Self-supervised learning has proven to be an effective way to learn
representations in domains where annotated labels are scarce, such as medical
imaging. A widely adopted framework for this purpose is contrastive learning
and it has been applied to different scenarios. This paper seeks to advance our
understanding of the contrastive learning framework by exploring a novel
perspective: employing multi-organ datasets for pre-training models tailored to
specific organ-related target tasks. More specifically, our target task is
breast tumour segmentation in ultrasound images. The pre-training datasets
include ultrasound images from other organs, such as the lungs and heart, and
large datasets of natural images. Our results show that conventional
contrastive learning pre-training improves performance compared to supervised
baseline approaches. Furthermore, our pre-trained models achieve comparable
performance when fine-tuned with only half of the available labelled data. Our
findings also show the advantages of pre-training on diverse organ data for
improving performance in the downstream task.

利用自我监督学习和对比学习的方法，在医学成像等标注稀缺的领域中学习表征已被证明是一种有效的方式。本研究通过探索一种新的思路 —— 使用多器官数据集来为特定器官相关目标任务预训练模型，旨在推进我们对对比学习框架的理解。具体而言，我们的目标任务是超声图像中的乳腺肿瘤分割。预训练数据集包括来自其他器官（如肺和心脏）的超声图像以及大量的自然图像。我们的结果表明，与监督基线方法相比，传统的对比学习预训练可以提高性能。此外，我们的预训练模型在只使用一半可用标记数据进行微调时也可以达到相当的性能。我们的发现还表明，预训练多器官数据可以提高下游任务的性能。

多器官自监督对比学习用于乳腺病变分割

Multi-organ Self-supervised Contrastive Learning for Breast Lesion  Segmentation

Despite its benefits for tumour detection and treatment, the administration
of contrast agents in dynamic contrast-enhanced MRI (DCE-MRI) is associated
with a range of issues, including their invasiveness, bioaccumulation, and a
risk of nephrogenic systemic fibrosis. This study explores the feasibility of
producing synthetic contrast enhancements by translating pre-contrast
T1-weighted fat-saturated breast MRI to their corresponding first DCE-MRI
sequence leveraging the capabilities of a generative adversarial network (GAN).
Additionally, we introduce a Scaled Aggregate Measure (SAMe) designed for
quantitatively evaluating the quality of synthetic data in a principled manner
and serving as a basis for selecting the optimal generative model. We assess
the generated DCE-MRI data using quantitative image quality metrics and apply
them to the downstream task of 3D breast tumour segmentation. Our results
highlight the potential of post-contrast DCE-MRI synthesis in enhancing the
robustness of breast tumour segmentation models via data augmentation. Our code
is available at this https URL

利用生成对抗网络 (GAN) 将原始的 T1 加权饱和脂肪胸部 MRI 图像转化为相应的首次动态对比增强 MRI 序列，生成合成对比增强图像，并通过定量图像质量度量来评估生成的数据质量，将其应用于三维乳腺肿瘤分割，结果表明通过数据增强方式合成后的动态对比增强 MRI 图像在增强乳腺肿瘤分割模型的稳健性方面具有潜力，代码链接见摘要。