论文标题
对对比度学习医学图像细分的全球和本地特征的注释有限
Contrastive learning of global and local features for medical image segmentation with limited annotations
论文作者
论文摘要
监督深度学习成功的关键要求是一个大型标记的数据集 - 这种情况在医学图像分析中很难满足。自我监督的学习(SSL)可以通过提供未经标记数据的神经网络的策略来帮助这方面的帮助,然后对下游任务进行微调,并具有有限的注释。对比学习,是SSL的特定变体,是一种学习图像级表示的强大技术。在这项工作中,我们提出了通过利用特定于域特异性和特定问题的提示来扩展在半监督环境中分割体积医学图像的对比度学习框架的策略。具体而言,我们提出了(1)新型的对比策略,这些策略利用体积医学图像(域特异性提示)的结构相似性和(2)对比度损失的局部版本,以学习对每个像素段(问题特异性提示)有用的局部区域的独特表示。我们对三个磁共振成像(MRI)数据集进行了广泛的评估。在有限的注释环境中,与其他自学和半监督学习技术相比,提出的方法可以实现重大改进。当与简单的数据增强技术结合使用时,仅使用两个标记的MRI量进行训练,该方法仅在基准性能的8%以内,仅相当于用于训练基准测试的训练数据的4%(对于ACDC)。该代码在https://github.com/krishnabits001/domain_specific_cl上公开。
A key requirement for the success of supervised deep learning is a large labeled dataset - a condition that is difficult to meet in medical image analysis. Self-supervised learning (SSL) can help in this regard by providing a strategy to pre-train a neural network with unlabeled data, followed by fine-tuning for a downstream task with limited annotations. Contrastive learning, a particular variant of SSL, is a powerful technique for learning image-level representations. In this work, we propose strategies for extending the contrastive learning framework for segmentation of volumetric medical images in the semi-supervised setting with limited annotations, by leveraging domain-specific and problem-specific cues. Specifically, we propose (1) novel contrasting strategies that leverage structural similarity across volumetric medical images (domain-specific cue) and (2) a local version of the contrastive loss to learn distinctive representations of local regions that are useful for per-pixel segmentation (problem-specific cue). We carry out an extensive evaluation on three Magnetic Resonance Imaging (MRI) datasets. In the limited annotation setting, the proposed method yields substantial improvements compared to other self-supervision and semi-supervised learning techniques. When combined with a simple data augmentation technique, the proposed method reaches within 8% of benchmark performance using only two labeled MRI volumes for training, corresponding to only 4% (for ACDC) of the training data used to train the benchmark. The code is made public at https://github.com/krishnabits001/domain_specific_cl.