2D低剂量单板腹部计算机断层扫描(CT)切片可直接测量身体成分,这对于对衰老的健康关系进行定量表征至关重要。然而,由于不同年内获得的纵向切片之间的位置方差,使用2D腹部切片对人体成分变化的纵向分析具有挑战性。为了减少位置差异,我们将条件生成模型扩展到我们的C-斜肌,该模型在腹部区域进行任意轴向切片作为条件,并通过估计潜在空间的结构变化来生成定义的椎骨水平切片。对来自内部数据集的1170名受试者的实验和BTCV Miccai挑战赛的50名受试者的实验表明,我们的模型可以从现实主义和相似性方面产生高质量的图像。来自巴尔的摩纵向研究(BLSA)数据集的20名受试者的外部实验,其中包含纵向单腹部切片验证了我们的方法可以在肌肉和内脏脂肪面积方面与切片的位置方差进行协调。我们的方法提供了一个有希望的方向,将切片从不同的椎骨水平映射到目标切片,以减少单个切片纵向分析的位置差异。源代码可在以下网址获得:https://github.com/masilab/c-slicegen。
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Transformer-based models, capable of learning better global dependencies, have recently demonstrated exceptional representation learning capabilities in computer vision and medical image analysis. Transformer reformats the image into separate patches and realize global communication via the self-attention mechanism. However, positional information between patches is hard to preserve in such 1D sequences, and loss of it can lead to sub-optimal performance when dealing with large amounts of heterogeneous tissues of various sizes in 3D medical image segmentation. Additionally, current methods are not robust and efficient for heavy-duty medical segmentation tasks such as predicting a large number of tissue classes or modeling globally inter-connected tissues structures. Inspired by the nested hierarchical structures in vision transformer, we proposed a novel 3D medical image segmentation method (UNesT), employing a simplified and faster-converging transformer encoder design that achieves local communication among spatially adjacent patch sequences by aggregating them hierarchically. We extensively validate our method on multiple challenging datasets, consisting anatomies of 133 structures in brain, 14 organs in abdomen, 4 hierarchical components in kidney, and inter-connected kidney tumors). We show that UNesT consistently achieves state-of-the-art performance and evaluate its generalizability and data efficiency. Particularly, the model achieves whole brain segmentation task complete ROI with 133 tissue classes in single network, outperforms prior state-of-the-art method SLANT27 ensembled with 27 network tiles, our model performance increases the mean DSC score of the publicly available Colin and CANDI dataset from 0.7264 to 0.7444 and from 0.6968 to 0.7025, respectively.
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从心脏病学到神经病学的疾病中,代谢健康越来越多地成为危险因素,身体成分的效率评估对于定量表征这些关系至关重要。 2D低剂量单切层扫描术(CT)提供了高分辨率,定量组织图,尽管视野有限。尽管在量化图像上下文时已经提出了许多潜在的分析,但尚无对低剂量单切片CT纵向变异性进行自动分割的全面研究。我们使用受监督的基于深度学习的细分和无监督的聚类方法研究了1469个巴尔的摩纵向研究(BLSA)腹部数据集的1469名纵向研究(BLSA)腹部数据集的1816片。在前两次扫描中有两年差距的1469名受试者中有300名被选出,以评估纵向变异性,其中包括类内相关系数(ICC)和变异系数(CV),以组织/器官的大小和平均强度为单位。我们表明,我们的分割方法在纵向环境中是稳定的,骰子范围为13个目标腹部组织结构的0.821至0.962。我们观察到ICC <0.5的大多数器官的较高变异性,肌肉,腹壁,脂肪和体膜的变化较低,平均ICC> 0.8。我们发现器官的变异性与2D切片的横截面位置高度相关。我们的努力铺平了定量探索和质量控制,以减少纵向分析中的不确定性。
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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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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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In this paper, we study the problem of knowledge-intensive text-to-SQL, in which domain knowledge is necessary to parse expert questions into SQL queries over domain-specific tables. We formalize this scenario by building a new Chinese benchmark KnowSQL consisting of domain-specific questions covering various domains. We then address this problem by presenting formulaic knowledge, rather than by annotating additional data examples. More concretely, we construct a formulaic knowledge bank as a domain knowledge base and propose a framework (ReGrouP) to leverage this formulaic knowledge during parsing. Experiments using ReGrouP demonstrate a significant 28.2% improvement overall on KnowSQL.
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Weakly-supervised object localization aims to indicate the category as well as the scope of an object in an image given only the image-level labels. Most of the existing works are based on Class Activation Mapping (CAM) and endeavor to enlarge the discriminative area inside the activation map to perceive the whole object, yet ignore the co-occurrence confounder of the object and context (e.g., fish and water), which makes the model inspection hard to distinguish object boundaries. Besides, the use of CAM also brings a dilemma problem that the classification and localization always suffer from a performance gap and can not reach their highest accuracy simultaneously. In this paper, we propose a casual knowledge distillation method, dubbed KD-CI-CAM, to address these two under-explored issues in one go. More specifically, we tackle the co-occurrence context confounder problem via causal intervention (CI), which explores the causalities among image features, contexts, and categories to eliminate the biased object-context entanglement in the class activation maps. Based on the de-biased object feature, we additionally propose a multi-teacher causal distillation framework to balance the absorption of classification knowledge and localization knowledge during model training. Extensive experiments on several benchmarks demonstrate the effectiveness of KD-CI-CAM in learning clear object boundaries from confounding contexts and addressing the dilemma problem between classification and localization performance.
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Dynamic treatment regimes assign personalized treatments to patients sequentially over time based on their baseline information and time-varying covariates. In mobile health applications, these covariates are typically collected at different frequencies over a long time horizon. In this paper, we propose a deep spectral Q-learning algorithm, which integrates principal component analysis (PCA) with deep Q-learning to handle the mixed frequency data. In theory, we prove that the mean return under the estimated optimal policy converges to that under the optimal one and establish its rate of convergence. The usefulness of our proposal is further illustrated via simulations and an application to a diabetes dataset.
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Nowadays, time-stamped web documents related to a general news query floods spread throughout the Internet, and timeline summarization targets concisely summarizing the evolution trajectory of events along the timeline. Unlike traditional document summarization, timeline summarization needs to model the time series information of the input events and summarize important events in chronological order. To tackle this challenge, in this paper, we propose a Unified Timeline Summarizer (UTS) that can generate abstractive and extractive timeline summaries in time order. Concretely, in the encoder part, we propose a graph-based event encoder that relates multiple events according to their content dependency and learns a global representation of each event. In the decoder part, to ensure the chronological order of the abstractive summary, we propose to extract the feature of event-level attention in its generation process with sequential information remained and use it to simulate the evolutionary attention of the ground truth summary. The event-level attention can also be used to assist in extracting summary, where the extracted summary also comes in time sequence. We augment the previous Chinese large-scale timeline summarization dataset and collect a new English timeline dataset. Extensive experiments conducted on these datasets and on the out-of-domain Timeline 17 dataset show that UTS achieves state-of-the-art performance in terms of both automatic and human evaluations.
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