PVEs

  • 文章类型: Journal Article
    目的:使用神经盲解卷积同时对前列腺特异性膜抗原(PSMA)正电子发射断层扫描(PET)图像进行模糊和超采样。方法:盲解卷积是一种同时估计假设的“去模糊”图像以及模糊核(与点扩散函数相关)的方法。传统的最大后验盲反褶积方法需要严格的假设,并且会收敛到琐碎的解决方案。一种用独立神经网络对去模糊图像和核建模的方法,被称为“神经盲去卷积”的人在2020年证明了对2D自然图像进行去模糊的成功。在这项工作中,我们采用神经盲反卷积对PSMAPET图像进行PVE校正,同时进行超采样。我们将这种方法与几种插值方法进行比较,使用盲图像质量度量,并通过在将人工“伪内核”应用于去模糊图像后重新运行模型来测试模型预测内核的能力。该方法在30名前列腺患者的回顾性集合以及包含各种体积的球形病变的体模图像上进行了测试。主要结果:神经盲反卷积在盲图像质量度量方面比其他插值方法提高了图像质量,恢复系数,视觉评估。患者之间预测的内核相似,该模型准确地预测了几个人工应用的伪核。去模糊后,幻像球中活动的定位得到了改善,允许更准确地定义小病变。意义:PSMAPET的固有低空间分辨率导致PVE,其负面影响小区域中的摄取定量。所提出的方法可以用来缓解这个问题,并且可以直接适用于其他成像模式。
    Objective. To simultaneously deblur and supersample prostate specific membrane antigen (PSMA) positron emission tomography (PET) images using neural blind deconvolution.Approach. Blind deconvolution is a method of estimating the hypothetical \'deblurred\' image along with the blur kernel (related to the point spread function) simultaneously. Traditionalmaximum a posterioriblind deconvolution methods require stringent assumptions and suffer from convergence to a trivial solution. A method of modelling the deblurred image and kernel with independent neural networks, called \'neural blind deconvolution\' had demonstrated success for deblurring 2D natural images in 2020. In this work, we adapt neural blind deconvolution to deblur PSMA PET images while simultaneous supersampling to double the original resolution. We compare this methodology with several interpolation methods in terms of resultant blind image quality metrics and test the model\'s ability to predict accurate kernels by re-running the model after applying artificial \'pseudokernels\' to deblurred images. The methodology was tested on a retrospective set of 30 prostate patients as well as phantom images containing spherical lesions of various volumes.Main results. Neural blind deconvolution led to improvements in image quality over other interpolation methods in terms of blind image quality metrics, recovery coefficients, and visual assessment. Predicted kernels were similar between patients, and the model accurately predicted several artificially-applied pseudokernels. Localization of activity in phantom spheres was improved after deblurring, allowing small lesions to be more accurately defined.Significance. The intrinsically low spatial resolution of PSMA PET leads to partial volume effects (PVEs) which negatively impact uptake quantification in small regions. The proposed method can be used to mitigate this issue, and can be straightforwardly adapted for other imaging modalities.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    聚乙烯基醚硅氧烷(PVES)具有用于制作精确和准确的牙科印模的理想特性。PVES的尺寸稳定性归因于其母体材料聚醚和聚乙烯基硅氧烷的更好的聚合物性能。随着化学消毒剂的推荐使用越来越受欢迎,人们越来越关注消毒剂对PVES尺寸稳定性的影响。本研究旨在了解PVES在化学消毒剂作用下的行为。
    这些数据是从GoogleScholar检索的研究中收集的,Scopus,和PubMed使用关键字“乙烯基聚醚硅氧烷和消毒”或(乙烯基聚醚硅氧烷或聚乙烯硅氧烷醚或PVES)和(消毒剂或消毒)“的MeSH术语,对出版日期没有任何限制。在数据收集期间观察到PRISMA(系统评价和荟萃分析的首选报告项目)方向,筛选研究,和荟萃分析。检索了主要数据,并使用Harzing的Publish或Perish软件从数据库中批量导出;主要分析在MicrosoftExcel中进行,而效应大小的统计分析,双尾p值,研究之间的异质性使用MetaEssentials进行。使用Hedge'sg值在95%置信水平下使用随机效应模型计算效应大小。使用CochraneQ和I2测量研究之间的异质性。
    由PVES弹性印模材料制成的牙科印模在尺寸稳定性方面没有显著变化。浸入化学消毒剂10分钟与PVES印象尺寸的临床无关变化有关。用次氯酸钠消毒与尺寸的临床显着变化有关,双尾p值为0.049。用2-2.5%戊二醛溶液消毒与任何显着的尺寸变异性无关。
    Polyvinyl ether siloxane (PVES) possesses ideal characteristics for making precise and accurate dental impressions. PVES dimensional stability owes to its better polymeric properties derived from its parent materials poly ethers and polyvinyl siloxanes. As recommended use of chemical disinfecting agents is getting more popular, there is a growing concern associated with the effect of disinfectants on PVES dimensional stability. This study was aimed to understand the PVES behavior when subjected to chemical disinfectants.
    The data was collected from research studies retrieved from Google Scholar, Scopus, and PubMed using MeSH terms of keywords \"vinyl polyether siloxane AND Disinfection\" or (Vinyl polyether siloxane OR polyvinyl siloxane ether OR PVES) AND (disinfectant OR disinfection)\" without any restriction to publication date. The PRISMA (Preferred Reporting Items for Systemic Review and Meta-Analysis) directions were observed during the data collection, screening of studies, and meta-analysis. The primary data were retrieved, and batch exported from databases using Harzing\'s Publish or Perish software; primary analysis was performed in Microsoft Excel, while statistical analysis for effect size, two-tailed p-values, and heterogeneity among studies was performed using Meta Essentials. The effect size was calculated using Hedge\'s g values at the 95% confidence level using the random-effects model. Heterogeneity among studies was measured using the Cochrane Q and I2.
    Dental impressions made from the PVES elastomeric impression materials showed no significant changes in dimensional stability. Immersion in the chemical disinfectant for 10 min was associated with clinically irrelevant changes in the dimensions of the PVES impressions. Disinfection with sodium hypochlorite was associated with clinically significant changes in dimensions, with a two-tailed p-value of 0.049. Disinfection with 2-2.5% glutaraldehyde solution was not associated with any significant dimensional variability.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

公众号