Cited by 479Domain Adaptation and Few-Shot LearningArtificial Intelligence in Healthcare and EducationMedical Image Segmentation Techniques

Self-supervised learning for medical image classification: a systematic review and implementation guidelines

Open access
Huang, Shih-Cheng, Pareek, Anuj, Jensen, Malte, Lungren, Matthew P., Yeung, Serena, Chaudhari, Akshay S.·2023·npj Digital Medicine

Abstract

Advancements in deep learning and computer vision provide promising solutions for medical image analysis, potentially improving healthcare and patient outcomes. However, the prevailing paradigm of training deep learning models requires large quantities of labeled training data, which is both time-consuming and cost-prohibitive to curate for medical images. Self-supervised learning has the potential to make significant contributions to the development of robust medical imaging models through its ability to learn useful insights from copious medical datasets without labels. In this review, we provide consistent descriptions of different self-supervised learning strategies and compose a systematic review of papers published between 2012 and 2022 on PubMed, Scopus, and ArXiv that applied self-supervised learning to medical imaging classification. We screened a total of 412 relevant studies and included 79 papers for data extraction and analysis. With this comprehensive effort, we synthesize the collective knowledge of prior work and provide implementation guidelines for future researchers interested in applying self-supervised learning to their development of medical imaging classification models.

AI snapshot

Written from the paper’s full text.

TL;DR

This systematic review synthesizes 79 studies applying self-supervised learning (SSL) to medical image classification and finds that SSL pre-training generally improves downstream performance over purely supervised or non-SSL baselines. It also provides terminology, implementation guidelines, and highlights that optimal SSL strategies remain uncertain due to heterogeneous studies and limited direct comparisons.

Key findings

  • From 412 identified studies, 148 full-text screened, and 79 included; most SSL models improved performance, with relative increases of 0.216–32.6% AUROC, 0.440–29.2% accuracy, and 0.137–14.3% F1 over the same architecture without SSL pre-training, while five studies reported slight decreases of 0.980–4.51%.
  • Contrastive learning was the most common strategy (44/79), with SimCLR, MoCo, and BYOL used in 13, 8, and 3 papers, respectively; 36 studies comparing contrastive SSL to supervised pre-training reported an average improvement of 6.35%.
  • Innate relationship SSL was used in 15/79 studies; clinically relevant pre-text tasks achieved greater average improvement over supervised methods than transformation-based tasks (13.7% vs. 5.03%). Generative SSL appeared in 3/79, self-prediction in 6/79, and combined strategies in 11/79; all 8 combined-strategy studies that compared with purely supervised approaches reported improvement (0.140–8.29%).
  • End-to-end fine-tuning tended to outperform training a classifier on extracted features; of 11 studies with quantitative comparisons, 8 favored end-to-end fine-tuning. Radiology was the most represented clinical domain (47/79), followed by pathology (12/79).

Methods

  • PRISMA-based systematic review searching PubMed, Scopus, and ArXiv for papers published between January 2012 and May 2021, using search terms combining “self-supervised learning” and “medical imaging.”
  • Inclusion required English, peer-reviewed original research applying SSL to a downstream clinical medical image classification task; exclusions included semi-supervised learning, any manual labels during self-supervision, regression- or segmentation-only downstream tasks, and non-human medical imaging.
  • Screening used Covidence by three independent researchers, with disagreements resolved by discussion and a fourth arbitrator if needed. Data extraction recorded SSL strategy, modality, clinical domain, task, framework, fine-tuning strategy, metrics, SSL and supervised performance, and relative differences; AUROC was prioritized, then accuracy, F1, and sensitivity.

Limitations

  • Stated by the paper: publication bias may overestimate SSL benefits; the post-2012 search excluded pre-deep-learning SSL work; studies could not be aggregated or statistically compared because of different modalities, metrics, and objectives; categorizing SSL strategies introduced subjectivity; and the review was limited to classification, excluding segmentation, regression, and registration.
  • Evident from the text: only 33/79 studies compared with another SSL strategy, only 18/79 used natural-image pre-trained weights, and only 13 compared feature extraction with end-to-end fine-tuning (two without numerical results), indicating limited baselines and ablation experiments.

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Registry

Crossref · 10.1038/s41746-023-00811-0

Cites

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Statistics

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Claims the paper makes

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  • Findingown data

    79 studies were included for systematic review and data extraction.

    “We screened a total of 412 relevant studies and included 79 papers for data extraction and analysis.”
    • Also stated in: § Results · plain
      “A total of 79 studies fulfilled our eligibility criteria and were included for systematic review and data extraction.”
    • Also stated in: § Results · plain
      “Out of 412 studies identified from PubMed, Scopus, and ArXiv, 79 studies were included in the systematic review.”
    Quote in the paperSubstantial claim
  • Findingcitation

    Nine of the innate relationship studies designed their pre-text task based on different image transformations, including rotation prediction, horizontal flip prediction, reordering shuffled slices, and patch order prediction.

    “Nine of these studies designed their innate relationship pre-text task based on different image transformations, including rotation prediction44–47, horizontal flip prediction48, reordering shuffled slices49, and patch order prediction46,50–52.”
    Quote in the paperNot a substantial claim0 of 6 sources checked
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  • Findingown data

    The remaining six innate relationship studies designed clinically relevant pre-text tasks by exploiting the unique properties of medical images.

    “The remaining six studies designed clinically relevant pre-text tasks by exploiting the unique properties of medical images.”
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  • Findingown data

    Innate relationship was used in 15 out of 79 included studies.

    “Innate relationship was used in 15 out of 79 studies (Table 1).”
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  • Findingown data

    The systematic search identified 412 unique studies.

    “We screened a total of 412 relevant studies and included 79 papers for data extraction and analysis.”
    • Also stated in: § Results · plain
      “A total of 412 unique studies were identified through our systematic search.”
    • Also stated in: § Results · plain
      “Out of 412 studies identified from PubMed, Scopus, and ArXiv, 79 studies were included in the systematic review.”
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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    There is already a growing trend in recent medical imaging AI literature to leverage SSL.

    “While there is already a growing trend in recent medical imaging AI literature to leverage SSL (Fig. 1)”
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    Findingcitation

    Of the three generative SSL studies, two reported comparisons with purely supervised models and showed relative improvements of 16.6% and 24.5% with self-supervised learning.

    “Of the three studies, two reported comparisons with purely supervised models and showed relative improvements of 16.6%58 and 24.5%56 with self-supervised learning.”
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    • cites [58] Zhao, Q., Liu, Z., Adeli, E. & Pohl, K. M. Longitudinal Self-Supervised Learning. Med. Image Anal. 71, (2021). source

      Not checked in the free run.

    • cites [56] Gamper, J. & Rajpoot, N. Multiple Instance Captioning: Learning Representations from Histopathology Textbooks and Articles. In 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 16544–16554 (2021). source

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    Findingown data

    Out of all innate relationship based studies, ten compared performance to supervised pre-trained models and eight of them showed improvement.

    “Out of all innate relationship based studies, ten compared performance to those of supervised pre-trained models and eight of them showed improvement in performance.”
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    Findingcitation

    The pathology tasks were focused on histopathological classification, with the majority focused on colorectal cancer classification.

    “The tasks were focused on histopathological classification, where the majority focused on colorectal cancer classification68,84–87.”
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    • cites [68] Ke, J., Shen, Y., Liang, X. & Shen, D. Contrastive Learning Based Stain Normalization Across Multiple Tumor in Histopathology. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2021 571–580 (Springer International Publishing, 2021). source

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    • cites [84] Yang, P., Hong, Z., Yin, X., Zhu, C. & Jiang, R. Self-supervised Visual Representation Learning for Histopathological Images. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2021 47–57 (Springer International Publishing, 2021). source

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    • cites [85] Ciga, O., Xu, T. & Martel, A. L. Self supervised contrastive learning for digital histopathology. Machine Learning with Applications 7, (2022). source

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    • cites [86] Li, J., Lin, T. & Xu, Y. SSLP: Spatial Guided Self-supervised Learning on Pathological Images. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2021 3–12 (2021). source

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    • cites [87] Srinidhi, C. L., Kim, S. W., Chen, F.-D. & Martel, A. L. Self-supervised driven consistency training for annotation efficient histopathology image analysis. Med. Image Anal. 75, (2021). source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Combined strategies are typically the proposed method in the manuscripts.

    “However, it is important to note that combined strategies are typically the proposed method in the manuscripts, and thus publication bias might have resulted in this trend.”
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    Findingown data

    Thirty-six studies compared contrastive SSL pre-training to supervised pre-training and reported an average improvement in performance of 6.35%.

    “Thirty-six studies compared contrastive SSL pre-training to supervised pre-training and reported an average improvement in performance of 6.35%.”
    Quote in the paperSubstantial claim
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    Findingnone given

    The pathology field is centered around medical imaging in the form of whole slide images.

    “Similar to radiology, this field is centered around medical imaging in the form of whole slide images.”
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    Findingown data

    Among the SSL baselines, SimCLR was most frequently compared (16/26), followed by autoencoders (11/26) and MoCo (9/26).

    “Among the SSL baselines, SimCLR was most frequently compared (16/26), followed by autoencoders (11/26) and MoCo (9/26).”
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    Findingcitation

    Two of the five self-prediction studies compared their approach to models without self-supervised pre-training and reported slight relative improvements in performance of 1.12% and 0.690%.

    “Two of the five studies compared their approach to models without self-supervised pre-training and reported slight relative improvements in performance of 1.12%67 and 0.690%63.”
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    • cites [67] Park, J., Kwak, I.-Y. & Lim, C. A Deep Learning Model with Self-Supervised Learning and Attention Mechanism for COVID-19 Diagnosis Using Chest X-ray Images. Electronics 10, 1996 (2021). source

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    • cites [63] Liu, C. et al. TN-USMA Net: Triple normalization-based gastrointestinal stromal tumors classification on multicenter EUS images with ultrasound-specific pre-training and meta attention. Med. Phys. 48, 7199–7214 (2021). source

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    Findingown data

    Self-supervised learning strategies generate label-efficient representations, but the learning process typically requires a relatively large amount of unlabeled data.

    “Furthermore, even though self-supervised learning strategies generate label-efficient representations, the learning process typically requires a relatively large amount of unlabeled data.”
    Quote in the paperNot a substantial claim
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    Findingcitation

    The remaining studies explored multiple other tasks and many focused on classification of malignant disorders such as breast cancer, skin cancer, and lung cancer.

    “The remaining studies explored multiple other tasks and many focused on classification of malignant disorders such as breast cancer56,61,88, skin cancer89, and lung cancer59.”
    Quote in the paperNot a substantial claim0 of 5 sources checked
    • cites [56] Gamper, J. & Rajpoot, N. Multiple Instance Captioning: Learning Representations from Histopathology Textbooks and Articles. In 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 16544–16554 (2021). source

      Not checked in the free run.

    • cites [61] Wang, X. et al. TransPath: Transformer-Based Self-supervised Learning for Histopathological Image Classification. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2021 186–195 (2021). source

      Not checked in the free run.

    • cites [88] Dehaene, O., Camara, A., Moindrot, O., de Lavergne, A. & Courtiol, P. Self-Supervision Closes the Gap Between Weak and Strong Supervision in Histology. in ML4H 2020 NeurIPS workshop (2020).

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    • cites [89] Liu, Q. et al. SimTriplet: Simple Triplet Representation Learning with a Single GPU. In Medical Image Computing and Computer Assisted Intervention–MICCAI 2021. Part II 24, 102–112 (2021). source

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    • cites [59] Li, B., Li, Y. & Eliceiri, K. W. Dual-stream Multiple Instance Learning Network for Whole Slide Image Classification with Self-supervised Contrastive Learning. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition. (2021). source

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    Findingcitation

    A particularly interesting medical task explored was classification of psychiatric diseases or psychiatric traits using fMRI.

    “A particularly interesting medical task that was explored was classification of psychiatric diseases or psychiatric traits using fMRI57,62,90.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [57] Osin, J. et al. Learning Personal Representations from fMRI by Predicting Neurofeedback Performance. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2020 469–478 (2020). source

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    • cites [62] Dufumier, B. et al. Contrastive Learning with Continuous Proxy Meta-data for 3D MRI Classification. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2021 58–68 (2021). source

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    • cites [90] Hashimoto, Y., Ogata, Y., Honda, M. & Yamashita, Y. Deep Feature Extraction for Resting-State Functional MRI by Self-Supervised Learning and Application to Schizophrenia Diagnosis. Front. Neurosci. 15, 696853 (2021). source

      Not checked in the free run.

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    Findingown data

    Eight of the studies that combined different strategies compared self-supervised pre-training with purely supervised approaches, all of which reported performance improvement (0.140-8.29%).

    “Eight of the studies that combined different strategies compared self-supervised pre-training with purely supervised approaches, all of which reported performance improvement (0.140–8.29%).”
    Quote in the paperSubstantial claim
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    Findingown data

    SimCLR, MoCo and BYOL were the three most used contrastive frameworks, applied in 13, 8, and 3 papers, respectively.

    “SimCLR, MoCo and BYOL were the three most used frameworks, applied in 13, 8, and 3 papers, respectively.”
    Quote in the paperNot a substantial claim
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    Findingnone given

    Masking and cropping operations can obscure the cavernoma and alter the semantic meaning of the image, as the MRI-scan no longer exhibits any abnormality.

    “b and c Masking and cropping operations can obscure the cavernoma and alter the semantic meaning of the image, as the MRI-scan no longer exhibits any abnormality.”
    Quote in the paperSubstantial claim
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    Findingown data

    The included studies use different imaging modalities, report different performance metrics, and investigate different objectives.

    “Furthermore, we are unable to aggregate or statistically compare the effects of each self-supervised learning strategy on performance gain, since the included studies use different imaging modalities, report different performance metrics, and investigate different objectives.”
    Quote in the paperSubstantial claim
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    Findingnone given

    Masking and cropping operations do not obscure the dog nor alter the semantic meaning of the image.

    “d Image of a dog (bounded in red), (e) and (f) Masking and cropping operations do not obscure the dog nor alter the semantic meaning of the image.”
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    Premisecitation

    With such an immense cognitive burden placed on radiologists, delays in diagnosis and diagnostic errors are unavoidable.

    “With such an immense cognitive burden placed on radiologists, delays in diagnosis and diagnostic errors are unavoidable6,7.”
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    • cites [6] Alonso-Martínez, J. L., Sánchez, F. J. A. & Echezarreta, M. A. U. Delay and misdiagnosis in sub-massive and non-massive acute pulmonary embolism. Eur. J. Intern. Med. 21, 278–282 (2010). source

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    • cites [7] Hendriksen, J. M. T. et al. Clinical characteristics associated with diagnostic delay of pulmonary embolism in primary care: a retrospective observational study. BMJ Open 7, e012789 (2017). source

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    Premisecitation

    Pre-trained large language models are capable of achieving state-of-the-art results for a wide range of NLP tasks, and have shown the ability to perform well on new tasks with only a fraction of the labeled data that traditional supervised learning techniques require.

    “These pre-trained large language models18,19 are capable of achieving state-of-the-art results for a wide range of NLP tasks, and have shown the ability to perform well on new tasks with only a fraction of the labeled data that traditional supervised learning techniques require.”
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    • cites [18] Devlin, J., Chang, M.-W., Lee, K. & Toutanova, K. BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding. Preprint at https://arxiv.org/abs/1810.04805 (2018).

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    • cites [19] Brown, T., Mann, B. & Ryder, N. Language models are few-shot learners. Adv. Neural Inf. Process. Syst. (2020).

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  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationreasoning

    Reducing the number of manual annotations required to train medical imaging models will significantly reduce both the cost and time required for model development, making automated systems more accessible to different specialties and hospitals, thereby reducing workload for radiologists and potentially improving patient care.

    “Reducing the number of manual annotations required to train medical imaging models will significantly reduce both the cost and time required for model development, making automated systems more accessible to different specialties and hospitals, thereby reducing workload for radiologists and potentially improving patient care.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Annotating medical imaging datasets requires domain expertize, making large-scale annotations cost-prohibitive and time-consuming.
    • Rests on an assumption: The current success of deep learning has been largely dominated by supervised learning frameworks, which typically require large-scale labeled datasets to achieve high performance.
    • Rests on an assumption: The inability to generalize can be largely due to the process of supervised learning, which encourages the model to mainly learn features heavily correlated with specific labels rather than general features representative of the whole data distribution.
    • Rests on an assumption: In a healthcare system where a myriad of opportunities and possibilities for automation exist, it is practically impossible to curate labeled datasets for all tasks, modalities, and outcomes for training supervised models.
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    Study design and conductnone given

    The authors independently screened all records for eligibility.

    “The authors independently screened all records for eligibility.”
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    Premisecitation

    Augmentations and transformations alter the semantic meaning of medical images but not natural images.

    “Examples of augmentations and transformations that alter the semantic meaning of medical images144 but not natural images145.”
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    • cites [144] Hellerhoff. File:Kavernom rechts parietal 59M - MR - 001.jpg. Wikimedia https://commons.wikimedia.org/wiki/File:Kavernom_rechts_parietal_59M_-_MR_-_001.jpg (2022).

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    • cites [145] Matio, H. File:Dog Breeds.jpg. Wikimedia Commons https://commons.wikimedia.org/wiki/File:Dog_Breeds.jpg (2019).

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    Premisecitation

    Yan et al. have demonstrated the possibility of training self-supervised models with data from multiple healthcare centers without explicitly sharing data, and have shown improvement in robustness and performance over models trained using data from only one institution.

    “Nevertheless, using federated learning, Yan et al. have demonstrated the possibility of training self-supervised models with data from multiple healthcare centers without the need for explicitly sharing data, and have shown improvement in robustness and performance over models trained using data from only one institution97.”
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    • cites [97] Yan, R. et al. Label-Efficient Self-Supervised Federated Learning for Tackling Data Heterogeneity in Medical Imaging. IEEE Transactions on Medical Imaging (2023). source

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    • Rests on an assumption: Curating large-scale medical image datasets from multiple institutions is often challenged by the difficulty of sharing patient data while preserving patient privacy.
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    Premisecitation

    For natural image datasets, MoCo outperforms MAE by training a linear model on extracted features (linear probing), while MAE achieves better performance than MoCo as the number of fine-tune layers increases.

    “For instance, for natural image datasets, MoCo outperforms MAE by training a linear model on extracted features (linear probing), while MAE achieves better performance than MoCo as the number of fine-tune layers increases41.”
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    • cites [41] He, K. et al. Masked Autoencoders Are Scalable Vision Learners. Proc. IEEE/CVF Conf. Comput. Vis. Pattern Recognit. (CVPR) 2022, 16000–16009 (2022).

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    Interpretationcitation

    Representations learned using certain SSL strategies can be relatively more linearly separable, while representations from other strategies can achieve better performance when more layers or the entire model are fine-tuned.

    “It is worth noting that representations learned using certain SSL strategies can be relatively more linearly separable, while representations from other strategies can achieve better performance when more layers or the entire model are fine-tuned.”
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    Interpretationnone given

    The random masking operation often utilized by self-prediction self-supervised learning methods may also alter a medical image's semantic meaning by removing image regions with diseases or abnormalities.

    “The random masking operation often utilized by self-prediction self-supervised learning methods may also alter a medical image’s semantic meaning by removing image regions with diseases or abnormalities (Fig. 5b).”
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    Interpretationnone given

    Factors such as the degree of domain shift between SSL pre-training data and downstream task data could also affect the linear separability of the representations.

    “Factors such as the degree of domain shift between SSL pre-training data and downstream task data could also affect the linear separability of the representations.”
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    Premisereasoning

    These contrastive methods typically apply strong transformations to the original image and encourage the model to learn similar global representations for images with similar semantic meanings.

    “Therefore, these methods typically apply strong transformations to the original image and encourage the model to learn similar global representations for images with similar semantic meanings.”
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    Interpretationreasoning

    The unique attributes of medical images can also be utilized for creating relevant pre-text tasks.

    “The unique attributes of medical images can also be utilized for creating relevant pre-text tasks.”
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    Study design and conductnone given

    In cases where consensus could not be achieved, a fourth arbitrating researcher was consulted.

    “In cases where consensus could not be achieved a fourth arbitrating researcher was consulted (A.S.C.).”
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    Study design and conductcitation

    The search was limited to papers published after 2012, which excluded papers that applied self-supervised learning prior to the era of deep learning for computer vision.

    “We also limited our search to only consider papers published after 2012, which excluded papers that applied self-supervised learning prior to the era of deep learning for computer vision108.”
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    • cites [108] Russakovsky, O. et al. ImageNet Large Scale Visual Recognition Challenge. Int. J. Comput. Vis. 115, 211–252 (2015). source

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    Premisecitation

    Rivail et al. proposed a self-supervised approach to model disease progression by estimating the time interval between pairs of optical coherence tomography (OCT) scans from the same patient.

    “Rivail et al. proposed a self-supervised approach to model disease progression by estimating the time interval between pairs of optical coherence tomography (OCT) scans from the same patient104.”
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    • cites [104] Rivail, A. et al. Modeling Disease Progression in Retinal OCTs with Longitudinal Self-supervised Learning. in Predictive Intelligence in Medicine 44–52 (2019). source

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    Interpretationnone given

    Publication bias can be a considerable limitation due to disproportionately reported positive results in the literature, which can lead to overestimation of the benefits of self-supervised learning.

    “For this review paper, publication bias can be a considerable limitation due to disproportionately reported positive results in the literature, which can lead to overestimation of the benefits of self-supervised learning.”
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    Interpretationnone given

    Self-supervised pre-trained models can also be fine-tuned for other important medical tasks, including segmentation, regression, and registration.

    “Lastly, our study selection criteria only included literature for the task of medical image classification, which limits the scope of this review paper, since we recognize that self-supervised pre-trained models can also be fine-tuned for other important medical tasks, including segmentation, regression, and registration.”
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    Study design and conductcitation

    This systematic review was conducted based on the PRISMA guidelines.

    “This systematic review was conducted based on the PRISMA guidelines109.”
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    • cites [109] Page, M. J. et al. “The PRISMA 2020 statement: an updated guideline for reporting systematic reviews.” International journal of surgery. 88 (2021).

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    Study design and conductown data

    Study selection was performed by three independent researchers, and disagreements were resolved through discussion.

    “Study selection was performed by three independent researchers (S.-C.H., A.P., and M.J.), and disagreements were resolved through discussion.”
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    Premisecitation

    Jiao et al. leveraged the correlation between fetal ultrasonography and the narrative speech of the sonographer to create a pre-text task for self-supervision, and subsequently used the learned representations for downstream standard plane classification on sonograms.

    “Jiao et al. cleverly leveraged the correlation between fetal ultrasonography and the narrative speech of the sonographer to create a pre-text task for self-supervision, and subsequently used the learned representations for downstream standard plane classification on sonograms53.”
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    • cites [53] Jiao, J. et al. Self-Supervised Contrastive Video-Speech Representation Learning for Ultrasound. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2020 534–543 (2020). source

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    Taleb et al. proposed a multimodal contrastive learning strategy between retinal fundus images and genetics data and showed improvement in performance over single modality pre-training.

    “For example, Taleb et al. proposed a multimodal contrastive learning strategy between retinal fundus images and genetics data and showed improvement in performance over single modality pre-training105.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [105] Taleb A., Kirchler M. & Monti R. ContIG: Self-supervised Multimodal Contrastive Learning for Medical Imaging with Genetics. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition. 20908–20921 (2022). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Subjectivity may have been introduced when categorizing the self-supervised learning strategy in each paper, especially for studies that implemented novel, unconventional, or a mixture of methods.

    “In addition, subjectivity may have been introduced when categorizing the self-supervised learning strategy in each paper, especially for studies that implemented novel, unconventional, or a mixture of methods.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The search encompassed papers published between January 2012 and May 2021.

    “The search encompassed papers published between January 2012 and May 2021.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisecitation

    Several studies have utilized medical reports to provide supervision signals during self-supervised learning and shown label efficiency for downstream tasks.

    “Several studies have utilized these medical reports to provide supervision signals during self-supervised learning and shown label efficiency for downstream tasks60,106.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [60] Ji, Z. et al. Improving Joint Learning of Chest X-Ray and Radiology Report by Word Region Alignment. In Machine Learning in Medical Imaging 110–119 (2021). source

      Not checked in the free run.

    • cites [106] Zhang, Y., Jiang, H., Miura, Y., Manning, C. D. & Langlotz, C. P. Contrastive Learning of Medical Visual Representations from Paired Images and Text. Preprint at https://arxiv.org/abs/2010.00747 (2020).

      Not checked in the free run.

    • Rests on an assumption: Many medical imaging modalities have corresponding radiology reports that contain detailed descriptions of the medical conditions observed by radiologists.
  • May combine two claims.

    Premisecitation

    Huang et al. demonstrated the model's ability to localize chest abnormalities on chest x-rays without segmentation labels and revealed the possibility of zero-shot learning by converting the classification classes into textual captions and framing the image classification task as measuring image-text similarity.

    “By leveraging radiology reports, Huang et al. demonstrated the model’s ability to localize chest abnormalities on chest x-rays without segmentation labels and revealed the possibility of zero-shot learning by converting the classification classes into textual captions and framing the image classification task as measuring the image-text similarity107.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [107] Huang, S.-C., Shen, L., Lungren, M. P. & Yeung, S. GLoRIA: A multimodal global-local representation learning framework for label-efficient medical image recognition. In 2021 IEEE/CVF International Conference on Computer Vision (ICCV) (2021). source

      Not checked in the free run.

    • Rests on an assumption: Many medical imaging modalities have corresponding radiology reports that contain detailed descriptions of the medical conditions observed by radiologists.
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    A systematic literature search was implemented in three literature databases: PubMed, Scopus and ArXiv.

    “A systematic literature search was implemented in three literature databases: PubMed, Scopus and ArXiv.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

    Interpretationnone given

    The flexibility in creating self-supervised methods as well as the adaptability and transferability to multiple medical domains highlights the importance and utility of self-supervised techniques in clinical applications.

    “Overall, the flexibility in creating self-supervised methods as well as the adaptability and transferability to multiple medical domains highlights the importance and utility of self-supervised techniques in clinical applications.”
    Quote in the paperNot a substantial claim
44 of 44
  • The paper relies on this without support.

    Annotating medical imaging datasets requires domain expertize, making large-scale annotations cost-prohibitive and time-consuming.

    “However, the prevailing paradigm of training deep learning models requires large quantities of labeled training data, which is both time-consuming and cost-prohibitive to curate for medical images.”
    “However, annotating medical imaging datasets requires domain expertize, making large-scale annotations cost-prohibitive and time-consuming, which fundamentally limits building effective medical imaging models across varying clinical use cases.”
  • The paper relies on this without support.

    The current success of deep learning has been largely dominated by supervised learning frameworks, which typically require large-scale labeled datasets to achieve high performance.

    “While deep learning provides promising solutions for improving medical image interpretation, the current success has been largely dominated by supervised learning frameworks, which typically require large-scale labeled datasets to achieve high performance.”
  • The paper relies on this without support.

    The inability to generalize can be largely due to the process of supervised learning, which encourages the model to mainly learn features heavily correlated with specific labels rather than general features representative of the whole data distribution.

    “The inability to generalize can be largely due to the process of supervised learning, which encourages the model to mainly learn features heavily correlated with specific labels rather than general features representative of the whole data distribution.”
  • The paper relies on this without support.

    In a healthcare system where a myriad of opportunities and possibilities for automation exist, it is practically impossible to curate labeled datasets for all tasks, modalities, and outcomes for training supervised models.

    “In a healthcare system where a myriad of opportunities and possibilities for automation exist, it is practically impossible to curate labeled datasets for all tasks, modalities, and outcomes for training supervised models.”
  • The paper relies on this without support.

    SSL can create generalist models that can be fine-tuned for many downstream tasks without large-scale labeled datasets.

    “Unlike supervised learning, SSL can create generalist models that can be fine-tuned for many downstream tasks without large-scale labeled datasets.”
  • The paper relies on this without support.

    The most suitable strategies and best practices for medical images have not been sufficiently investigated.

    “the most suitable strategies and best practices for medical images have not been sufficiently investigated.”
  • The paper relies on this without support.

    Many clinical tasks are based on classification.

    “We focus on medical image classification tasks because many clinical tasks are based on classification, and thus our research may be directly applicable to deep learning models for clinical workflows.”
  • The paper relies on this without support.

    SSL is task agnostic, and the same SSL pre-trained model can be fine-tuned for different types of downstream tasks, including classification, segmentation, and object detection.

    “It is worth emphasizing that SSL is task agnostic, and the same SSL pre-trained model can be fine-tuned for different types of downstream tasks, including classification, segmentation, and object detection.”
  • The paper relies on this without support.

    Current limited knowledge and understanding of possible imaging features arising in psychiatric diseases constitutes a major clinical challenge to making local annotations such as bounding boxes or segmentations on brain scans.

    “Current limited knowledge and understanding of possible imaging features arising in psychiatric diseases constitutes a major clinical challenge to making local annotations such as bounding boxes or segmentations on brain scans.”
  • The paper relies on this without support.

    Curating large-scale medical image datasets from multiple institutions is often challenged by the difficulty of sharing patient data while preserving patient privacy.

    “Curating large-scale medical image datasets from multiple institutions is often challenged by the difficulty of sharing patient data while preserving patient privacy.”
  • The paper relies on this without support.

    Many medical imaging modalities have corresponding radiology reports that contain detailed descriptions of the medical conditions observed by radiologists.

    “Furthermore, many medical imaging modalities have corresponding radiology reports that contain detailed descriptions of the medical conditions observed by radiologists.”
  • The paper relies on this without support.

    Currently there are very few publicly available medical image datasets with corresponding radiology reports, largely due to the difficulties in preserving patient privacy.

    “However, currently there are very few publicly available medical image datasets with corresponding radiology reports, largely due to the difficulties in preserving patient privacy.”
  • The paper relies on this without support.

    Many models pre-trained in a self-supervised manner on large-scale natural image datasets are publicly available.

    “Although self-supervised pre-training can be computationally demanding, many models pre-trained in a self-supervised manner on large-scale natural image datasets are publicly available and should be utilized.”
13 of 13

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The expanding literature on SSL in medical imaging focuses primarily on 2D images for diagnostic applications.

    “The expanding literature on SSL in medical imaging13 focuses primarily on two-dimensional (2D) images (X-ray, whole slide images, dermatology images, fundus images and so on) for diagnostic applications.”

    From Foundation Model for Cancer Imaging Biomarkers (2024) · cites this paper as [13]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Search end date conflicts with the stated review period

    Major

    The abstract says the review covered papers through 2022, but Methods says the search ended in May 2021. Table 1 also includes a study dated 2022, so the stated search window cannot account for all included studies.

  • Fine-tuning results are attributed to the wrong figure panel

    Minor

    The implementation guidelines cite Fig. 4c for the finding about end-to-end fine-tuning. The figure caption assigns fine-tuning comparisons to panel d; panel c compares SSL strategies.

  • Self-prediction comparison count omits a study

    Minor

    The self-prediction section describes comparisons by two of five studies, although it earlier says six studies were included. Table 1 reports supervised and SSL performance for Tamkin as well as the Park and Liu comparisons cited in that section, making at least three comparisons.

3 of 3

Cites

Flagged first, then by citations

6 of the 130 references couldn’t be matched to a known paper.

Research works printed but not linked: 21

  1. Brown, T., Mann, B. & Ryder, N. Language models are few-shot learners. Adv. Neural Inf. Process. Syst. (2020).
  2. Chen, T., Kornblith, S., Norouzi, M. & Hinton, G. A Simple Framework for Contrastive Learning of Visual Representations. Proc. 37th Int. Conf. Mach. Learn., PMLR 119, 1597–1607 (2020).
  3. Lilian Weng, J. W. K. Self-Supervised Learning: Self-Prediction and Contrastive Learning. Adv. Neural Inf. Proc. Syst. (2021).
  4. Goodfello w, I. J. et al. Generative Adversarial Networks. Preprint at https://community.unix.com/uploads/short-url/oXsmq2VZ9hc2X6hwPRXZRMGbV20.pdf (2014).
  5. Donahue J. & Simonyan K. Large scale adversarial representation learning. Adv. Neural Inf. Process. Syst. (2019).
  6. Grill J. B., Strub F., Altché F. & Tallec C. Bootstrap your own latent-a new approach to self-supervised learning. Adv. Neural Inf. Proc. Syst. 33, (2020).
  7. Chen, X. & He, K. Exploring Simple Siamese Representation Learning. Proc. IEEE/CVF Conf. Comput. Vis. Pattern Recognit. (CVPR), 2021, 15750–15758 (2021).
  8. Pathak, D., Krahenbuhl, P., Donahue, J., Darrell, T. & Efros, A. A. Context Encoders: Feature Learning by Inpainting. Proc. IEEE Conf. Comput. Vis. Pattern Recognit. (CVPR) 2016, 2536–2544 (2016).
  9. He, K. et al. Masked Autoencoders Are Scalable Vision Learners. Proc. IEEE/CVF Conf. Comput. Vis. Pattern Recognit. (CVPR) 2022, 16000–16009 (2022).
  10. Vu, Y. N. T., Tsue, T., Su, J. & Singh, S. An improved mammography malignancy model with self-supervised learning. Med. Imaging 2021: Comput-Aided Diagn. 11597, 210–216 (2021).
  11. Hao, H., Didari, S., Woo, J. O., Moon, H. & Bangert, P. Highly Efficient Representation and Active Learning Framework for Imbalanced Data and its Application to COVID-19 X-Ray Classification. Conference on Neural Information Processing Systems (NeurIPS 2021) (2021).
  12. Dehaene, O., Camara, A., Moindrot, O., de Lavergne, A. & Courtiol, P. Self-Supervision Closes the Gap Between Weak and Strong Supervision in Histology. in ML4H 2020 NeurIPS workshop (2020).
  13. Kotar, K., Ilharco, G. & Schmidt, L. Contrasting contrastive self-supervised representation learning pipelines. Proc. Estonian Acad. Sci. Biol. Ecol.
  14. Cole, E., Yang, X., Wilber, K., Aodha, O. M. & Belongie, S. When Does Contrastive Visual Representation Learning Work? Proc. IEEE/CVF Conf. Comput. Vis. Pattern Recognit. (CVPR) 2022, 14755–14764 (2022).
  15. Azizi, S., Mustafa, B., Ryan, F. & Beaver, Z. Big self-supervised models advance medical image classification. Proc. Estonian Acad. Sci. Biol. Ecol.
  16. Shi, Y., Siddharth, N., Torr, P. H. S. & Kosiorek, A. R. Adversarial Masking for Self-Supervised Learning. In International Conference on Machine Learning, 20026–20040. (2022).
  17. Van Gansbeke, X. & Vandenhende, S. Revisiting contrastive methods for unsupervised learning of visual representations. Adv. Neural Inf. Process. Syst. 34, 16238–16250 (2021).
  18. Sowrirajan, H., Yang, J., Ng, A. Y. & Rajpurkar, P. MoCo-CXR: MoCo Pre-training Improves Representation and Transferability of Chest X-ray Models. Proc. Mach. Learn. Res. 143, 727–743 (2021).
  19. Bao, W., Jin, Y., Huang, C. & Peng, W. CT Image Classification of Invasive Depth of Gastric Cancer based on 3D-DPN Structure. In The 11th International Workshop on Computer Science and Engineering (WCSE 2021) 115–121 (2021).
  20. Kaku, A., Upadhya, S. & Razavian, N. Intermediate layers matter in momentum contrastive self supervised learning. In 35th Conference on Neural Information Processing Systems (NeurIPS 2021). (2021).
  21. Liu, Q. et al. SimTriplet: Simple Triplet Representation Learning with a Single GPU. In Medical Image Computing and Computer Assisted Intervention – MICCAI 2021 102–112 (2021). · DOI · Paper page

Cited by

Sorted by citations

Authors
Huang, S.-C., Pareek, A., Jensen, M., Lungren, M. P., Yeung, S., & Chaudhari, A. S.
Affiliations
  • Stanford University (US)
  • Stanford Medicine (US)
Corresponding author
Huang, Shih-Cheng
Venue
npj Digital Medicine
Published
2023-04-26
Volume
6
Issue
1
Pages
74-74
ISSN
2398-6352 (ISSN-L)
OpenAlex
W4367055910
Cited by
479
References
130
Citations by year
2026: 145 · 2025: 208 · 2024: 102 · 2023: 24
FWCI
10.03
Type
journal article
Language
en
Open access
Locations
  • npj Digital Medicine (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • National Institutes of Health (75N92020C00021, 75N92020C00008, AR077604, EB002524)
  • National Heart, Lung, and Blood Institute (75N92020C00008, 75N92020C00021, R01HL155410)
  • National Institute of Arthritis and Musculoskeletal and Skin Diseases (R01AR077604, R01AR079431)
  • National Institute of Biomedical Imaging and Bioengineering (P41EB027060, R01EB002524)
  • U.S. National Library of Medicine (R01LM012966)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Domain Adaptation and Few-Shot Learning
  • Health Sciences › Medicine › Health Informatics › Artificial Intelligence in Healthcare and Education
  • Physical Sciences › Computer Science › Computer Vision and Pattern Recognition › Medical Image Segmentation Techniques
Keywords
self-supervised learning, medical image classification, diagnostic imaging, unlabeled data, implementation guidelines, deep learning, limited labeled data

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-07.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-07.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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