This paper explores the use of self-supervised deep learning in medical imaging in cases where two scan modalities are available for the same subject. Specifically, we use a large publicly-available dataset of over 20,000 subjects from the UK Biobank with both whole body Dixon technique magnetic resonance (MR) scans and also dual-energy x-ray absorptiometry (DXA) scans. We make three contributions: (i) We introduce a multi-modal image-matching contrastive framework, that is able to learn to match different-modality scans of the same subject with high accuracy. (ii) Without any adaption, we show that the correspondences learnt during this contrastive training step can be used to perform automatic cross-modal scan registration in a completely unsupervised manner. (iii) Finally, we use these registrations to transfer segmentation maps from the DXA scans to the MR scans where they are used to train a network to segment anatomical regions without requiring ground-truth MR examples. To aid further research, our code will be made publicly available.

本文探讨在医学成像中使用自监督深度学习的应用，特别是在存在两种扫描模式的同一主体的情况下。通过使用来自英国生物库的超过20,000个主体的完整身体迪克森技术磁共振（MR）扫描和双能X射线吸收计量（DXA）扫描的大型公开数据集，作者提出了一种针对多模式图像匹配对比框架，并且可以在没有监督的情况下执行自动跨模式扫描配准。最后,作者使用这些配准将DXA扫描的分割图传输到MR扫描中，在不需要地面真实MR样本的情况下，训练可以分割解剖区域的网络。

自我监督多模态全身医学影像对齐