基于深度学习的医学影像分割研究综述

医学影像分割是计算机辅助诊断中的一项基础且关键的任务，目的在于从像素级别准确识别出目标器官、组织或病变区域。不同于自然场景下的图像，医学影像往往纹理复杂，同时受限于成像技术和成像设备，医学影像噪声大，边界模糊而不易判断。除此之外，对医学影像进行标注极大依赖于医疗专家的认知和经验，因此可用于训练中的标注数据少且存在标注误差。由于上述的医学影像边缘模糊不清、训练数据较少和标注误差较大等特点，基于传统图像分割算法搭建的辅助诊断系统难以满足临床应用的要求。近年来随着卷积神经网络（CNN）在计算机视觉和自然语言处理领域的广泛应用，基于深度学习的医学影像分割算法取得了极大的成功。首先概述了近几年基于深度学习的医学影像分割的研究进展，包括这些医学影像分割算法的基本结构、目标函数和优化方法。随后针对医学影像标注数据有限的问题，对目前半监督条件下医学影像分割的主流工作进行了整理归纳和分析。此外，还介绍了针对标注误差进行不确定度分析的相关工作。最后，总结分析了深度学习医学影像分割的特点并展望了未来的研究趋势。

Review of deep learning-based medical image segmentation

As a fundamental and key task in computer-aided diagnosis, medical image segmentation aims to accurately recognize the target regions such as organs, tissues and lesions at pixel level. Different from natural images, medical images show high complexity in texture and have the boundaries difficult to judge caused by ambiguity, which is the fault of much noise due to the limitations of the imaging technology and equipment. Furthermore, annotating medical images highly depends on expertise and experience of the experts, thereby leading to limited available annotations in the training and potential annotation errors. For medical images suffer from ambiguous boundary, limited annotated data and large errors in the annotations, which makes it is a great challenge for the auxiliary diagnosis systems based on traditional image segmentation algorithms to meet the demands of clinical applications. Recently, with the wide application of Convolutional Neural Network (CNN) in computer vision and natural language processing, deep learning-based medical segmentation algorithms have achieved tremendous success. Firstly the latest research progresses of deep learning-based medical image segmentation were summarized, including the basic architecture, loss function, and optimization method of the medical image segmentation algorithms. Then, for the limitation of medical image annotated data, the mainstream semi-supervised researches on medical image segmentation were summed up and analyzed. Besides, the studies related to measuring uncertainty of the annotation errors were introduced. Finally, the characteristics summary and analysis as well as the potential future trends of medical image segmentation were listed.