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

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。

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.

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。

多发性硬化症（MS）是一种慢性神经炎症性疾病，多模态MRIS通常用于监测MS病变。许多自动MS病变细分模型已经开发并达到了人类水平的性能。但是，大多数已建立的方法都假定在训练过程中使用的MRI模式在测试过程中也可以使用，这在临床实践中不能保证。以前，已将称为模式辍学的训练策略应用于MS病变细分，以实现最先进的性能，而缺失了模态。在本文中，我们提出了一种称为ModDrop ++的新方法，以训练统一的网络适应于任意数量的输入MRI序列。 ModDrop ++以两种关键方式升级ModDrop的主要思想。首先，我们设计一个插件动态头，并采用过滤器缩放策略来提高网络的表现力。其次，我们设计了一种共同训练策略，以利用完全模态和缺失方式之间的主体内关系。具体而言，主体内共同训练策略旨在指导动态头部在同一主题的全模式数据和缺失模式数据之间生成相似的特征表示。我们使用两个公共MS数据集来显示ModDrop ++的优势。源代码和训练有素的模型可在https://github.com/han-liu/moddropplusplus上获得。

医学图像分割或计算voxelwise语义面具是一个基本又具有挑战性的任务，用于计算体素级语义面具。为了提高编码器 - 解码器神经网络在大型临床队列中执行这项任务的能力，对比学习提供了稳定模型初始化和增强编码器而无需标签的机会。然而，多个目标对象（具有不同的语义含义）可能存在于单个图像中，这使得适应传统的对比学习方法从普遍的“图像级分类”到“像素级分段”中的问题。在本文中，我们提出了一种简单的语义感知对比学习方法，利用注意掩模来推进多对象语义分割。简而言之，我们将不同的语义对象嵌入不同的群集而不是传统的图像级嵌入。我们在与内部数据和Miccai挑战2015 BTCV数据集中的多器官医学图像分段任务中评估我们提出的方法。与目前的最先进的培训策略相比，我们拟议的管道分别产生了两种医学图像分割队列的骰子评分的大幅提高5.53％和6.09％（P值<0.01）。通过Pascal VOC 2012 DataSet进一步评估了所提出的方法的性能，并在MiOU（P值<0.01）上实现了2.75％的大幅提高。

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.

Purpose: The aim of this study was to demonstrate the utility of unsupervised domain adaptation (UDA) in automated knee osteoarthritis (OA) phenotype classification using a small dataset (n=50). Materials and Methods: For this retrospective study, we collected 3,166 three-dimensional (3D) double-echo steady-state magnetic resonance (MR) images from the Osteoarthritis Initiative dataset and 50 3D turbo/fast spin-echo MR images from our institute (in 2020 and 2021) as the source and target datasets, respectively. For each patient, the degree of knee OA was initially graded according to the MRI Osteoarthritis Knee Score (MOAKS) before being converted to binary OA phenotype labels. The proposed UDA pipeline included (a) pre-processing, which involved automatic segmentation and region-of-interest cropping; (b) source classifier training, which involved pre-training phenotype classifiers on the source dataset; (c) target encoder adaptation, which involved unsupervised adaption of the source encoder to the target encoder and (d) target classifier validation, which involved statistical analysis of the target classification performance evaluated by the area under the receiver operating characteristic curve (AUROC), sensitivity, specificity and accuracy. Additionally, a classifier was trained without UDA for comparison. Results: The target classifier trained with UDA achieved improved AUROC, sensitivity, specificity and accuracy for both knee OA phenotypes compared with the classifier trained without UDA. Conclusion: The proposed UDA approach improves the performance of automated knee OA phenotype classification for small target datasets by utilising a large, high-quality source dataset for training. The results successfully demonstrated the advantages of the UDA approach in classification on small datasets.

Image super-resolution is a common task on mobile and IoT devices, where one often needs to upscale and enhance low-resolution images and video frames. While numerous solutions have been proposed for this problem in the past, they are usually not compatible with low-power mobile NPUs having many computational and memory constraints. In this Mobile AI challenge, we address this problem and propose the participants to design an efficient quantized image super-resolution solution that can demonstrate a real-time performance on mobile NPUs. The participants were provided with the DIV2K dataset and trained INT8 models to do a high-quality 3X image upscaling. The runtime of all models was evaluated on the Synaptics VS680 Smart Home board with a dedicated edge NPU capable of accelerating quantized neural networks. All proposed solutions are fully compatible with the above NPU, demonstrating an up to 60 FPS rate when reconstructing Full HD resolution images. A detailed description of all models developed in the challenge is provided in this paper.

最近的成功表明，可以通过文本提示来操纵图像，例如，在雨天的晴天，在雨天中被操纵到同一场景中，这是由文本输入“下雨”驱动的雨天。这些方法经常利用基于样式的图像生成器，该生成器利用多模式（文本和图像）嵌入空间。但是，我们观察到，这种文本输入通常在提供和综合丰富的语义提示时被瓶颈瓶颈，例如将大雨与雨雨区分开。为了解决这个问题，我们主张利用另一种方式，声音，在图像操纵中具有显着优势，因为它可以传达出比文本更多样化的语义提示（生动的情感或自然世界的动态表达）。在本文中，我们提出了一种新颖的方法，该方法首先使用声音扩展了图像文本接头嵌入空间，并应用了一种直接的潜在优化方法来根据音频输入（例如雨的声音）操纵给定的图像。我们的广泛实验表明，我们的声音引导的图像操纵方法在语义和视觉上比最先进的文本和声音引导的图像操纵方法产生更合理的操作结果，这通过我们的人类评估进一步证实。我们的下游任务评估还表明，我们学到的图像文本单嵌入空间有效地编码声音输入。