected reduction potentials are compared to sector and technology-specific reduction potentials found in literature. Significant cost-effective and non-climate policy related reductions are projected in the reference case (10–36% compared to a “frozen emission factor” scenario in 2100). Still, compared to 2010, CH4 emissions are expected to rise steadily by 9–72% (up to 412 to 654 Mt CH4/year). Ambitious CO2 reduction measures could by themselves lead to a reduction of CH4 emissions due to a reduction of fossil fuels (22–48% compared to the reference case in 2100). However, direct CH4 mitigation is crucial and more effective in bringing down CH4 (50–74% compared to the reference case). Given the limited reduction potential, agriculture CH4 emissions are projected to constitute an increasingly larger share of total anthropogenic CH4 emissions in mitigation scenarios. Enteric fermentation in ruminants is in that respect by far the largest mitigation bottleneck later in the century with a projected 40–78% of total remaining CH4 emissions in 2100 in a strong (2 °C) climate policy case
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