使用相对比心脏磁共振成像(PC-CMR)进行的流量分析可以量化用于评估心血管功能的重要参数。该分析的重要部分是鉴定正确的CMR视图和质量控制(QC),以检测可能影响流量定量的伪像。我们提出了一个新型的基于深度学习的框架,用于对完整CMR扫描的流量进行完全自动化的分析,该框架首先使用两个顺序卷积神经网络进行这些视图选择和QC步骤,然后进行自动主动脉和肺动脉分段,以实现对量化的量化。钥匙流参数。对于观察分类和QC,获得了0.958和0.914的精度值。对于细分,骰子分数为$> $ 0.969,而平淡的altman情节表示手动和自动峰流量值之间的一致性很高。此外,我们在外部验证数据集上测试了管道,结果表明管道的鲁棒性。这项工作是使用由986例病例组成的多生临床数据进行的,表明在临床环境中使用该管道的潜力。
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简介:人工智能(AI)有可能促进CMR分析以进行生物标志物提取的自动化。但是,大多数AI算法都经过特定输入域(例如单扫描仪供应商或医院量化成像协议)的培训,并且当从其他输入域中应用于CMR数据时,缺乏最佳性能的鲁棒性。方法:我们提出的框架包括一种基于AI的算法,用于对短轴图像的双脑室分割,然后进行分析后质量控制,以检测错误的结果。分割算法在来自两家NHS医院(n = 2793)的大型临床CMR扫描数据集上进行了培训,并在此数据集(n = 441)和五个外部数据集(n = 6808)上进行了验证。验证数据包括使用所有主要供应商的CMR扫描仪在12个不同中心获得的一系列疾病的患者的CMR扫描。结果:我们的方法产生的中位骰子得分超过87%,转化为观察者间变异范围内心脏生物标志物中的中值绝对错误:<8.4ml(左心室),<9.2ml(右心室),<13.3G(左心室),<13.3G(左心室所有数据集的心室质量),<5.9%(射血分数)。根据心脏疾病和扫描仪供应商的表型的病例分层显示出良好的一致性。结论:我们表明,我们提出的工具结合了在大规模多域CMR数据集中训练的最先进的AI算法和分析后质量控制,使我们能够从多个中心,供应商和心脏病。这是AI算法临床翻译的基本步骤。此外,我们的方法以无需额外的计算成本而产生一系列心脏功能(填充和弹出率,区域壁运动和应变)的附加生物标志物。
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左心室(LV)功能是心脏病患者的患者管理,结局和长期存活方面的重要因素。最近发表的心力衰竭临床指南认识到,仅依赖一种心脏功能(LV射血分数)作为诊断和治疗分层生物标志物的依赖是次优。基于AI的超声心动图分析的最新进展已在LV体积和LV射血分数的自动估计上显示出良好的结果。但是,从随时间变化的2D超声心动图摄取,可以通过从完整的心脏周期中估算功能性生物标志物来获得对心脏功能的更丰富的描述。在这项工作中,我们首次提出了一种基于全心脏周期分割的2D超声心动图的AI方法,用于从2D超声心动图中得出高级生物标志物。这些生物标志物将允许临床医生获得健康和疾病中心脏的丰富图片。 AI模型基于“ NN-UNET”框架,并使用四个不同的数据库进行了训练和测试。结果表明,手动分析和自动分析之间的一致性很高,并展示了晚期收缩期和舒张期生物标志物在患者分层中的潜力。最后,对于50例病例的子集,我们在超声心动图和CMR的临床生物标志物之间进行了相关分析,我们在两种方式之间表现出了极好的一致性。
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Compared to regular cameras, Dynamic Vision Sensors or Event Cameras can output compact visual data based on a change in the intensity in each pixel location asynchronously. In this paper, we study the application of current image-based SLAM techniques to these novel sensors. To this end, the information in adaptively selected event windows is processed to form motion-compensated images. These images are then used to reconstruct the scene and estimate the 6-DOF pose of the camera. We also propose an inertial version of the event-only pipeline to assess its capabilities. We compare the results of different configurations of the proposed algorithm against the ground truth for sequences of two publicly available event datasets. We also compare the results of the proposed event-inertial pipeline with the state-of-the-art and show it can produce comparable or more accurate results provided the map estimate is reliable.
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The purpose of this work was to tackle practical issues which arise when using a tendon-driven robotic manipulator with a long, passive, flexible proximal section in medical applications. A separable robot which overcomes difficulties in actuation and sterilization is introduced, in which the body containing the electronics is reusable and the remainder is disposable. A control input which resolves the redundancy in the kinematics and a physical interpretation of this redundancy are provided. The effect of a static change in the proximal section angle on bending angle error was explored under four testing conditions for a sinusoidal input. Bending angle error increased for increasing proximal section angle for all testing conditions with an average error reduction of 41.48% for retension, 4.28% for hysteresis, and 52.35% for re-tension + hysteresis compensation relative to the baseline case. Two major sources of error in tracking the bending angle were identified: time delay from hysteresis and DC offset from the proximal section angle. Examination of these error sources revealed that the simple hysteresis compensation was most effective for removing time delay and re-tension compensation for removing DC offset, which was the primary source of increasing error. The re-tension compensation was also tested for dynamic changes in the proximal section and reduced error in the final configuration of the tip by 89.14% relative to the baseline case.
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Transformers have recently gained attention in the computer vision domain due to their ability to model long-range dependencies. However, the self-attention mechanism, which is the core part of the Transformer model, usually suffers from quadratic computational complexity with respect to the number of tokens. Many architectures attempt to reduce model complexity by limiting the self-attention mechanism to local regions or by redesigning the tokenization process. In this paper, we propose DAE-Former, a novel method that seeks to provide an alternative perspective by efficiently designing the self-attention mechanism. More specifically, we reformulate the self-attention mechanism to capture both spatial and channel relations across the whole feature dimension while staying computationally efficient. Furthermore, we redesign the skip connection path by including the cross-attention module to ensure the feature reusability and enhance the localization power. Our method outperforms state-of-the-art methods on multi-organ cardiac and skin lesion segmentation datasets without requiring pre-training weights. The code is publicly available at https://github.com/mindflow-institue/DAEFormer.
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A track-before-detect (TBD) particle filter-based method for detection and tracking of low observable objects based on a sequence of image frames in the presence of noise and clutter is studied. At each time instance after receiving a frame of image, first, some preprocessing approaches are applied to the image. Then, it is sent to the detection and tracking algorithm which is based on a particle filter. Performance of the approach is evaluated for detection and tracking of an object in different scenarios including noise and clutter.
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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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Machine reading comprehension (MRC) is a long-standing topic in natural language processing (NLP). The MRC task aims to answer a question based on the given context. Recently studies focus on multi-hop MRC which is a more challenging extension of MRC, which to answer a question some disjoint pieces of information across the context are required. Due to the complexity and importance of multi-hop MRC, a large number of studies have been focused on this topic in recent years, therefore, it is necessary and worth reviewing the related literature. This study aims to investigate recent advances in the multi-hop MRC approaches based on 31 studies from 2018 to 2022. In this regard, first, the multi-hop MRC problem definition will be introduced, then 31 models will be reviewed in detail with a strong focus on their multi-hop aspects. They also will be categorized based on their main techniques. Finally, a fine-grain comprehensive comparison of the models and techniques will be presented.
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Multi-hop Machine reading comprehension is a challenging task with aim of answering a question based on disjoint pieces of information across the different passages. The evaluation metrics and datasets are a vital part of multi-hop MRC because it is not possible to train and evaluate models without them, also, the proposed challenges by datasets often are an important motivation for improving the existing models. Due to increasing attention to this field, it is necessary and worth reviewing them in detail. This study aims to present a comprehensive survey on recent advances in multi-hop MRC evaluation metrics and datasets. In this regard, first, the multi-hop MRC problem definition will be presented, then the evaluation metrics based on their multi-hop aspect will be investigated. Also, 15 multi-hop datasets have been reviewed in detail from 2017 to 2022, and a comprehensive analysis has been prepared at the end. Finally, open issues in this field have been discussed.
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