肺部以外的视野(FOV)组织截断在常规的肺筛查计算机断层扫描(CT)中很常见。这对机会性CT的身体组成(BC)评估构成了局限性,因为缺少关键的解剖结构。传统上,扩展CT的FOV被认为是使用有限数据的CT重建问题。但是,这种方法依赖于应用程序中可能无法使用的投影域数据。在这项工作中,我们从语义图像扩展角度提出问题,该角度仅需要图像数据作为输入。提出的两阶段方法根据完整体的估计范围识别新的FOV边框,并在截短区域中渗出了缺失的组织。使用在FOV中具有完整主体的CT切片对训练样品进行模拟,从而使模型开发自制。我们使用有限FOV的肺筛选CT评估了所提出的方法在自动BC评估中的有效性。提出的方法有效地恢复了缺失的组织并减少了FOV组织截断引入的BC评估误差。在大规模肺部筛查CT数据集的BC评估中,这种校正既可以提高受试者内的一致性和与人体测量近似值的相关性。已开发的方法可在https://github.com/masilab/s-efov上获得。
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尽管深度学习预测模型在歧视不同阶层方面已经成功,但它们通常会遭受跨越包括医疗保健在内的具有挑战性领域的校准不良。此外,长尾分布在深度学习分类问题(包括临床疾病预测)中构成了巨大挑战。最近提出了一些方法来校准计算机视觉中的深入预测,但是没有发现代表模型如何在不同挑战性的环境中起作用。在本文中,我们通过对四个高影响力校准模型的比较研究来弥合从计算机视觉到医学成像的置信度校准。我们的研究是在不同的情况下进行的(自然图像分类和肺癌风险估计),包括在平衡与不平衡训练集以及计算机视觉与医学成像中进行。我们的结果支持关键发现:(1)我们获得了新的结​​论,这些结论未在不同的学习环境中进行研究,例如,结合两个校准模型,这些模型都可以减轻过度启发的预测,从而导致了不足的预测,并且来自计算机视觉模型的更简单的校准模型域往往更容易被医学成像化。 (2)我们强调了一般计算机视觉任务和医学成像预测之间的差距,例如,校准方法是通用计算机视觉任务的理想选择,实际上可能会损坏医学成像预测的校准。 (3)我们还加强了自然图像分类设置的先前结论。我们认为,这项研究的优点可以指导读者选择校准模型,并了解一般计算机视觉和医学成像域之间的差距。
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The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.
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To analyze this characteristic of vulnerability, we developed an automated deep learning method for detecting microvessels in intravascular optical coherence tomography (IVOCT) images. A total of 8,403 IVOCT image frames from 85 lesions and 37 normal segments were analyzed. Manual annotation was done using a dedicated software (OCTOPUS) previously developed by our group. Data augmentation in the polar (r,{\theta}) domain was applied to raw IVOCT images to ensure that microvessels appear at all possible angles. Pre-processing methods included guidewire/shadow detection, lumen segmentation, pixel shifting, and noise reduction. DeepLab v3+ was used to segment microvessel candidates. A bounding box on each candidate was classified as either microvessel or non-microvessel using a shallow convolutional neural network. For better classification, we used data augmentation (i.e., angle rotation) on bounding boxes with a microvessel during network training. Data augmentation and pre-processing steps improved microvessel segmentation performance significantly, yielding a method with Dice of 0.71+/-0.10 and pixel-wise sensitivity/specificity of 87.7+/-6.6%/99.8+/-0.1%. The network for classifying microvessels from candidates performed exceptionally well, with sensitivity of 99.5+/-0.3%, specificity of 98.8+/-1.0%, and accuracy of 99.1+/-0.5%. The classification step eliminated the majority of residual false positives, and the Dice coefficient increased from 0.71 to 0.73. In addition, our method produced 698 image frames with microvessels present, compared to 730 from manual analysis, representing a 4.4% difference. When compared to the manual method, the automated method improved microvessel continuity, implying improved segmentation performance. The method will be useful for research purposes as well as potential future treatment planning.
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由于其高质量的重建以及将现有迭代求解器结合起来的易于性,因此最近将扩散模型作为强大的生成反问题解决器研究。但是,大多数工作都专注于在无噪声设置中解决简单的线性逆问题,这显着不足以使实际问题的复杂性不足。在这项工作中,我们将扩散求解器扩展求解器,以通过后采样的拉普拉斯近似有效地处理一般噪声(非)线性反问题。有趣的是,所得的后验采样方案是扩散采样的混合版本,具有歧管约束梯度,而没有严格的测量一致性投影步骤,与先前的研究相比,在嘈杂的设置中产生了更可取的生成路径。我们的方法表明,扩散模型可以结合各种测量噪声统计量,例如高斯和泊松,并且还有效处理嘈杂的非线性反问题,例如傅立叶相检索和不均匀的脱毛。
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从单个放射学图像中学到的功能无法提供有关随着时间的流逝可能发生的病变以及多少变化的信息。从重复图像计算出的时间相关特征可以捕获这些变化,并通过其时间行为来识别恶性病变。但是,纵向医学成像提出了数据获取的稀疏,不规则时间间隔的独特挑战。虽然自我注意事项已被证明是时间序列和自然图像的一种多功能,有效的学习机制,但尚未探索其在稀疏,不规则采样的空​​间特征之间解释时间距离的潜力。在这项工作中,我们通过使用(1)连续时间的矢量嵌入和(2)时间强调自我注意力的权重来提出两种解释时间距离视觉变压器(VIT)。这两种算法是根据合成肺结节的良性与恶性肺癌区分和肺筛查计算机断层扫描研究(NLST)评估的。与标准VIT相比,评估合成结节的时间段VIT的实验表明,在对不规则采样的纵向图像进行分类方面有了基本改进。在从NLST筛选胸部CTS的交叉验证中,我们的方法(分别为0.785和0.786 AUC)显着超过了横截面方法(0.734 AUC)(0.734 AUC),并匹配领先的纵向医学成像算法(0.779 AUC)在良好的良性上的判别性能与恶性分类。这项工作代表了第一个基于自我注意的框架,用于对纵向医学图像进行分类。我们的代码可从https://github.com/tom1193/time-distance-transformer获得。
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子痫前期是孕产妇和胎儿发病率和死亡率的主要原因。目前,先兆子痫的唯一明确治疗方法是胎盘的递送,这对于疾病的发病机理至关重要。已经广泛地进行了鉴定出差异表达的基因(DEGS),已经进行了广泛的先兆子痫对人胎盘的转录分析。使用无偏见的测定法确定了DEG,但是,在实验上研究DEG的决策受到许多因素的偏见,导致许多DEGS仍未被评估。一组与疾病在实验上相关的DEG,但与文献中的疾病尚无相关性,被称为无知组。先兆子痫具有广泛的科学文献,大量的DEG数据库,只有一种确定的治疗方法。促进基于知识的分析的工具能够将许多来源的不同数据结合起来,以提出基本的行动机制,可能是支持发现并提高我们对这种疾病的理解的宝贵资源。在这项工作中,我们证明了如何使用生物医学知识图(KG)来识别新型的先兆子痫分子机制。现有的开源生物医学资源和公开可用的高通量转录分析数据用于识别和注释当前未经资助的先兆子痫相关的DEG的功能。使用文本挖掘方法从PubMed摘要中鉴定出与先兆子痫相关的基因。文本媒介和荟萃分析衍生的列表的相对补体被确定为未经投票的前启示性脱位相关的DEG(n = 445),即先前的无知组。使用KG研究相关的DEG,揭示了53种新型临床相关和生物学作用的机械关联。
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Majorana示威者是一项领先的实验,寻找具有高纯净锗探测器(HPGE)的中性s中性双β衰变。机器学习提供了一种最大化这些检测器提供的信息量的新方法,但是与传统分析相比,数据驱动的性质使其不可解释。一项可解释性研究揭示了机器的决策逻辑,使我们能够从机器中学习以反馈传统分析。在这项工作中,我们介绍了Majorana演示者数据的第一个机器学习分析。这也是对任何锗探测器实验的第一个可解释的机器学习分析。训练了两个梯度增强的决策树模型,以从数据中学习,并进行了基于游戏理论的模型可解释性研究,以了解分类功率的起源。通过从数据中学习,该分析识别重建参数之间的相关性,以进一步增强背景拒绝性能。通过从机器中学习,该分析揭示了新的背景类别对相互利用的标准Majorana分析的重要性。该模型与下一代锗探测器实验(如传说)高度兼容,因为它可以同时在大量探测器上进行训练。
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语言模型既展示了定量的改进,又展示了新的定性功能,随着规模的增加。尽管它们具有潜在的变革性影响,但这些新能力的特征却很差。为了为未来的研究提供信息,为破坏性的新模型能力做准备,并改善社会有害的效果,至关重要的是,我们必须了解目前和近乎未来的能力和语言模型的局限性。为了应对这一挑战,我们介绍了超越模仿游戏基准(Big Bench)。 Big Bench目前由204个任务组成,由132家机构的442位作者贡献。任务主题是多样的,从语言学,儿童发展,数学,常识性推理,生物学,物理学,社会偏见,软件开发等等。 Big-Bench专注于被认为超出当前语言模型的功能的任务。我们评估了OpenAI的GPT型号,Google内部密集变压器体系结构和大型基础上的开关稀疏变压器的行为,跨越了数百万到数十亿个参数。此外,一个人类专家评估者团队执行了所有任务,以提供强大的基准。研究结果包括:模型性能和校准都随规模改善,但绝对的术语(以及与评估者的性能相比);在模型类中的性能非常相似,尽管带有稀疏性。逐渐和预测的任务通常涉及大量知识或记忆成分,而在临界规模上表现出“突破性”行为的任务通常涉及多个步骤或组成部分或脆性指标;社交偏见通常会随着含糊不清的环境而随着规模而增加,但这可以通过提示来改善。
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Thin-cap fibroatheroma (TCFA) and plaque rupture have been recognized as the most frequent risk factor for thrombosis and acute coronary syndrome. Intravascular optical coherence tomography (IVOCT) can identify TCFA and assess cap thickness, which provides an opportunity to assess plaque vulnerability. We developed an automated method that can detect lipidous plaque and assess fibrous cap thickness in IVOCT images. This study analyzed a total of 4,360 IVOCT image frames of 77 lesions among 41 patients. To improve segmentation performance, preprocessing included lumen segmentation, pixel-shifting, and noise filtering on the raw polar (r, theta) IVOCT images. We used the DeepLab-v3 plus deep learning model to classify lipidous plaque pixels. After lipid detection, we automatically detected the outer border of the fibrous cap using a special dynamic programming algorithm and assessed the cap thickness. Our method provided excellent discriminability of lipid plaque with a sensitivity of 85.8% and A-line Dice coefficient of 0.837. By comparing lipid angle measurements between two analysts following editing of our automated software, we found good agreement by Bland-Altman analysis (difference 6.7+/-17 degree; mean 196 degree). Our method accurately detected the fibrous cap from the detected lipid plaque. Automated analysis required a significant modification for only 5.5% frames. Furthermore, our method showed a good agreement of fibrous cap thickness between two analysts with Bland-Altman analysis (4.2+/-14.6 micron; mean 175 micron), indicating little bias between users and good reproducibility of the measurement. We developed a fully automated method for fibrous cap quantification in IVOCT images, resulting in good agreement with determinations by analysts. The method has great potential to enable highly automated, repeatable, and comprehensive evaluations of TCFAs.
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