177 research outputs found

    Refractory High Intracranial Pressure following Intraventricular Hemorrhage due to Moyamoya Disease in a Pregnant Caucasian Woman

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    Intraventricular hemorrhage during pregnancy is usually followed by a poor recovery. When caused by moyamoya disease, ischemic or hemorrhagic episodes may complicate the management of high intracranial pressure. A 26-year-old Caucasian woman presented with generalized seizures and a Glasgow Coma Score (GCS) of 3 during the 36th week of pregnancy. The fetus was delivered by caesarean section. The brain CT in the mother revealed bilateral intraventricular hemorrhage, a callosal hematoma, hydrocephalus and right frontal ischemia. Refractory high intracranial pressure developed and required bilateral ventricular drainage and intensive care treatment with barbiturates and hypothermia. Magnetic resonance imaging and cerebral angiography revealed a moyamoya syndrome with rupture of the abnormal collateral vascular network as the cause of the hemorrhage. Intracranial pressure could only be controlled after the surgical removal of the clots after a large opening of the right ventricle. Despite an initially low GCS, this patient made a good functional recovery at one year follow-up. Management of refractory high intracranial pressure following moyamoya related intraventricular bleeding should require optimal removal of ventricular clots and appropriate control of cerebral hemodynamics to avoid ischemic or hemorrhagic complications

    Systematic InSAR tropospheric phase delay corrections from global meteorological reanalysis data

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    6p.International audienceDespite remarkable successes achieved by Differential InSAR, estimations of low tectonic strain rates remain challenging in areas where deformation and topography are correlated, mainly because of the topography‐related atmospheric phase screen (APS). In areas of high relief, empirical removal of the stratified component of the APS may lead to biased estimations of tectonic deformation rates. Here we describe a method to correct interferograms from the effects of the spatial and temporal variations in tropospheric stratification by computing tropospheric delay maps coincident with SAR acquisitions using the ERA‐ Interim global meteorological model. The modeled phase delay is integrated along vertical profiles at the ERA‐I grid nodes and interpolated at the spatial sampling of the interferograms above the elevation of each image pixel. This approach is validated on unwrapped interferograms. We show that the removal of the atmospheric signal before phase unwrapping reduces the risk of unwrapping errors in areas of rough topography

    Comparative overwiew of brain perfusion imaging techniques

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    Background and Purpose - Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are positron emission tomography, single photon emission computed tomography, Xenon-enhanced computed tomography, dynamic perfusion computed tomography, MRI dynamic susceptibility contrast, arterial spin labeling, and Doppler ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow or cerebral blood volume. All of them are used to characterize the same types of pathological conditions. However, each technique has its own advantages and drawbacks. Summary of Review - This article addresses the main imaging techniques dedicated to brain hemodynamics. It represents a comparative overview established by consensus among specialists of the various techniques. Conclusions - For clinicians, this article should offer a clearer picture of the pros and cons of currently available brain perfusion imaging techniques and assist them in choosing the proper method for every specific clinical setting

    Comparative overview of brain perfusion imaging techniques Epub

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    Background and Purpose - Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are positron emission tomography, single photon emission computed tomography, Xenon-enhanced computed tomography, dynamic perfusion computed tomography, MRI dynamic susceptibility contrast, arterial spin labeling, and Doppler ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow or cerebral blood volume. All of them are used to characterize the same types of pathological conditions. However, each technique has its own advantages and drawbacks. Summary of Review - This article addresses the main imaging techniques dedicated to brain hemodynamics. It represents a comparative overview established by consensus among specialists of the various techniques. Conclusions - For clinicians, this article should offer a clearer picture of the pros and cons of currently available brain perfusion imaging techniques and assist them in choosing the proper method for every specific clinical setting

    Magmatism on rift flanks: insights from ambient noise phase velocity in Afar region

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    During the breakup of continents in magmatic settings, the extension of the rift valley is commonly assumed to initially occur by border faulting and progressively migrate in space and time toward the spreading axis. Magmatic processes near the rift flanks are commonly ignored. We present phase velocity maps of the crust and uppermost mantle of the conjugate margins of the southern Red Sea (Afar and Yemen) using ambient noise tomography to constrain crustal modification during breakup. Our images show that the low seismic velocities characterize not only the upper crust beneath the axial volcanic systems but also both upper and lower crust beneath the rift flanks where ongoing volcanism and hydrothermal activity occur at the surface. Magmatic modification of the crust beneath rift flanks likely occurs for a protracted period of time during the breakup process and may persist through to early seafloor spreading

    Rapid response to the M_w 4.9 earthquake of November 11, 2019 in Le Teil, Lower RhĂŽne Valley, France

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    On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower RhĂŽne Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE-SW La Rouviere normal fault in reverse faulting in agreement with the present-day E-W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional CĂ©venne fault system in a context of present-day compressional tectonics

    Ground deformation monitoring of the eruption offshore Mayotte

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    In May 2018, the Mayotte island, located in the Indian Ocean, was affected by an unprecedented seismic crisis, followed by anomalous on-land surface displacements in July 2018. Cumulatively from July 1, 2018 to December 31, 2021, the horizontal displacements were approximately 21 to 25 cm eastward, and subsidence was approximately 10 to 19 cm. The study of data recorded by the on-land GNSS network, and their modeling coupled with data from ocean bottom pressure gauges, allowed us to propose a magmatic origin of the seismic crisis with the deflation of a deep source east of Mayotte, that was confirmed in May 2019 by the discovery of a submarine eruption, 50 km offshore of Mayotte ([Feuillet et al., 2021]). Despite a non-optimal network geometry and receivers located far from the source, the GNSS data allowed following the deep dynamics of magma transfer, via the volume flow monitoring, throughout the eruption

    COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

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    Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≀ 18 years: 69, 48, 23; 85%), older adults (≄ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
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