Elsevier

Medical Image Analysis

Volume 76, February 2022, 102328
Medical Image Analysis

CyCMIS: Cycle-consistent Cross-domain Medical Image Segmentation via diverse image augmentation

https://doi.org/10.1016/j.media.2021.102328Get rights and content

Highlights

  • Propose an end-to-end unsupervised cross-domain image segmentation framework integrating diverse image translation with semantic image segmentation into one network.

  • Propose the diverse inter-domain semantic consistency loss and the intra-domain semantic consistency loss to regularize the cross-modality segmentation process.

  • Extensive validation on two public datasets.

Abstract

Domain shift, a phenomenon when there exists distribution discrepancy between training dataset (source domain) and test dataset (target domain), is very common in practical applications and may cause significant performance degradation, which hinders the effective deployment of deep learning models to clinical settings. Adaptation algorithms to improve the model generalizability from source domain to target domain has significant practical value. In this paper, we investigate unsupervised domain adaptation (UDA) technique to train a cross-domain segmentation method which is robust to domain shift, and which does not require any annotations on the test domain. To this end, we propose Cycle-consistent Cross-domain Medical Image Segmentation, referred as CyCMIS, integrating online diverse image translation via disentangled representation learning and semantic consistency regularization into one network. Different from learning one-to-one mapping, our method characterizes the complex relationship between domains as many-to-many mapping. A novel diverse inter-domain semantic consistency loss is then proposed to regularize the cross-domain segmentation process. We additionally introduce an intra-domain semantic consistency loss to encourage the segmentation consistency between the original input and the image after cross-cycle reconstruction. We conduct comprehensive experiments on two publicly available datasets to evaluate the effectiveness of the proposed method. Results demonstrate the efficacy of the present approach.

Introduction

The past few years witnessed remarkable progress in medical image analysis due to the increasing availability of data and the rapid development of deep learning techniques (Litjens, Kooi, Bejnordi, Setio, Ciompi, Ghafoorian, Van Der Laak, Van Ginneken, Sánchez, 2017, Bernard, Lalande, Zotti, Cervenansky, Yang, Heng, Cetin, Lekadir, Camara, Ballester, et al., 2018, Zhuang, Li, Payer, Štern, Urschler, Heinrich, Oster, Wang, Smedby, Bian, et al., 2019, Wu, Tang, Li, Firmin, Yang, 2021). Deep learning-based methods, such as convolutional neural networks (CNNs), are excellent at learning from large amounts of data (Yang, Zhang, Firmin, Li, 2021, Yang, Ye, Xia, 2022), but can be poor at generalizing learned knowledge to new test datasets that differ from the training dataset (Choudhary, Tong, Zhu, Wang, 2020, Guan, Liu, 2021). Such distribution discrepancy between the training dataset (source domain) and the test dataset (target domain), referred as domain shift, occurs frequently in medical imaging due to factors such as changing imaging modalities (e.g. computed tomography (CT), magnetic resonance imaging (MRI), Ultrasound, etc.), protocols (e.g. MRI protocols like PDw, T1w, T2w, etc.), scanning parameters (e.g. MRI pulse sequence parameters like repetition time, echo time, inversion time, flip angle, etc.), subject cohorts, or machines from different vendors and clinical sites. Domain shift is very common in practical applications and may cause significant performance degradation, which hinders the effective deployment of deep learning models to clinical settings. For semantic segmentation, which is a prerequisite for many clinical applications including disease diagnosis, surgical planning and computer assisted interventions, manually annotating data with pixel-level annotations for each test domain is not a feasible solution. Adaptation algorithms to improve the model generalizability from source domain to target domain has significant practical value. In this work, we investigate unsupervised domain adaptation (UDA) technique to train a cross-domain segmentation method which is robust to domain shift, and which does not require any annotations on the test domain.

Given respectively two sets of unpaired data in two different domains, majority of existing unsupervised cross-domain segmentation methods are based on either feature alignment (Dou, Ouyang, Chen, Chen, Glocker, Zhuang, Heng, 2019, Wu, Zhuang, 2020) or image translation (Chartsias, Joyce, Dharmakumar, Tsaftaris, 2017, Chen, Ouyang, Tarroni, Schlemper, Qiu, Bai, Rueckert, 2019, Chen, Lian, Wang, Deng, Kuang, Fung, Gateno, Yap, Xia, Shen, 2020, Chen, Lian, Wang, Deng, Kuang, Fung, Gateno, Shen, Xia, Yap, 2021). Typically, image translation-based methods consist of two components: a cross-domain image synthesis component where adversarial learning with cycle-consistent reconstruction is leveraged to solve the problem of data without correspondence, and an image segmentation component. The identified limitations of existing methods include: (1) most of them do not preserve semantic information in the process of image translation such that any error generated in the cross-domain image synthesis stage will be passed to the image segmentation stage; and (2) the cross-domain image synthesis stage cannot benefit from the high-level semantic information obtained from the image segmentation stage.

In this paper, we propose Cycle-consistent Cross-domain Medical Image Segmentation, referred as CyCMIS, integrating diverse image translation via disentangled representation learning and semantic consistency regularization into one network. Instead of learning one-to-one mapping as in CycleGAN (Zhu et al., 2017), our method characterizes the complex relationship between domains as many-to-many mapping (Yang et al., 2019b), where images are embedded onto two spaces: a domain-invariant content space and a domain-specific attribute space. By enforcing diversity seeking regularization (Yang, Hong, Jang, Zhao, Lee, 2019, Mao, Lee, Tseng, Ma, Yang, 2019), disentangled content features can be combined with different attribute vectors to produce diverse images with identical content, which can be regarded as a way of online diverse image augmentation. Based on this, we further propose a novel diverse inter-domain semantic consistency loss to regularize the cross-domain segmentation. We additionally introduce an intra-domain semantic consistency loss to encourage the segmentation consistency between the original input and the image after cross-cycle reconstruction. Our contributions are summarized as follows:

  • 1.

    We propose an end-to-end unsupervised cross-domain image segmentation framework integrating diverse image translation with semantic image segmentation into one network such that the two parts can benefit from each other, i.e., better image translation will improve cross-domain image segmentation and conversely, better image segmentation will regularize cross-domain image translation.

  • 2.

    We introduce two consistency losses, i.e., the diverse inter-domain semantic consistency loss and the intra-domain semantic consistency loss, to further regularize the cross-domain segmentation process.

  • 3.

    We demonstrate on two public datasets that the proposed end-to-end network, which takes both content features and diverse appearance information into account, producing better segmentation than state-of-the-art (SOTA) cross-domain segmentation methods.

Section snippets

Related work

Unsupervised domain adaptation has been applied to a large number of medical image analysis tasks (Choudhary, Tong, Zhu, Wang, 2020, Guan, Liu, 2021). The existing methods can be largely categorized into two groups: shallow learning-based methods and deep learning-based methods. Below we will give a review of related work.

Method

Let xX and yY be images from two domains, and mxMX and myMY be corresponding labels to x and y, respectively. Note that x and y are not necessarily paired, and we have no access to MY in the training phase. Our goal is to design a network to segment unlabeled images in the target domain Y by making use of X and MX in the source domain. Fig. 1 shows an overview of the proposed CyCMIS framework which consists of two modules: a diverse image translation (DIT) module and a domain-specific

Experiments and results

In this section, we present the experimental results of the proposed CyCMIS framework. Two publicly available image datasets were used in our study: cardiac MR dataset from the Multi-Sequence Cardiac MR Segmentation (MS-CMRSeg) challenge (Zhuang, 2018) and CT-MR dataset from the Multi-Modality Whole Heart Segmentation (MM-WHS) challenge (Zhuang et al., 2019). The MS-CMRSeg challenge dataset contains 45 paired bSSFP CMR and LGE CMR images with ground truth annotations while the MM-WHS challenge

Discussions

Developing UDA methods for cross-domain medical image segmentation is challenging. The goal of the present study is to develop and validate an accurate method that can mitigate such a challenge. In this paper, we presented a cycle-consistent cross-domain medical image segmentation method called CyCMIS, integrating online diverse image translation via disentangled representation learning and semantic consistency regularization into one network. We conducted extensive validation studies to

Conclusion

In this paper, we proposed an end-to-end unsupervised cross-domain medical image segmentation method, taking advantage of diverse image translation via disentangled representation learning and consistency regularization into one network. We characterized the complex relationship between domains as many-to-many mapping and introduced a novel diverse inter-domain semantic consistency loss to regularize the cross-domain segmentation process. We additionally introduced an intra-domain semantic

CRediT authorship contribution statement

Runze Wang: Methodology, Software, Validation, Writing – original draft. Guoyan Zheng: Conceptualization, Methodology, Writing – original draft, Writing – review & editing, Supervision, Funding acquisition.

Declaration of Competing Interest

None.

Acknowledgments

This study was partially supported by Shanghai Municipal Science and Technology Commission via Project 20511105205 and by the Natural Science Foundation of China via project U20A20199.

References (44)

  • C. Chen et al.

    Unsupervised bidirectional cross-modality adaptation via deeply synergistic image and feature alignment for medical image segmentation

    IEEE Trans Med Imaging

    (2020)
  • C. Chen et al.

    Robust Multimodal Brain Tumor Segmentation via Feature Disentanglement and Gated Fusion

    In: International Conference on Medical Image Computing and Computer-Assisted Intervention

    (2019)
  • C. Chen et al.

    Unsupervised Multi-modal Style Transfer for Cardiac Mr Segmentation

    In: International Workshop on Statistical Atlases and Computational Models of the Heart

    (2019)
  • X. Chen et al.

    Anatomy-regularized representation learning for cross-modality medical image segmentation

    IEEE Trans Med Imaging

    (2020)
  • X. Chen et al.

    Diverse data augmentation for learning image segmentation with cross-modality annotations

    Med Image Anal

    (2021)
  • V. Cheplygina et al.

    Transfer learning for multicenter classification of chronic obstructive pulmonary disease

    IEEE J Biomed Health Inform

    (2017)
  • Q. Dou et al.

    Pnp-adanet: plug-and-play adversarial domain adaptation network at unpaired cross-modality cardiac segmentation

    IEEE Access

    (2019)
  • Y. Ganin et al.

    Domain-adversarial training of neural networks

    The journal of machine learning research

    (2016)
  • H. Guan et al.

    Domain adaptation for medical image analysis: a survey

    arXiv preprint arXiv:2102.09508

    (2021)
  • K. He et al.

    Deep Residual Learning for Image Recognition

    In: Proceedings of the IEEE conference on computer vision and pattern recognition pp. 770–778

    (2016)
  • T. Heimann et al.

    Learning without Labeling: Domain Adaptation for Ultrasound Transducer Localization

    In: International Conference on Medical Image Computing and Computer-Assisted Intervention

    (2013)
  • Y. Hiasa et al.

    Cross-modality Image Synthesis from Unpaired Data Using Cyclegan

    In: International workshop on simulation and synthesis in medical imaging

    (2018)
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