Mark Parsons

Infarct location has a critical effect on patient outcome after ischemic stroke, but the study of its role independent of overall lesion volume is challenging. We performed a retrospective, hypothesis-generating study of the effect of infarct location on three-month functional outcome in a pooled analysis of the EPITHET and DEFUSE studies. Posttreatment MRI diffusion lesions were manually segmented and transformed into standard-space. A novel composite brain atlas derived from three standard brain atlases and encompassing 132 cortical and sub-cortical structures was used to segment the transformed lesion into different brain regions, and calculate the percentage of each region infarcted. Classification and Regression Tree (CART) analysis was performed to determine the important regions in each hemisphere associated with nonfavorable outcome at day 90 (modified Rankin score [mRS] > 1). Overall, 152 patients (82 left hemisphere) were included. Median diffusion lesion volume was 37·...

NASA's Earth Science Enterprise has identified the need for improved measurement of snow properties and frozen soils via a space-flight mission within the next decade. Microwave sensors appear ideal to measure these properties. Measurements of the Earth's surface in the microwave spectral regions can be largely insensitive to weather conditions and solar illumination, which is especially important during cold seasons.

The Open Archival Information System (OAIS) Reference Model was developed by the Consultative Committee for Space Data Systems (CCSDS) in the late 1990s and was adopted as an ISO standard in 2003 (ISO14721: 2003)(CCSDS 650.0-B-1, 2002). Recently, many libraries, data centers, and archives around the world have started to adopt this archive model. As a notable example, the National Oceanographic and Atmospheric Administration (NOAA) of the United States of America adopted the model for their ...

To assess the differences across continental regions in terms of stroke imaging obtained for making acute revascularization therapy decisions, and to identify obstacles to participating in randomized trials involving multimodal imaging. STroke Imaging Repository (STIR) and Virtual International Stroke Trials Archive (VISTA)-Imaging circulated an online survey through its website, through the websites of national professional societies from multiple countries as well as through email distribution lists from STIR and the above mentioned societies. We received responses from 223 centers (2 from Africa, 38 from Asia, 10 from Australia, 101 from Europe, 4 from Middle East, 55 from North America, 13 from South America). In combination, the sites surveyed administered acute revascularization therapy to a total of 25 326 acute stroke patients in 2012. Seventy-three percent of these patients received intravenous (IV) tissue plasminogen activator (tPA), and 27%, endovascular therapy. Vascular...

The use of perfusion imaging to guide selection of patients for stroke thrombolysis remains controversial because of lack of supportive phase three clinical trial evidence. We aimed to measure the outcomes for patients treated with intravenous recombinant tissue plasminogen activator (rtPA) at a comprehensive stroke care facility where perfusion computed tomography was routinely used for thrombolysis eligibility decision assistance. Our overall hypothesis was that patients with 'target' mismatch on perfusion computed tomography would have improved outcomes with rtPA. This was a prospective cohort study of consecutive ischaemic stroke patients who fulfilled standard clinical/non-contrast computed tomography eligibility criteria for treatment with intravenous rtPA, but for whom perfusion computed tomography was used to guide the final treatment decision. The 'real-time' perfusion computed tomography assessments were qualitative; a large perfusion computed tomography ischaemic core, or lack of significant perfusion lesion-core mismatch were considered relative exclusion criteria for thrombolysis. Specific volumetric perfusion computed tomography criteria were not used for the treatment decision. The primary analysis compared 3-month modified Rankin Scale in treated versus untreated patients after 'off-line' (post-treatment) quantitative volumetric perfusion computed tomography eligibility assessment based on presence or absence of 'target' perfusion lesion-core mismatch (mismatch ratio >1.8 and volume…

Background and Purpose—Platelets and components of the coagulation cascade are known to be instrumental in the pathogenesis of arterial occlusive disorders. The aim of this meta-analysis is to test the hypothesis that genetic variation in the platelet glycoprotein 1b and Factor VII genes influence the occurrence of ischemic stroke. All genetic association studies that examined the R353Q (rs6046) polymorphism of

Background. Upper-limb (UL) dysfunction is experienced by up to 75% of patients poststroke. The greatest potential for functional improvement is in the first month. Following reperfusion, evidence indicates that neuroplasticity is the mechanism that supports this recovery. Objective. This preliminary study hypothesized increased activation of putative motor areas in those receiving intensive, task-specific UL training in the first month poststroke compared with those receiving standard care. Methods. This was a single-blinded, longitudinal, randomized controlled trial in adult patients with an acute, first-ever ischemic stroke; 23 participants were randomized to standard care (n = 12) or an additional 30 hours of task-specific UL training in the first month poststroke beginning week 1. Patients were assessed at 1 week, 1 month, and 3 months poststroke. The primary outcome was change in brain activation as measured by functional magnetic resonance imaging. Results. When compared with...

MRI is being increasingly used as a selection tool and an outcome measure in stroke trials, reflecting the growing evidence that direct pathophysiologic imaging may provide a more rational approach to acute stroke therapy than clinical diagnosis (and non-contrast CT scanning) alone. Stroke MRI is practical and feasible. Perfusion-diffusion mismatch provides a reliable estimation of the ischaemic penumbra. The future

The European Cooperative Acute Stroke Study (ECASS) III showed that intravenous recombinant tissue plasminogen activator (rtPA) administered in the 3 to 4.5 h after symptom onset significantly improved clinical outcomes in patients with acute ischemic stroke (AIS). But little is known regarding the safety and efficacy of intravenous rtPA treatment within this extended time window in Chinese patients with AIS. Data were collected from the Thrombolysis Implementation and Monitor of acute ischemic Stroke in China (TIMS-China). A total of 574 patients who underwent rtPA therapy within 4.5 h after symptom onset were included in this study: 409 in the 0- to 3-h group and 165 in the 3- to 4.5-h group. There were no significant differences in SICH rate (2.4% vs. 1.5%, P = 0.70) at 24 to 36 h, mortalities (7.5% vs. 7.3%, P = 0.84), independence rate (68.9% vs. 63.9%, P = 0.19), and excellent recovery rate (60.9% vs. 52.4%, P = 0.11) between the two time window groups. These results were comparable with previous Western studies. This study suggests that intravenous rtPA treatment at 3 to 4.5 h of symptom onset remains safe and effective in Chinese patients with AIS.

CLPX satellite measurements span the electromagnetic spectrum and include panchromatic, multispectral and hyperspectral observations in the spectral region of solar transmittance through the Earth Atmosphere, and both passive and active microwave observations at wavelengths ranging from millimeter to centimeter scales. Further, we expect opportunistic collections of multispectral measurements in the thermal infrared spectral region. The optical measurements span, in spatial

The Cold Land Processes Field Experiment (CLPX) is a multi-year effort to develop the quantitative understanding, models, and measurements necessary to extend our local-scale understanding of cold-region water fluxes, storage, and transformations to regional and global scales. Particularly emphasized is the development of a strong synergism between process-oriented understanding, land surface models and microwave remote sensing within a broad range

Diabetes mellitus is a complex metabolic syndrome with significant effects on the systemic and cerebral vasculature. The incidence and severity of ischaemic stroke are increased by the presence of diabetes, and outcome from stroke is poorer. More than one third of patients admitted with acute stroke are hyperglycaemic at presentation. Reasons for the altered prognosis in diabetes associated stroke are

Objective: To report initial experience with the use of intravenous tissue plasminogen activator (tPA) to treat acute ischaemic stroke at an Australian tertiary-care hospital. Design: Retrospective audit of computerised hospital stroke database. Participants and setting: All patients with acute ischaemic stroke treated with intravenous tPA between April 1999 and July 2002 at the Royal Melbourne Hospital, VIC. Main outcome measures:

The clinical-diffusion mismatch (CDM) model has been proposed as a simpler tool than perfusion-diffusion mismatch (PDM) to select acute ischemic stroke patients for thrombolytic therapy. We hypothesized that in the 3- to 6-hour time window, the effect of tPA was significantly greater in patients with CDM than in patients without CDM. This is a substudy of EPITHET, a double-blind multi-center study of 100 patients randomized to tPA or placebo 3 to 6 hours after stroke onset. MRI was obtained before treatment, and at 3 to 5 days and 90 days after treatment. Presence of PDM (perfusion deficit/DWI(volume) >1.2 and perfusion deficit at least 10 mL>DWI(volume)) and CDM (NIHSS >or=8 and DWI(volume) <or=25 mL) was determined for each patient. We assessed lesion growth and neurological improvement (decrease in NIHSS >or=8 points between baseline and 90 days, or a 90-day NIHSS…

ABSTRACT Snow, ice, and frozen ground impact a significant part of the earth's surface and natural cycles. Geographic information systems (GIS) are frequently used in studying and assessing the influence of environmental conditions on geophysical, ecological, or socioeconomic factors, but researchers, planners, and decision makers wishing to incorporate cryospheric information into GIS studies often must confront issues related to data formats, data accessibility, and data quality. The National Snow and Ice Data Center (NSIDC) is developing a repository of GIS resources that will simplify the process of identifying, obtaining, and incorporating appropriate cryospheric data into GIS studies. The initial thrust of this repository is base maps, georeferenced images, and other data layers that may be used to study interactions of cryospheric elements with the environment. Supportive narratives, in addition to existing metadata, will describe appropriate uses and explain competing products. Some products, such as the sea ice trends, are derived from satellite data, while others, such as the circumpolar soils map, are based on mapping of data from multiple ground-based and remote sensing sources. The repository will contain materials available from NSIDC as well as links to related products available from other sources. NSIDC considers feedback from existing and potential users regarding the goals, content, and structure of this repository an essential component of its development.

The aim of acute stroke treatment is to reperfuse the penumbra. However, not all posttreatment reperfusion is associated with a good outcome. Recent arterial spin labeling (ASL) studies suggest that patients with hyperperfusion after treatment have a better clinical recovery. This study aimed to determine whether there was a distinctive magnetic resonance spectroscopy (MRS) metabolite profile in hyperperfused tissue after stroke reperfusion therapy. We studied 77 ischemic stroke patients 24 hours after treatment using MRS (single voxel spectroscopy, point resolved spectroscopy, echo time 30 ms), ASL, and diffusion-weighted imaging (DWI). Magnetic resonance spectroscopy voxels were placed in cortical tissue that was penumbral on baseline perfusion imaging but had reperfused at 24 hours (and did not progress to infarction). Additionally, 20 healthy age matched controls underwent MRS. In all, 24 patients had hyperperfusion; 36 had reperfused penumbra without hyperperfusion, and 17 were...

A key element for the ultimate success of the International Polar Year (IPY) effort will be our ability to make the volumes of data collected in this work available and usable to researchers, both now and into the future. Ultimately, the IPY data will reside in a number of different repositories and will be accessed by users from a wide variety of disciplines and with a wide variety of needs. It is therefore important that appropriate informatics tools be developed and made available to the IPY community for indexing, searching, retrieving, and managing distributed polar data. Discovery, Access, and Delivery of Data for the IPY (DADDI) is a NASA-funded project involving multiple institutions, targeted at leveraging and evolving Earth Science informatics tools to meet the Informatics challenges of the IPY effort. To test our approaches, we have selected Arctic coastal data as a focus area for developing a working prototype of an IPY Informatics solution. Coastal areas are undergoing some of the most drastic changes within the polar regions and are also the area of most concentrated human activity at high latitudes. Coastal regions are also of interest to a broad range of disciplines and data customers, so this is an area where there is a high need for a robust Informatics infrastructure. In this presentation, I will review the requirements which we have collected for an information system to manage a dispersed collection of Arctic coastal data. I will then present the current version of the prototype which we are developing, discuss the ways in which the underlying tools can be leveraged out to other IPY- related areas, and discuss the lessons learned in developing this prototype information system.

Alteplase is effective for treatment of acute ischaemic stroke but debate continues about its use after longer times since stroke onset, in older patients, and among patients who have had the least or most severe strokes. We assessed the role of these factors in affecting good stroke outcome in patients given alteplase. We did a pre-specified meta-analysis of individual patient data from 6756 patients in nine randomised trials comparing alteplase with placebo or open control. We included all completed randomised phase 3 trials of intravenous alteplase for treatment of acute ischaemic stroke for which data were available. Retrospective checks confirmed that no eligible trials had been omitted. We defined a good stroke outcome as no significant disability at 3-6 months, defined by a modified Rankin Score of 0 or 1. Additional outcomes included symptomatic intracranial haemorrhage (defined by type 2 parenchymal haemorrhage within 7 days and, separately, by the SITS-MOST definition of p...

The legacy of the International Geophysical Year and past International Polar Years is in the scientific data collected. The upcoming IPY will result in an unprecedented collection of geophysical and social science data from the polar regions. To realize the full scientific and interdisciplinary utility of these data it is essential to consider the design of data management systems early in the expirimental planning process. This paper will present an array of high level data management considerations for the IPY including cross- ...

Background—The clinical diagnosis of subcortical cerebral infarction is inaccurate for lesion location and pathogenesis. Clinically suspected small perforating artery occlusions may be embolic infarcts, with important implications for investigation and treatment. New MRI techniques may allow more accurate determination of the stroke mechanism soon after admission. Methods—In a prospective series of 106 patients evaluated with acute diffusion-weighted MRI (DWI) and

Planning is currently underway for an International Polar Year (IPY) in 2007-2008. Like its predecessors, the IPYs of 1882-83 and 1932-33 and the International Geophysical Year in 1957-58 IPY's (and IGY's), the upcoming IPY will undoubtedly produce a wide variety of data and information useful not only to the current generation; but also for future generations. However, unlike previous IPY/IGYs, the bulk of that data and information is likely to be digital not analog. While preservation of anything for the long term is ...

Sea ice is a central element of the Arctic system and a strong indicator of high-latitude climate change. In addition to the many scientific disciplines in which sea ice is of importance, the domains of transportation, defense, natural resources and human settlements all have interests in and contribute to the body of knowledge regarding sea ice. To help advance the interdisciplinary understanding and usability of sea ice data we have developed a preliminary sea ice ontology. This effort began with a workshop in which sea ...

Background and Purpose—Apparent diffusion coefficient (ADC) thresholds for tissue infarction have been identified in acute stroke. IV tissue plasminogen activator (tPA) is associated with tissue salvage. We hypothesized that tPA would lower the ADC threshold for infarction. Methods—ADC and mean transit time (MTT) maps were generated for 26 patients imaged within 6 hours of stroke onset (12 tPA and 14