Federated learning enables cooperative training among massively distributed clients by sharing their learned local model parameters. However, with increasing model size, deploying federated learning requires a large communication bandwidth, which limits its deployment in wireless networks. To address this bottleneck, we introduce a residual-based federated learning framework (ResFed), where residuals rather than model parameters are transmitted in communication networks for training. In particular, we integrate two pairs of shared predictors for the model prediction in both server-to-client and client-to-server communication. By employing a common prediction rule, both locally and globally updated models are always fully recoverable in clients and the server. We highlight that the residuals only indicate the quasi-update of a model in a single inter-round, and hence contain more dense information and have a lower entropy than the model, comparing to model weights and gradients. Based on this property, we further conduct lossy compression of the residuals by sparsification and quantization and encode them for efficient communication. The experimental evaluation shows that our ResFed needs remarkably less communication costs and achieves better accuracy by leveraging less sensitive residuals, compared to standard federated learning. For instance, to train a 4.08 MB CNN model on CIFAR-10 with 10 clients under non-independent and identically distributed (Non-IID) setting, our approach achieves a compression ratio over 700X in each communication round with minimum impact on the accuracy. To reach an accuracy of 70%, it saves around 99% of the total communication volume from 587.61 Mb to 6.79 Mb in up-streaming and to 4.61 Mb in down-streaming on average for all clients.

我们介绍了一个新颖的联合学习框架FedD3，该框架减少了整体沟通量，并开放了联合学习的概念，从而在网络受限的环境中进行了更多的应用程序场景。它通过利用本地数据集蒸馏而不是传统的学习方法（i）大大减少沟通量，并（ii）将转移限制为一击通信，而不是迭代的多路交流来实现这一目标。 FedD3允许连接的客户独立提炼本地数据集，然后汇总那些去中心化的蒸馏数据集（通常以几个无法识别的图像，通常小于模型小于模型），而不是像其他联合学习方法共享模型更新，而是允许连接的客户独立提炼本地数据集。在整个网络上仅一次形成最终模型。我们的实验结果表明，FedD3在所需的沟通量方面显着优于其他联合学习框架，同时，根据使用情况或目标数据集，它为能够在准确性和沟通成本之间的权衡平衡。例如，要在具有10个客户的非IID CIFAR-10数据集上训练Alexnet模型，FedD3可以通过相似的通信量增加准确性超过71％，或者节省98％的通信量，同时达到相同的准确性与其他联合学习方法相比。

车辆网络中的传感器数据共享可以显着提高连接自动化车辆环境感知的范围和准确性。已经开发了用于传播和融合传感器数据的不同概念和方案。对于这些方案而言，传感器的测量错误损害了感知质量，并可能导致道路交通事故。具体而言，当传感器的测量误差（也称为测量噪声）尚不清楚并且时间变化时，数据融合过程的性能受到限制，这代表了传感器校准的重大挑战。在本文中，我们考虑了具有车辆到基础设施和车辆到车辆通信的车辆网络中的传感器数据共享和融合。我们提出了一种名为双向反馈噪声估计（BIFNOE）的方法，其中边缘服务器从车辆收集和缓存传感器测量数据。边缘在双动态滑动时间窗口中交替估计噪声和目标，并以低通信成本来增强每辆车的分布式合作环境感测。我们通过模拟评估了应用程序方案中提出的算法和数据传播策略，并表明感知精度平均提高了80％左右，仅12 kbps上行链路和28 kbps的下行链路带宽。

深度学习是具有自动驾驶汽车和智能交通基础设施的合作智能运输系统（C-ITS）的环境感知功能的关键方法。在当今的C-IT中，智能流量参与者能够及时生成和传输大量数据。但是，由于隐私限制，这些数据不能直接用于模型培训。在本文中，我们介绍了一个联合学习框架应对等级异质性（H2-FED），该框架可以显着增强常规的预训练的深度学习模型。该框架利用车辆网络中连接的公共交通代理的数据，而不会影响用户数据隐私。通过协调包括路边单元和道路交通云在内的现有交通基础设施，该模型参数可有效地通过车辆通信和层次汇总进行分发。考虑到交通代理和路边单元之间数据分布，计算和通信功能的个人异质性，我们采用一种新方法来解决框架体系结构不同聚合层的异质性，即路边单元和云的集合。实验结果表明，根据当前通信网络中异质性的知识，我们的方法可以很好地平衡学习准确性和稳定性。与其他基线方法相比，联合数据集的评估表明，我们的框架更具通用性和功能，尤其是在沟通质量低的应用程序方案中。即使90％的代理人及时断开连接，预先训练的深度学习模型仍然可以稳定融合，并且收敛后其准确性可以从68％提高到90％以上。

Coronary Computed Tomography Angiography (CCTA) provides information on the presence, extent, and severity of obstructive coronary artery disease. Large-scale clinical studies analyzing CCTA-derived metrics typically require ground-truth validation in the form of high-fidelity 3D intravascular imaging. However, manual rigid alignment of intravascular images to corresponding CCTA images is both time consuming and user-dependent. Moreover, intravascular modalities suffer from several non-rigid motion-induced distortions arising from distortions in the imaging catheter path. To address these issues, we here present a semi-automatic segmentation-based framework for both rigid and non-rigid matching of intravascular images to CCTA images. We formulate the problem in terms of finding the optimal \emph{virtual catheter path} that samples the CCTA data to recapitulate the coronary artery morphology found in the intravascular image. We validate our co-registration framework on a cohort of $n=40$ patients using bifurcation landmarks as ground truth for longitudinal and rotational registration. Our results indicate that our non-rigid registration significantly outperforms other co-registration approaches for luminal bifurcation alignment in both longitudinal (mean mismatch: 3.3 frames) and rotational directions (mean mismatch: 28.6 degrees). By providing a differentiable framework for automatic multi-modal intravascular data fusion, our developed co-registration modules significantly reduces the manual effort required to conduct large-scale multi-modal clinical studies while also providing a solid foundation for the development of machine learning-based co-registration approaches.

The release of ChatGPT, a language model capable of generating text that appears human-like and authentic, has gained significant attention beyond the research community. We expect that the convincing performance of ChatGPT incentivizes users to apply it to a variety of downstream tasks, including prompting the model to simplify their own medical reports. To investigate this phenomenon, we conducted an exploratory case study. In a questionnaire, we asked 15 radiologists to assess the quality of radiology reports simplified by ChatGPT. Most radiologists agreed that the simplified reports were factually correct, complete, and not potentially harmful to the patient. Nevertheless, instances of incorrect statements, missed key medical findings, and potentially harmful passages were reported. While further studies are needed, the initial insights of this study indicate a great potential in using large language models like ChatGPT to improve patient-centered care in radiology and other medical domains.

Artificial Intelligence (AI) has become commonplace to solve routine everyday tasks. Because of the exponential growth in medical imaging data volume and complexity, the workload on radiologists is steadily increasing. We project that the gap between the number of imaging exams and the number of expert radiologist readers required to cover this increase will continue to expand, consequently introducing a demand for AI-based tools that improve the efficiency with which radiologists can comfortably interpret these exams. AI has been shown to improve efficiency in medical-image generation, processing, and interpretation, and a variety of such AI models have been developed across research labs worldwide. However, very few of these, if any, find their way into routine clinical use, a discrepancy that reflects the divide between AI research and successful AI translation. To address the barrier to clinical deployment, we have formed MONAI Consortium, an open-source community which is building standards for AI deployment in healthcare institutions, and developing tools and infrastructure to facilitate their implementation. This report represents several years of weekly discussions and hands-on problem solving experience by groups of industry experts and clinicians in the MONAI Consortium. We identify barriers between AI-model development in research labs and subsequent clinical deployment and propose solutions. Our report provides guidance on processes which take an imaging AI model from development to clinical implementation in a healthcare institution. We discuss various AI integration points in a clinical Radiology workflow. We also present a taxonomy of Radiology AI use-cases. Through this report, we intend to educate the stakeholders in healthcare and AI (AI researchers, radiologists, imaging informaticists, and regulators) about cross-disciplinary challenges and possible solutions.

The future of population-based breast cancer screening is likely personalized strategies based on clinically relevant risk models. Mammography-based risk models should remain robust to domain shifts caused by different populations and mammographic devices. Modern risk models do not ensure adaptation across vendor-domains and are often conflated to unintentionally rely on both precursors of cancer and systemic/global mammographic information associated with short- and long-term risk, respectively, which might limit performance. We developed a robust, cross-vendor model for long-term risk assessment. An augmentation-based domain adaption technique, based on flavorization of mammographic views, ensured generalization to an unseen vendor-domain. We trained on samples without diagnosed/potential malignant findings to learn systemic/global breast tissue features, called mammographic texture, indicative of future breast cancer. However, training so may cause erratic convergence. By excluding noise-inducing samples and designing a case-control dataset, a robust ensemble texture model was trained. This model was validated in two independent datasets. In 66,607 Danish women with flavorized Siemens views, the AUC was 0.71 and 0.65 for prediction of interval cancers within two years (ICs) and from two years after screening (LTCs), respectively. In a combination with established risk factors, the model's AUC increased to 0.68 for LTCs. In 25,706 Dutch women with Hologic-processed views, the AUCs were not different from the AUCs in Danish women with flavorized views. The results suggested that the model robustly estimated long-term risk while adapting to an unseen processed vendor-domain. The model identified 8.1% of Danish women accounting for 20.9% of ICs and 14.2% of LTCs.

Quaternion valued neural networks experienced rising popularity and interest from researchers in the last years, whereby the derivatives with respect to quaternions needed for optimization are calculated as the sum of the partial derivatives with respect to the real and imaginary parts. However, we can show that product- and chain-rule does not hold with this approach. We solve this by employing the GHRCalculus and derive quaternion backpropagation based on this. Furthermore, we experimentally prove the functionality of the derived quaternion backpropagation.

In this work, a method for obtaining pixel-wise error bounds in Bayesian regularization of inverse imaging problems is introduced. The proposed method employs estimates of the posterior variance together with techniques from conformal prediction in order to obtain coverage guarantees for the error bounds, without making any assumption on the underlying data distribution. It is generally applicable to Bayesian regularization approaches, independent, e.g., of the concrete choice of the prior. Furthermore, the coverage guarantees can also be obtained in case only approximate sampling from the posterior is possible. With this in particular, the proposed framework is able to incorporate any learned prior in a black-box manner. Guaranteed coverage without assumptions on the underlying distributions is only achievable since the magnitude of the error bounds is, in general, unknown in advance. Nevertheless, experiments with multiple regularization approaches presented in the paper confirm that in practice, the obtained error bounds are rather tight. For realizing the numerical experiments, also a novel primal-dual Langevin algorithm for sampling from non-smooth distributions is introduced in this work.