Abstract
Using large, multi-national datasets for high-performance medical imaging AI systems requires innovation in privacy-preserving machine learning so models can train on sensitive data without requiring data transfer. Here we present PriMIA (Privacy-preserving Medical Image Analysis), a free, open-source software framework for differentially private, securely aggregated federated learning and encrypted inference on medical imaging data. We test PriMIA using a real-life case study in which an expert-level deep convolutional neural network classifies paediatric chest X-rays; the resulting model’s classification performance is on par with locally, non-securely trained models. We theoretically and empirically evaluate our framework’s performance and privacy guarantees, and demonstrate that the protections provided prevent the reconstruction of usable data by a gradient-based model inversion attack. Finally, we successfully employ the trained model in an end-to-end encrypted remote inference scenario using secure multi-party computation to prevent the disclosure of the data and the model.
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Data availability
The paediatric pneumonia dataset is publicly available from Mendeley Data at https://doi.org/10.17632/rscbjbr9sj.3. The MedNIST dataset was assembled by B. J. Erickson (Department of Radiology, Mayo Clinic) and is available at https://github.com/Project-MONAI/MONAI/. The MSD Liver Segmentation Dataset is available at http://medicaldecathlon.com. test sets 1 and 2 contain confidential patient information and cannot be shared publicly. Source data are provided with this paper.
Code availability
The current version of the PriMIA source code is publicly available at https://github.com/gkaissis/PriMIA and permanently archived at https://doi.org/10.5281/zenodo.454559918. PriMIA includes source code from PySyft (https://github.com/OpenMined/PySyft), PyGrid (https://github.com/OpenMined/PyGrid) and Opacus (https://github.com/pytorch/opacus) re-used under open-source licence terms.
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Acknowledgements
We acknowledge funding from the following sources, funders played no role in the design of the study, the preparation of the manuscript or the decision to publish. The Technical University of Munich, School of Medicine Clinician Scientist Programme (KKF), project reference H14 (G.K.). German Research Foundation, SPP2177/1, German Cancer Consortium (DKTK) and TUM Foundation, Technical University of Munich (R.B. and G.K.). European Community Seventh Framework Programme (FP7/2007-2013 grant no. 339563 – CryptoCloud) and FUI ANBLIC Project (T.R.). UK Research and Innovation London Medical Imaging & Artificial Intelligence Centre for Value Based Healthcare (D.R. and G.K.). Technical University Munich/ Imperial College London Joint Academy of Doctoral Studies (D.U.). We thank B. Farkas for creating Figures 1 and 2 as well as the PriMIA logo; P. Cason and H. Emanuel for assisting with PyGrid debugging, M. Lau for his input, D. Testuggine for his input on differentially private gradient descent, M. Jay for helping with PySyft debugging, N. Remerscheid for his work on the liver segmentation case study, the PySyft and PyGrid development teams for their foundational work and the OpenMined community for their scientific input, contributions and discussion.
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Contributions
G.K. conceived and coordinated the project, evaluated the chest radiography data, helped with PriMIA programming and wrote the paper. A.Z. conceived and developed PriMIA, oversaw PriMIA development, trained the models, performed data analysis and wrote the paper. J.P.-P. helped with project management, oversaw the security and cryptography aspects of PriMIA, supervised model inversion attacks and helped write the paper. T.R. designed and developed PySyft and PyGrid, designed and implemented the AriaNN FSS protocol, helped with PriMIA programming and performed inference latency assessment. D.U. performed the model inversion attacks and helped write the paper. A.T. conceived the OpenMined project, designed and developed PySyft and PyGrid, provided project guidance and assistance and helped with PriMIA development. I.D.L.C.J. developed PyGrid and helped with PriMIA programming. J.M. provided project guidance and prototype code. F.J. performed data curation and helped with data analysis on the chest radiographs. M.-M.S. performed data curation and evaluated the chest radiography data. A.S. and M.M. provided project management, support and guidance. D.R. provided oversight, project management, support, guidance and scientific input, and helped write the paper. R.B. provided oversight, project management, support and guidance, helped with data procurement, provided scientific input and helped write the paper. All authors proof-read and accepted the final version of the paper.
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Kaissis, G., Ziller, A., Passerat-Palmbach, J. et al. End-to-end privacy preserving deep learning on multi-institutional medical imaging. Nat Mach Intell 3, 473–484 (2021). https://doi.org/10.1038/s42256-021-00337-8
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DOI: https://doi.org/10.1038/s42256-021-00337-8
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