本研究的目的是申请和评估跨多媒体挑战的开箱即用的深度学习框架。我们使用从对比度增强的T1 MR到高分辨率T2 MR的域改性的剪切模型。作为数据增强,我们生成了带有较低信号强度的前庭施瓦莫纳的额外图像。对于分段任务,我们使用NNU-Net框架。我们的最终提交在验证阶段实现了0.8299的平均骰子分数,测试阶段0.8253。我们的方法在Crossmoda挑战中排名第3。
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The crossMoDA challenge aims to automatically segment the vestibular schwannoma (VS) tumor and cochlea regions of unlabeled high-resolution T2 scans by leveraging labeled contrast-enhanced T1 scans. The 2022 edition extends the segmentation task by including multi-institutional scans. In this work, we proposed an unpaired cross-modality segmentation framework using data augmentation and hybrid convolutional networks. Considering heterogeneous distributions and various image sizes for multi-institutional scans, we apply the min-max normalization for scaling the intensities of all scans between -1 and 1, and use the voxel size resampling and center cropping to obtain fixed-size sub-volumes for training. We adopt two data augmentation methods for effectively learning the semantic information and generating realistic target domain scans: generative and online data augmentation. For generative data augmentation, we use CUT and CycleGAN to generate two groups of realistic T2 volumes with different details and appearances for supervised segmentation training. For online data augmentation, we design a random tumor signal reducing method for simulating the heterogeneity of VS tumor signals. Furthermore, we utilize an advanced hybrid convolutional network with multi-dimensional convolutions to adaptively learn sparse inter-slice information and dense intra-slice information for accurate volumetric segmentation of VS tumor and cochlea regions in anisotropic scans. On the crossMoDA2022 validation dataset, our method produces promising results and achieves the mean DSC values of 72.47% and 76.48% and ASSD values of 3.42 mm and 0.53 mm for VS tumor and cochlea regions, respectively.
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域适应(DA)最近在医学影像社区提出了强烈的兴趣。虽然已经提出了大量DA技术进行了用于图像分割,但大多数这些技术已经在私有数据集或小公共可用数据集上验证。此外,这些数据集主要解决了单级问题。为了解决这些限制,与第24届医学图像计算和计算机辅助干预(Miccai 2021)结合第24届国际会议组织交叉模态域适应(Crossmoda)挑战。 Crossmoda是无监督跨型号DA的第一个大型和多级基准。挑战的目标是分割参与前庭施瓦新瘤(VS)的后续和治疗规划的两个关键脑结构:VS和Cochleas。目前,使用对比度增强的T1(CET1)MRI进行VS患者的诊断和监测。然而,使用诸如高分辨率T2(HRT2)MRI的非对比度序列越来越感兴趣。因此,我们创建了一个无人监督的跨模型分段基准。训练集提供注释CET1(n = 105)和未配对的非注释的HRT2(n = 105)。目的是在测试集中提供的HRT2上自动对HRT2进行单侧VS和双侧耳蜗分割(n = 137)。共有16支球队提交了评估阶段的算法。顶级履行团队达成的表现水平非常高(最佳中位数骰子 - vs:88.4%; Cochleas:85.7%)并接近完全监督(中位数骰子 - vs:92.5%;耳蜗:87.7%)。所有顶级执行方法都使用图像到图像转换方法将源域图像转换为伪目标域图像。然后使用这些生成的图像和为源图像提供的手动注释进行培训分割网络。
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磁共振图像(MRI)被广泛用于量化前庭切片瘤和耳蜗。最近,深度学习方法显示了用于分割这些结构的最先进的性能。但是,培训细分模型可能需要目标域中的手动标签,这是昂贵且耗时的。为了克服这个问题,域的适应是一种有效的方法,可以利用来自源域的信息来获得准确的分割,而无需在目标域中进行手动标签。在本文中,我们提出了一个无监督的学习框架,以分割VS和耳蜗。我们的框架从对比增强的T1加权(CET1-W)MRI及其标签中利用信息,并为T2加权MRIS产生分割,而目标域中没有任何标签。我们首先应用了一个发电机来实现图像到图像翻译。接下来,我们从不同模型的集合中集合输出以获得最终的分割。为了应对来自不同站点/扫描仪的MRI,我们在培训过程中应用了各种“在线”增强量,以更好地捕获几何变异性以及图像外观和质量的可变性。我们的方法易于构建和产生有希望的分割,在验证集中,VS和耳蜗的平均骰子得分分别为0.7930和0.7432。
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自动分割前庭造型瘤(VS)和来自磁共振成像(MRI)的耳蜗可以促进与治疗计划。无监督的分割方法已显示出令人鼓舞的结果,而无需耗时且费力的手动标记过程。在本文中,我们提出了一种在无监督域的适应设置中进行VS和耳蜗分割的方法。具体而言,我们首先开发了跨站点的跨模式未配对的图像翻译策略,以丰富合成数据的多样性。然后,我们设计了一种基于规则的离线增强技术,以进一步最大程度地减少域间隙。最后,我们采用一个自我训练的自我配置分割框架,以获得最终结果。在Crossmoda 2022验证排行榜上,我们的方法已获得竞争性与耳蜗细分性能,平均骰子得分为0.8178 $ \ pm $ 0.0803和0.8433 $ \ pm $ 0.0293。
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分割前庭施瓦瘤瘤(VS)肿瘤的自动方法和来自磁共振成像(MRI)的耳蜗对VS治疗计划至关重要。虽然监督方法在VS分割中取得了令人满意的性能,但他们需要专家的完整注释,这是费力且耗时的。在这项工作中,我们的目标是在无监督的域适应设置中解决VS和Cochlea分段问题。我们所提出的方法利用了图像级域对齐,以最大限度地减少域发散和半监督培训,以进一步提高性能。此外,我们建议通过嘈杂的标签校正熔断从多个模型预测的标签。我们对挑战验证排行榜的结果表明,我们无人监督的方法取得了有前途的与科技分割性能,平均骰子得分为0.8261 $ \ PM $ 0.0416;肿瘤的平均骰子值为0.8302 $ \ PM $ 0.0772。这与基于弱监督的方法相当。
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对于医学图像分割,想象一下,如果仅使用源域中的MR图像训练模型,它的性能如何直接在目标域中进行CT图像?这种设置,即概括的跨模块分割,拥有其临床潜力,其比其他相关设置更具挑战性,例如域适应。为实现这一目标,我们本文通过利用在我们更广泛的分割期间利用增强的源相似和源不同的图像来提出新的双标准化模块。具体而言,给定单个源域,旨在模拟未经证明的目标域中可能的外观变化,我们首先利用非线性变换来增加源相似和源不同的图像。然后,为了充分利用这两种类型的增强,我们所提出的基于双重定量的模型采用共享骨干但独立的批量归一化层,用于单独归一化。之后,我们提出了一种基于风格的选择方案来自动选择测试阶段的适当路径。在三个公开可用的数据集上进行了广泛的实验,即Brats,跨型心脏和腹部多器官数据集表明我们的方法优于其他最先进的域概括方法。
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这项工作提出了一个新颖的框架CISFA(对比图像合成和自我监督的特征适应),该框架建立在图像域翻译和无监督的特征适应性上,以进行跨模式生物医学图像分割。与现有作品不同,我们使用单方面的生成模型,并在输入图像的采样贴片和相应的合成图像之间添加加权贴片对比度损失,该图像用作形状约束。此外,我们注意到生成的图像和输入图像共享相似的结构信息,但具有不同的方式。因此,我们在生成的图像和输入图像上强制实施对比损失,以训练分割模型的编码器,以最大程度地减少学到的嵌入空间中成对图像之间的差异。与依靠对抗性学习进行特征适应的现有作品相比,这种方法使编码器能够以更明确的方式学习独立于域的功能。我们对包含腹腔和全心的CT和MRI图像的分割任务进行了广泛评估。实验结果表明,所提出的框架不仅输出了较小的器官形状变形的合成图像,而且还超过了最先进的域适应方法的较大边缘。
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Automatic segmentation is essential for the brain tumor diagnosis, disease prognosis, and follow-up therapy of patients with gliomas. Still, accurate detection of gliomas and their sub-regions in multimodal MRI is very challenging due to the variety of scanners and imaging protocols. Over the last years, the BraTS Challenge has provided a large number of multi-institutional MRI scans as a benchmark for glioma segmentation algorithms. This paper describes our contribution to the BraTS 2022 Continuous Evaluation challenge. We propose a new ensemble of multiple deep learning frameworks namely, DeepSeg, nnU-Net, and DeepSCAN for automatic glioma boundaries detection in pre-operative MRI. It is worth noting that our ensemble models took first place in the final evaluation on the BraTS testing dataset with Dice scores of 0.9294, 0.8788, and 0.8803, and Hausdorf distance of 5.23, 13.54, and 12.05, for the whole tumor, tumor core, and enhancing tumor, respectively. Furthermore, the proposed ensemble method ranked first in the final ranking on another unseen test dataset, namely Sub-Saharan Africa dataset, achieving mean Dice scores of 0.9737, 0.9593, and 0.9022, and HD95 of 2.66, 1.72, 3.32 for the whole tumor, tumor core, and enhancing tumor, respectively. The docker image for the winning submission is publicly available at (https://hub.docker.com/r/razeineldin/camed22).
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无监督的域适应性(UDA)是解决一个问题的关键技术之一,很难获得监督学习所需的地面真相标签。通常,UDA假设在培训过程中可以使用来自源和目标域中的所有样本。但是,在涉及数据隐私问题的应用下,这不是现实的假设。为了克服这一限制,最近提出了无源数据的UDA,即无源无监督的域适应性(SFUDA)。在这里,我们提出了一种用于医疗图像分割的SFUDA方法。除了在UDA中通常使用的熵最小化方法外,我们还引入了一个损失函数,以避免目标域中的特征规范和在保留目标器官的形状约束之前。我们使用数据集进行实验,包括多种类型的源目标域组合,以显示我们方法的多功能性和鲁棒性。我们确认我们的方法优于所有数据集中的最先进。
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State-of-the-art brain tumor segmentation is based on deep learning models applied to multi-modal MRIs. Currently, these models are trained on images after a preprocessing stage that involves registration, interpolation, brain extraction (BE, also known as skull-stripping) and manual correction by an expert. However, for clinical practice, this last step is tedious and time-consuming and, therefore, not always feasible, resulting in skull-stripping faults that can negatively impact the tumor segmentation quality. Still, the extent of this impact has never been measured for any of the many different BE methods available. In this work, we propose an automatic brain tumor segmentation pipeline and evaluate its performance with multiple BE methods. Our experiments show that the choice of a BE method can compromise up to 15.7% of the tumor segmentation performance. Moreover, we propose training and testing tumor segmentation models on non-skull-stripped images, effectively discarding the BE step from the pipeline. Our results show that this approach leads to a competitive performance at a fraction of the time. We conclude that, in contrast to the current paradigm, training tumor segmentation models on non-skull-stripped images can be the best option when high performance in clinical practice is desired.
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脾脏是钝性腹腔创伤中最常见的固体器官之一。来自多相CT的自动分割系统的开发用于脾血管损伤的脾血管损伤,可以增强严重程度,以改善临床决策支持和结果预测。然而,由于以下原因,脾血管损伤的准确细分是具有挑战性的:1)脾血管损伤可以是高度变体的形状,质地,尺寸和整体外观; 2)数据采集是一种复杂和昂贵的程序,需要来自数据科学家和放射科学家的密集努力,这使得大规模的注释数据集难以获取。鉴于这些挑战,我们在此设计了一种用于多相脾血管损伤分割的新框架,尤其是数据有限。一方面,我们建议利用外部数据作为矿井伪脾面罩作为空间关注,被称为外部关注,用于引导脾血管损伤的分割。另一方面,我们开发一个合成相位增强模块,它在生成的对抗网络上构建,通过完全利用不同阶段之间的关系来填充内部数据。通过联合实施外部注意力和填充内部数据表示,我们提出的方法优于其他竞争方法,并且在平均DSC方面大大改善了超过7%的流行Deeplab-V3 +基线,这证实了其有效性。
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腹主动脉瘤(AAA)是一种血管疾病,其中主动脉的一部分肿大,削弱其壁并可能破裂血管。腹部超声已用于诊断,但由于其图像质量和操作员的依赖性有限,通常需要进行CT扫描进行监测和治疗计划。最近,腹部CT数据集已成功用于训练深神经网络以进行自动主动脉分割。因此,可以利用从这项解决的任务中收集的知识来改善我们的AAA诊断和监测分段。为此,我们提出了Cactuss:一种常见的解剖CT-US空间,它是CT和美国模式之间的虚拟桥梁,以实现自动AAA筛选超声检查。仙人掌利用公开可用的标记数据来学习基于从美国和CT继承属性的中介表示。我们在此新表示中训练分割网络,并采用附加的图像到图像翻译网络,使我们的模型能够在真实的B模式图像上执行。与完全监督的方法进行的定量比较证明了在骰子评分和诊断指标方面的能力,这表明我们的方法还满足了AAA扫描和诊断的临床要求。
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磁共振成像(MRI)数据由于设备制造商,扫描协议和受试者间变异性的差异而具有异质性。减轻MR图像异质性的一种常规方法是应用预处理转换,例如解剖学比对,体素重新采样,信号强度均衡,图像降解和利益区域的定位(ROI)。尽管预处理管道标准化了图像外观,但其对图像分割质量和深度神经网络(DNN)的其他下游任务的影响从未经过严格研究。在这里,我们报告了一项关于TCIA-GBM开源数据集的多模式MRI MRI脑癌图像分割的全面研究。我们的结果表明,大多数流行的标准化步骤对人工神经网络的性能没有任何价值。此外,预处理可以妨碍模型性能。我们建议,由于信号差异降低了图像标准化,图像强度归一化方法不会导致模型准确性。最后,如果根据临床相关的指标来衡量,我们表明了型型型在数据预处理中的贡献几乎可以忽略不计。我们表明,准确分析的唯一必不可少的转换是整个数据集的体素间距的统一。相反,非刚性地图集注册形式的解剖学对齐不是必需的,大多数强度均衡步骤不能提高模型的生产力。
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实现域适应是有价值的,以将学习知识从标记为CT数据集传输到腹部多器官分段的目标未标记的MR DataSet。同时,非常希望避免目标数据集的高注重成本并保护源数据集的隐私。因此,我们提出了一种有效的无核心无监督域适应方法,用于跨型号腹部多器官分段而不访问源数据集。所提出的框架的过程包括两个阶段。在第一阶段,特征映射统计损失用于对准顶部分段网络中的源和目标特征的分布,并使用熵最小化损耗来鼓励高席位细分。从顶部分段网络输出的伪标签用于指导样式补偿网络生成类似源图像。从中间分割网络输出的伪标签用于监督所需模型的学习(底部分段网络)。在第二阶段,循环学习和像素自适应掩模细化用于进一步提高所需模型的性能。通过这种方法,我们在肝脏,肾脏,左肾肾脏和脾脏的分割中实现了令人满意的性能,骰子相似系数分别为0.884,0.891,0.864和0.911。此外,当存在目标注释数据时,所提出的方法可以很容易地扩展到情况。该性能在平均骰子相似度系数的0.888至0.922增加到0.888至0.922,靠近监督学习(0.929),只有一个标记的MR卷。
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Large annotated datasets are required to train segmentation networks. In medical imaging, it is often difficult, time consuming and expensive to create such datasets, and it may also be difficult to share these datasets with other researchers. Different AI models can today generate very realistic synthetic images, which can potentially be openly shared as they do not belong to specific persons. However, recent work has shown that using synthetic images for training deep networks often leads to worse performance compared to using real images. Here we demonstrate that using synthetic images and annotations from an ensemble of 10 GANs, instead of from a single GAN, increases the Dice score on real test images with 4.7 % to 14.0 % on specific classes.
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While deep learning methods hitherto have achieved considerable success in medical image segmentation, they are still hampered by two limitations: (i) reliance on large-scale well-labeled datasets, which are difficult to curate due to the expert-driven and time-consuming nature of pixel-level annotations in clinical practices, and (ii) failure to generalize from one domain to another, especially when the target domain is a different modality with severe domain shifts. Recent unsupervised domain adaptation~(UDA) techniques leverage abundant labeled source data together with unlabeled target data to reduce the domain gap, but these methods degrade significantly with limited source annotations. In this study, we address this underexplored UDA problem, investigating a challenging but valuable realistic scenario, where the source domain not only exhibits domain shift~w.r.t. the target domain but also suffers from label scarcity. In this regard, we propose a novel and generic framework called ``Label-Efficient Unsupervised Domain Adaptation"~(LE-UDA). In LE-UDA, we construct self-ensembling consistency for knowledge transfer between both domains, as well as a self-ensembling adversarial learning module to achieve better feature alignment for UDA. To assess the effectiveness of our method, we conduct extensive experiments on two different tasks for cross-modality segmentation between MRI and CT images. Experimental results demonstrate that the proposed LE-UDA can efficiently leverage limited source labels to improve cross-domain segmentation performance, outperforming state-of-the-art UDA approaches in the literature. Code is available at: https://github.com/jacobzhaoziyuan/LE-UDA.
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卷积神经网络(CNN)已经实现了医学图像细分的最先进性能,但需要大量的手动注释进行培训。半监督学习(SSL)方法有望减少注释的要求,但是当数据集大小和注释图像的数量较小时,它们的性能仍然受到限制。利用具有类似解剖结构的现有注释数据集来协助培训,这有可能改善模型的性能。然而,由于目标结构的外观不同甚至成像方式,跨解剖结构域的转移进一步挑战。为了解决这个问题,我们提出了跨解剖结构域适应(CS-CADA)的对比度半监督学习,该学习适应一个模型以在目标结构域中细分相似的结构,这仅需要通过利用一组现有现有的现有的目标域中的限制注释源域中相似结构的注释图像。我们使用特定领域的批归归量表(DSBN)来单独地标准化两个解剖域的特征图,并提出跨域对比度学习策略,以鼓励提取域不变特征。它们被整合到一个自我兼容的均值老师(SE-MT)框架中,以利用具有预测一致性约束的未标记的目标域图像。广泛的实验表明,我们的CS-CADA能够解决具有挑战性的跨解剖结构域移位问题,从而在视网膜血管图像和心脏MR图像的帮助下,在X射线图像中准确分割冠状动脉,并借助底底图像,分别仅给定目标域中的少量注释。
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Objective: Thigh muscle group segmentation is important for assessment of muscle anatomy, metabolic disease and aging. Many efforts have been put into quantifying muscle tissues with magnetic resonance (MR) imaging including manual annotation of individual muscles. However, leveraging publicly available annotations in MR images to achieve muscle group segmentation on single slice computed tomography (CT) thigh images is challenging. Method: We propose an unsupervised domain adaptation pipeline with self-training to transfer labels from 3D MR to single CT slice. First, we transform the image appearance from MR to CT with CycleGAN and feed the synthesized CT images to a segmenter simultaneously. Single CT slices are divided into hard and easy cohorts based on the entropy of pseudo labels inferenced by the segmenter. After refining easy cohort pseudo labels based on anatomical assumption, self-training with easy and hard splits is applied to fine tune the segmenter. Results: On 152 withheld single CT thigh images, the proposed pipeline achieved a mean Dice of 0.888(0.041) across all muscle groups including sartorius, hamstrings, quadriceps femoris and gracilis. muscles Conclusion: To our best knowledge, this is the first pipeline to achieve thigh imaging domain adaptation from MR to CT. The proposed pipeline is effective and robust in extracting muscle groups on 2D single slice CT thigh images.The container is available for public use at https://github.com/MASILab/DA_CT_muscle_seg
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多发性硬化症(MS)是中枢神经系统的慢性炎症和退行性疾病,其特征在于,白色和灰质的外观与个体患者的神经症状和标志进行地平整相关。磁共振成像(MRI)提供了详细的体内结构信息,允许定量和分类MS病变,其批判性地通知疾病管理。传统上,MS病变在2D MRI切片上手动注释,一个流程效率低,易于观察室内误差。最近,已经提出了自动统计成像分析技术以基于MRI体素强度检测和分段段病变。然而,它们的有效性受到MRI数据采集技术的异质性和MS病变的外观的限制。通过直接从图像学习复杂的病变表现,深度学习技术已经在MS病变分割任务中取得了显着的突破。在这里,我们提供了全面审查最先进的自动统计和深度学习MS分段方法,并讨论当前和未来的临床应用。此外,我们审查了域适应等技术策略,以增强现实世界临床环境中的MS病变分段。
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