427 research outputs found

    A CPH-Like Picture in Two Patients with an Orbitocavernous Sinus Syndrome

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    Two patients with retroorbital pain syndromes with or without paresis of cranial nerves developed weeks after ipsilateral headache resembling chronic paroxysmal hemicrania (CPH) but without autonomic features. These findings might support the hypothesis that CPH may be caused by a pathological process in the region of the cavernous sinus, as has been proposed for the Tolosa-Hunt syndrome (THS)

    Attitudes about Medical Malpractice: An American Society of Neuroradiology Survey

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    ABSTRACT SUMMARY: The concern over medicolegal liability is pervasive among physicians. We sought, through an email survey to the members of the ASNR, to assess the experience with and attitudes about the medicolegal environment among neuroradiologists. Of 4357 physicians surveyed, 904 answered at least 1 of the questions in the survey; 449 of 904 (49.7%) had been sued: 180 (44.9%) had been sued once, 114 (28.4%) twice, 60 (15.0%) 3 times, and 47 (11.7%) more than 3 times. The payouts for suits were most commonly in the 50,000to50,000 to 150,000 range, except for interventional neuroradiologists, in whom the most common value was 600,000to600,000 to 1,200,000. Only 9 of 481 (1.9%) of suits returned a plaintiff verdict. Despite reported outcomes that favored physicians with respect to cases being dropped (270/481 ϭ 56.1%), settled without a payment (11/481 ϭ 2.3%), or a defense verdict (46/481 ϭ 9.6), most respondents (81.1%, 647/798) believed that the medicolegal system was weighted toward plaintiffs. More than half of the neuroradiologists (55.2%, 435/787) reported being mildly to moderately concerned, and 19.1% (150/787) were very or extremely concerned about being sued. ABBREVIATIONS: ASN

    IS MRI-BASED VOLUME A MEDIATOR OF THE ASSOCIATION OF CUMULATIVE LEAD DOSE WITH COGNITIVE FUNCTION?

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    This work considers the pathway through which past occupational lead exposure impacts cognitive function using cross-sectional data. It is motivated by studies linking cumulative lead dose with brain volumes, volumes with cognitive function, and lead dose with cognitive function. It is hypothesized that the brain regions associated with lead mediate a portion of the association between lead dose and cognitive function. The data were derived from an ongoing study of 513 former organolead manufacturing workers. Using MRIs, a novel analysis was performed to investigate Mediation. Volumes associated with cognitive function and lead dose were derived using registered images and used in a subsequent mediation analysis. Cumulative lead dose was associated with adverse function in the visuo-construction, executive functioning and eye-hand coordination domains. Of these, there was strong evidence of volumetric mediation of lead’s effect on cognition in the visuo-construction domain, a moderate amount for eye-hand coordination, and limited evidence for executive functioning. A second path analysis based approach was also performed. To address the possibility that chance associations explained these findings, a permuted analysis was conducted, the results of which support the mediation inferences. The approach to the evaluation of volumetric mediation may have general applicability in epidemiologic neuroimaging settings

    FUNCTIONAL PRINCIPAL COMPONENTS MODEL FOR HIGH-DIMENSIONAL BRAIN IMAGING

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    We establish a fundamental equivalence between singular value decomposition (SVD) and functional principal components analysis (FPCA) models. The constructive relationship allows to deploy the numerical efficiency of SVD to fully estimate the components of FPCA, even for extremely high-dimensional functional objects, such as brain images. As an example, a functional mixed effect model is fitted to high-resolution morphometric (RAVENS) images. The main directions of morphometric variation in brain volumes are identified and discussed

    Policies and reporting guidelines for small biopsy specimens of mediastinal masses

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    目前,胸腺恶性肿瘤治疗方案大多是根据术\ud 后病理确定,然而,多数临床治疗决策需要在术前\ud 通过活检小标本的病理报告来制定。所以,术前活\ud 检小标本的正确获取和病理解读对治疗决策的制定\ud 显得非常重要[1]。这些标本包括细针活检标本,带\ud 芯穿刺活检标本和手术切取活检标本[2-7]。由于胸\ud 腺肿瘤的病理诊断对组织的获取方法和获取量都有较高\ud 的要求,加之对病理的描述也没有统一的标准,使得小\ud 标本在诊断胸腺瘤方面存在诸多问题。为此,ITMIG在\ud 病理科医生和外科医生回顾相关文献和提出初步建议的\ud 基础上,经集体讨论制定了活检规范操作流程,提出了\ud 对纵隔肿物小活检标本处理和病理报告的建议。旨在为\ud 术前患者的治疗提供一个统一和具有循证医学证据的方\ud 法;同时,将有利于全球数据之间的比较和开展合作研\ud 究,充分利用医疗资源

    MULTILEVEL FUNCTIONAL PRINCIPAL COMPONENT ANALYSIS FOR HIGH-DIMENSIONAL DATA

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    We propose fast and scalable statistical methods for the analysis of hundreds or thousands of high dimensional vectors observed at multiple visits. The proposed inferential methods avoid the difficult task of loading the entire data set at once in the computer memory and use sequential access to data. This allows deployment of our methodology on low-resource computers where computations can be done in minutes on extremely large data sets. Our methods are motivated by and applied to a study where hundreds of subjects were scanned using Magnetic Resonance Imaging (MRI) at two visits roughly five years apart. The original data possesses over ten billion easurements. The approach can be applied to any type of study where data can be unfolded into a long vector including densely bserved functions and images

    Genetic Risk Factors for Longitudinal Changes in Structural MRI in Former Organolead Workers

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    This study examined associations between polymorphisms in three genes, apolipoprotein E (APOE), angiotensin converting enzyme (ACE), and vitamin D receptor (VDR), and longitudinal change in brain volumes and white matter lesions (WML) as well as effect modification by cardiovascular factors and tibia lead concentrations. Two MRIs, an average of 5 years apart, were obtained for 317 former organolead workers and 45 population-based controls. Both regions-of-interest and voxel-wise analyses were conducted. APOE ε3/ε4 and ε4/ε4 genotypes were associated with less decline in white matter volumes. There was some evidence of interaction between genetic polymorphisms and cardiovascular risk factors (ACE and high-density lipoprotein; VDR and diabetes) on brain volume decline. The VDR FokI ff genotype was associated with an increase in WML (no association for APOE or ACE). This study expands our understanding of how genetic precursors of dementia and cardiovascular diseases are related to changes in brain structure

    ON THE MERITS OF VOXEL-BASED MORPHOMETRIC PATH-ANALYSIS FOR INVESTIGATING VOLUMETRIC MEDIATION OF A TOXICANT\u27S INFLUENCE ON COGNITIVE FUNCTION

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    We previously showed that lifetime cumulative lead dose, measured as lead concentration in the tibia bone by X-ray fluorescence, was associated with persistent and progressive declines in cognitive function and with decreases in MRI-based brain volumes in former lead workers. Moreover, larger region-specific brain volumes were associated with better cognitive function. These findings motivated us to explore a novel application of path analysis to evaluate effect mediation. Voxel-wise path analysis, at face value, represents the natural evolution of voxel-based morphometry methods to answer questions of mediation. Application of these methods to the former lead worker data demonstrated potential limitations in this approach where there was a tendency for results to be strongly biased towards the null hypothesis (lack of mediation). Moreover, a complimentary analysis using anatomically-derived regions of interest volumes yielded opposing results, suggesting evidence of mediation. Specifically, in the ROI-based approach, there was evidence that the association of tibia lead with function in three cognitive domains was mediated through the volumes of total brain, frontal gray matter, and/or possibly cingulate. A simulation study was conducted to investigate whether the voxel-wise results arose from an absence of localized mediation, or more subtle defects in the methodology. The simulation results showed the same null bias evidenced as seen in the lead workers data. Both the lead worker data results and the simulation study suggest that a null-bias in voxel-wise path analysis limits its inferential utility for producing confirmatory results

    Effects of donor bone marrow infusion in clinical lung transplantation

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    Background. We have demonstrated that donor cell chimerism is associated with a lower incidence of obliterative bronchiolitis (OB) in lung recipients, and that donor chimerism is augmented by the infusion of donor bone marrow (BM). We herein report the intermediate results of a trial combining the infusion of donor BM and lung transplantation. Methods. Clinical and in vitro data of 26 lung recipients receiving concurrent infusion of donor bone marrow (3.0 to 6.0 x 108 cells/kg) were compared with those of 13 patients receiving lung transplant alone. Results. Patient survival and freedom from acute rejection were similar between groups. Of the patients whose graft survived greater than 4 months, 5% (1 of 22) of BM and 33% (4 of 12) of control patients, developed histologic evidence of OB (p = 0.04). A higher proportion (but not statistically significant) of BM recipients (7 of 10, 70%) exhibited donor-specific hyporeactivity by mixed lymphocyte reaction assays as compared with the controls (2 of 7, 28%). Conclusions. Infusion of donor BM at the time of lung transplantation is safe, and is associated with recipients' immune modulation and a lower rate of obliterative bronchiolitis. (C) 2000 by The Society of Thoracic Surgeons
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