Automated identification of myocardial scar from late gadolinium enhancement cardiac magnetic resonance images (LGE-CMR) is limited by image noise and artifacts such as those related to motion and partial volume effect. This paper presents a novel joint deep learning (JDL) framework that improves such tasks by utilizing simultaneously learned myocardium segmentations to eliminate negative effects from non-region-of-interest areas. In contrast to previous approaches treating scar detection and myocardium segmentation as separate or parallel tasks, our proposed method introduces a message passing module where the information of myocardium segmentation is directly passed to guide scar detectors. This newly designed network will efficiently exploit joint information from the two related tasks and use all available sources of myocardium segmentation to benefit scar identification. We demonstrate the effectiveness of JDL on LGE-CMR images for automated left ventricular (LV) scar detection, with great potential to improve risk prediction in patients with both ischemic and non-ischemic heart disease and to improve response rates to cardiac resynchronization therapy (CRT) for heart failure patients. Experimental results show that our proposed approach outperforms multiple state-of-the-art methods, including commonly used two-step segmentation-classification networks, and multitask learning schemes where subtasks are indirectly interacted.
translated by 谷歌翻译
The selection of an optimal pacing site, which is ideally scar-free and late activated, is critical to the response of cardiac resynchronization therapy (CRT). Despite the success of current approaches formulating the detection of such late mechanical activation (LMA) regions as a problem of activation time regression, their accuracy remains unsatisfactory, particularly in cases where myocardial scar exists. To address this issue, this paper introduces a multi-task deep learning framework that simultaneously estimates LMA amount and classify the scar-free LMA regions based on cine displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI). With a newly introduced auxiliary LMA region classification sub-network, our proposed model shows more robustness to the complex pattern cause by myocardial scar, significantly eliminates their negative effects in LMA detection, and in turn improves the performance of scar classification. To evaluate the effectiveness of our method, we tests our model on real cardiac MR images and compare the predicted LMA with the state-of-the-art approaches. It shows that our approach achieves substantially increased accuracy. In addition, we employ the gradient-weighted class activation mapping (Grad-CAM) to visualize the feature maps learned by all methods. Experimental results suggest that our proposed model better recognizes the LMA region pattern.
translated by 谷歌翻译
运营商网络已成为有希望的深度学习工具,用于近似偏微分方程(PDE)的解决方案。这些网络绘制了描述材料属性,迫使函数和边界数据的输入函数到PDE解决方案。这项工作描述了一种针对操作员网络的新体系结构,该架构模仿了从问题的变异公式或弱公式中获得的数值解决方案的形式。这些想法在通用椭圆的PDE中的应用导致变异模拟操作员网络(Varmion)。像常规的深层操作员网络(DeepOnet)一样,Varmion也由一个子网络组成,该子网络构建了输出的基础函数,另一个构造了这些基础函数系数的基本功能。但是,与deponet相反,在Varmion中,这些网络的体系结构是精确确定的。对Varmion解决方案中误差的分析表明,它包含训练数据中的误差,训练错误,抽样输入中的正交误差和输出功能的贡献,以及测量测试输入功能之间距离的“覆盖错误”以及培训数据集中最近的功能。这也取决于确切网络及其varmion近似的稳定性常数。 Varmion在规范椭圆形PDE中的应用表明,对于大约相同数量的网络参数,平均而言,Varmion的误差比标准DeepOnet较小。此外,其性能对于输入函数的变化,用于采样输入和输出功能的技术,用于构建基本函数的技术以及输入函数的数量更为强大。
translated by 谷歌翻译
联合学习(FL)是一种分布式机器学习技术,可以在避免明确的数据共享的同时进行协作模型培训。 FL算法的固有保护属性使其对医疗领域特别有吸引力。但是,如果有异质的客户数据分布,则标准FL方法是不稳定的,需要密集的超参数调整以实现最佳性能。常规的超参数优化算法在现实世界中的FL应用中是不切实际的,因为它们涉及大量的培训试验,而计算预算有限,这些试验通常是不起作用的。在这项工作中,我们提出了一种有效的增强学习(RL)的联合次数超参数优化算法,称为自动FEDRL,其中在线RL代理可以根据当前的培训进度动态调整每个客户的超参数。进行了广泛的实验以研究不同的搜索策略和RL代理。该方法的有效性在CIFAR-10数据集的异质数据分配以及两个现实世界中的医学图像分割数据集上进行了验证,用于胸部CT中的COVID-19变病变分段,腹部CT中的胰腺细分。
translated by 谷歌翻译
为医学图像评估构建准确和强大的人工智能系统,不仅需要高级深度学习模型的研究和设计,还需要创建大型和策划的注释训练示例。然而,构造这种数据集通常非常昂贵 - 由于注释任务的复杂性和解释医学图像所需的高度专业知识(例如,专家放射科医师)。为了对此限制来说,我们提出了一种基于对比学习和在线特征聚类的丰富图像特征自我监督学习方法。为此目的,我们利用各种方式的大超过100,000,000个医学图像的大型训练数据集,包括放射线照相,计算机断层扫描(CT),磁共振(MR)成像和超声检查。我们建议使用这些功能来指导在各种下游任务的监督和混合自我监督/监督制度的模型培训。我们突出了这种策略对射线照相,CT和MR:1的挑战性图像评估问题的许多优点,与最先进的(例如,检测3-7%的AUC升压为3-7%胸部射线照相扫描的异常和脑CT的出血检测); 2)与使用无预先训练(例如,83%,在培训MR扫描MR扫描中的脑转移的模型时,在训练期间训练期间的模型收敛在训练期间的培训期高达85%。 3)对各种图像增强的鲁棒性增加,例如在场中看到的数据变化的强度变化,旋转或缩放反射。
translated by 谷歌翻译
深度学习(DL)模型为各种医学成像基准挑战提供了最先进的性能,包括脑肿瘤细分(BRATS)挑战。然而,局灶性病理多隔室分割(例如,肿瘤和病变子区)的任务特别具有挑战性,并且潜在的错误阻碍DL模型转化为临床工作流程。量化不确定形式的DL模型预测的可靠性,可以实现最不确定的地区的临床审查,从而建立信任并铺平临床翻译。最近,已经引入了许多不确定性估计方法,用于DL医学图像分割任务。开发指标评估和比较不确定性措施的表现将有助于最终用户制定更明智的决策。在本研究中,我们探索并评估在Brats 2019-2020任务期间开发的公制,以对不确定量化量化(Qu-Brats),并旨在评估和排列脑肿瘤多隔室分割的不确定性估计。该公制(1)奖励不确定性估计,对正确断言产生高置信度,以及在不正确的断言处分配低置信水平的估计数,(2)惩罚导致更高百分比的无关正确断言百分比的不确定性措施。我们进一步基准测试由14个独立参与的Qu-Brats 2020的分割不确定性,所有这些都参与了主要的Brats细分任务。总体而言,我们的研究结果证实了不确定性估计提供了分割算法的重要性和互补价值,因此突出了医学图像分析中不确定性量化的需求。我们的评估代码在HTTPS://github.com/ragmeh11/qu-brats公开提供。
translated by 谷歌翻译
Colorsseum是一种开放式和公开可用的大型无线无线测试,可通过虚拟化和软载波形和协议堆栈进行实验研究,在完全可编程的“白盒子”平台上。通过256最先进的软件定义的无线电和巨大的通道仿真器核心,罗马斗兽场几乎可以模拟任何方案,在各种部署和渠道条件下,可以在规模上进行设计,开发和测试解决方案。通过有限脉冲响应滤波器通过高保真FPGA的仿真再现这些罗马孔射频场景。过滤器模拟所需的无线通道的抽头,并将它们应用于无线电节点生成的信号,忠实地模拟现实世界无线环境的条件。在本文中,我们将罗马斗兽场介绍为测试楼,这是第一次向研究界开放。我们描述了罗马斗兽场的建筑及其实验和仿真能力。然后,我们通过示例性用例证明了罗马斗兽场对实验研究的有效性,包括频谱共享和无人空中车辆场景的普遍用途用例,包括普遍的无线技术(例如,蜂窝和Wi-Fi)。斗兽索斗兽场未来更新的路线图总结了这篇论文。
translated by 谷歌翻译
最近,提出了不变的风险最小化(IRM)作为解决分布外(OOD)概括的有前途的解决方案。但是,目前尚不清楚何时应优先于广泛的经验风险最小化(ERM)框架。在这项工作中,我们从样本复杂性的角度分析了这两个框架,从而迈出了一个坚定的一步,以回答这个重要问题。我们发现,根据数据生成机制的类型,这两种方法可能具有有限样本和渐近行为。例如,在协变量偏移设置中,我们看到两种方法不仅达到了相同的渐近解决方案,而且具有相似的有限样本行为,没有明显的赢家。但是,对于其他分布变化,例如涉及混杂因素或反毒物变量的变化,两种方法到达不同的渐近解决方案,在这些方法中,保证IRM可以接近有限样品状态中所需的OOD溶液,而ERM甚至偶然地偏向于渐近。我们进一步研究了不同因素(环境的数量,模型的复杂性和IRM惩罚权重)如何影响IRM的样本复杂性与其距离OOD溶液的距离有关
translated by 谷歌翻译
The recent increase in public and academic interest in preserving biodiversity has led to the growth of the field of conservation technology. This field involves designing and constructing tools that utilize technology to aid in the conservation of wildlife. In this article, we will use case studies to demonstrate the importance of designing conservation tools with human-wildlife interaction in mind and provide a framework for creating successful tools. These case studies include a range of complexities, from simple cat collars to machine learning and game theory methodologies. Our goal is to introduce and inform current and future researchers in the field of conservation technology and provide references for educating the next generation of conservation technologists. Conservation technology not only has the potential to benefit biodiversity but also has broader impacts on fields such as sustainability and environmental protection. By using innovative technologies to address conservation challenges, we can find more effective and efficient solutions to protect and preserve our planet's resources.
translated by 谷歌翻译
A Digital Twin (DT) is a simulation of a physical system that provides information to make decisions that add economic, social or commercial value. The behaviour of a physical system changes over time, a DT must therefore be continually updated with data from the physical systems to reflect its changing behaviour. For resource-constrained systems, updating a DT is non-trivial because of challenges such as on-board learning and the off-board data transfer. This paper presents a framework for updating data-driven DTs of resource-constrained systems geared towards system health monitoring. The proposed solution consists of: (1) an on-board system running a light-weight DT allowing the prioritisation and parsimonious transfer of data generated by the physical system; and (2) off-board robust updating of the DT and detection of anomalous behaviours. Two case studies are considered using a production gas turbine engine system to demonstrate the digital representation accuracy for real-world, time-varying physical systems.
translated by 谷歌翻译