74 research outputs found

    Determinants of Deep Gray Matter Atrophy in Multiple Sclerosis: A Multimodal MRI Study

    Get PDF
    Deep gray matter involvement is a consistent feature in multiple sclerosis. The aim of this study was to evaluate the relationship between different deep gray matter alterations and the development of subcortical atrophy, as well as to investigate the possible different substrates of volume loss between phenotypes. Seventy-seven patients with MS (52 with relapsing-remitting and 25 with progressive MS) and 41 healthy controls were enrolled in this cross-sectional study. MR imaging investigation included volumetric, DTI, PWI and Quantitative Susceptibility Mapping analyses. Deep gray matter structures were automatically segmented to obtain volumes and mean values for each MR imaging metric in the thalamus, caudate, putamen, and globus pallidus. Between-group differences were probed by ANCOVA analyses, while the contribution of different MR imaging metrics to deep gray matter atrophy was investigated via hierarchic multiple linear regression models. Patients with MS showed a multifaceted involvement of the thalamus and basal ganglia, with significant atrophy of all deep gray matter structures (P.001). In the relapsing-remitting MS group,WMlesion burden proved to be the main contributor to volume loss for all deep gray matter structures (P .006), with a minor role of local microstructural damage, which, in turn, was the main determinant of deep gray matter atrophy in patients with progressive MS (P .01), coupled with thalamic susceptibility changes (P .05). Our study confirms the diffuse involvement of deep gray matter in MS, demonstrating a different behavior between MS phenotypes, with subcortical GM atrophy mainly determined by global WM lesion burden in patients with relapsing-remitting MS, while local microstructural damage and susceptibility changes mainly accounted for the development of deep gray matter volume loss in patients with progressive MS

    HARMONI at ELT: overview of the capabilities and expected performance of the ELT's first light, adaptive optics assisted integral field spectrograph.

    Get PDF

    X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope

    Get PDF
    X-shooter is the first 2nd generation instrument of the ESO Very Large Telescope(VLT). It is a very efficient, single-target, intermediate-resolution spectrograph that was installed at the Cassegrain focus of UT2 in 2009. The instrument covers, in a single exposure, the spectral range from 300 to 2500 nm. It is designed to maximize the sensitivity in this spectral range through dichroic splitting in three arms with optimized optics, coatings, dispersive elements and detectors. It operates at intermediate spectral resolution (R~4,000 - 17,000, depending on wavelength and slit width) with fixed echelle spectral format (prism cross-dispersers) in the three arms. It includes a 1.8"x4" Integral Field Unit as an alternative to the 11" long slits. A dedicated data reduction package delivers fully calibrated two-dimensional and extracted spectra over the full wavelength range. We describe the main characteristics of the instrument and present its performance as measured during commissioning, science verification and the first months of science operations.Comment: accepted for publication in A&

    The E-ELT first light spectrograph HARMONI: capabilities and modes

    Get PDF
    Trabajo presentado en SPIE Astronomical Telescopes, celebrado en San Diego (California), del 26 de junio al 1 de julio de 2016HARMONI is the E-ELT's first light visible and near-infrared integral field spectrograph. It will provide four different spatial scales, ranging from coarse spaxels of 60 × 30 mas best suited for seeing limited observations, to 4 mas spaxels that Nyquist sample the diffraction limited point spread function of the E-ELT at near-infrared wavelengths. Each spaxel scale may be combined with eleven spectral settings, that provide a range of spectral resolving powers (R 3500, 7500 and 20000) and instantaneous wavelength coverage spanning the 0.5 - 2.4 ¿m wavelength range of the instrument. In autumn 2015, the HARMONI project started the Preliminary Design Phase, following signature of the contract to design, build, test and commission the instrument, signed between the European Southern Observatory and the UK Science and Technology Facilities Council. Crucially, the contract also includes the preliminary design of the HARMONI Laser Tomographic Adaptive Optics system. The instrument's technical specifications were finalized in the period leading up to contract signature. In this paper, we report on the first activity carried out during preliminary design, defining the baseline architecture for the system, and the trade-off studies leading up to the choice of baseline

    Preliminary Evaluation of Percutaneous Treatment of Echinococcal Cysts without Injection of Scolicidal Agent.

    No full text
    Puncture, Aspiration, Injection of scolicidal agent, Re-aspiration is the most widely used percutaneous treatment of cystic echinococcosis (CE). Among its perceived risks is chemical sclerosing cholangitis, a serious complication due to the caustic effect of the scolicidal solution on the biliary tree, when a patent cystobiliary fistula occurs. To simplify the protocol, we decided to omit injection and reaspiration of the scolicidal agent and to implement a full course of albendazole (ABZ) therapy instead of the routine 1-month ABZ prophylaxis. We searched our databases for patients with CL (Cystic Lesion, suspected for CE), CE1, and CE3a cysts treated between October 2007 and January 2017 with percutaneous aspiration followed by at least 1 month of oral ABZ and with an ultrasound follow-up of at least 6 months. Fifteen patients matched our inclusion criteria. Follow-up ranged from 7 to 75 months. The oral ABZ course after the aspiration procedure ranged from 1 to 18 months. Eleven subjects (73.3%) had undergone a course of ABZ before the percutaneous procedure (min 15 days, max 16 months). Ten cysts (62.5%) had reached solidification (stage CE4) in 3 to 69 months. Four other cysts (26.7%) remained stable in stage CE3a, whereas two cysts (13.3%) reactivated to stage CE3b. Procedural perioperative complications occurred in 13.3% of patients, whereas complications during the follow-up occurred in 20% of patients. These proof-of-concept preliminary results are overall comparable with those reported in the literature for other percutaneous treatments, both in terms of response rate, relapse rate, and morbidity

    Cardiac risk assessment of asymptomatic patients by stress echocardiography before infrarenal aortic aneurysm surgery

    No full text
    AIM: Aggressive cardiac assessment before aortic abdominal aneurysm (AAA) surgery is indicated for patients with symptomatic coronary artery disease (CAD). Assessment of intermediate and moderate risk patients is still under debate. The purpose of the study was to prospectively evaluate the effectiveness of stress echocardiography (SE) in the detection of CAD in patients undergoing AAA surgery who have no symptoms and/or signs of CAD, but who have risk factors for it. METHODS: Patients with 1 or more risk factors for CAD underwent SE. All patients with positive SE underwent coronary arteriography, and, when indicated, treatment. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for SE by comparing results to coronary arteriography. Moreover, major perioperative cardiac events were recorded. RESULTS: Ninety-one patients with AAA and risk factors for CAD were studied. SE was positive in 9 cases, including 7 presenting critical CAD on the basis of coronary arteriography. One major cardiac event (1.1%), a nonfatal myocardial infarction, occurred in 1 patient with positive SE and non-critical, single-vessel CAD. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SE proved to be 100%, 98%, 78%, 100%, and 92%, respectively. CONCLUSIONS: Positive SE should be considered a valid method for testing high-risk patients for CAD. The low rate of major cardiac events in this series suggests that cardiac assessment by SE and selective coronary arteriography prior to AAA surgery is effective in asymptomatic patients with one or more risk factors
    • 

    corecore