PRIMIS: Privacy-preserving medical image sharing via deep sparsifying transform learning with obfuscation

Authors:
raw_author_name: Isaac Shiri
raw_affiliation_string: Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland
raw_author_name: Behrooz Razeghi
raw_affiliation_string: Department of Computer Science, University of Geneva, Switzerland; Idiap Research Institute, Switzerland
raw_author_name: Sohrab Ferdowsi
raw_affiliation_string: Department of Radiology and Medical Informatics, University of Geneva, Switzerland
raw_author_name: Yazdan Salimi
raw_affiliation_string: Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland
raw_author_name: Deniz Gündüz
raw_affiliation_string: Department of Electrical and Electronic Engineering, Imperial College London, UK
raw_author_name: Douglas Teodoro
raw_affiliation_string: Department of Radiology and Medical Informatics, University of Geneva, Switzerland
raw_author_name: Slava Voloshynovskiy
raw_affiliation_string: Department of Computer Science, University of Geneva, Switzerland
raw_author_name: Habib Zaidi
raw_affiliation_string: Department of Nuclear Medicine and Molecular Imaging, University of Groningen, The Netherlands; Department of Nuclear Medicine, University of Southern Denmark, Denmark; Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland; University Research and Innovation Center, Óbuda University, Budapest, Hungary

Abstract: The primary objective of our study is to address the challenge of confidentially sharing medical images across different centers. This is often a critical necessity in both clinical and research environments, yet restrictions typically exist due to privacy concerns. Our aim is to design a privacy-preserving data-sharing mechanism that allows medical images to be stored as encoded and obfuscated representations in the public domain without revealing any useful or recoverable content from the images. In tandem, we aim to provide authorized users with compact private keys that could be used to reconstruct the corresponding images.Our approach involves utilizing a neural auto-encoder. The convolutional filter outputs are passed through sparsifying transformations to produce multiple compact codes. Each code is responsible for reconstructing different attributes of the image. The key privacy-preserving element in this process is obfuscation through the use of specific pseudo-random noise. When applied to the codes, it becomes computationally infeasible for an attacker to guess the correct representation for all the codes, thereby preserving the privacy of the images.The proposed framework was implemented and evaluated using chest X-ray images for different medical image analysis tasks, including classification, segmentation, and texture analysis. Additionally, we thoroughly assessed the robustness of our method against various attacks using both supervised and unsupervised algorithms.This study provides a novel, optimized, and privacy-assured data-sharing mechanism for medical images, enabling multi-party sharing in a secure manner. While we have demonstrated its effectiveness with chest X-ray images, the mechanism can be utilized in other medical images modalities as well.