EMIXER: End-to-end Multimodal X-ray Generation via Self-supervision

TL;DR

EMIXER is an end-to-end multimodal generative model that synthesizes X-ray images and reports conditioned on diagnosis labels, leveraging self-supervision to improve clinical data augmentation and machine learning tasks.

Contribution

This paper introduces EMIXER, a novel multimodal generative adversarial network that jointly synthesizes X-ray images and reports with self-supervision, enhancing clinical data augmentation.

Findings

Synthetic data improves COVID-19 X-ray classification by 5.94%

Generated images and reports are validated by radiologists

Data augmentation boosts report generation and classification performance

Abstract

Deep generative models have enabled the automated synthesis of high-quality data for diverse applications. However, the most effective generative models are specialized to data from a single domain (e.g., images or text). Real-world applications such as healthcare require multi-modal data from multiple domains (e.g., both images and corresponding text), which are difficult to acquire due to limited availability and privacy concerns and are much harder to synthesize. To tackle this joint synthesis challenge, we propose an End-to-end MultImodal X-ray genERative model (EMIXER) for jointly synthesizing x-ray images and corresponding free-text reports, all conditional on diagnosis labels. EMIXER is an conditional generative adversarial model by 1) generating an image based on a label, 2) encoding the image to a hidden embedding, 3) producing the corresponding text via a hierarchical decoder from the image embedding, and 4) a joint discriminator for assessing both the image and the corresponding text. EMIXER also enables self-supervision to leverage vast amount of unlabeled data. Extensive experiments with real X-ray reports data illustrate how data augmentation using synthesized multimodal samples can improve the performance of a variety of supervised tasks including COVID-19 X-ray classification with very limited samples. The quality of generated images and reports are also confirmed by radiologists. We quantitatively show that EMIXER generated synthetic datasets can augment X-ray image classification, report generation models to achieve 5.94% and 6.9% improvement on models trained only on real data samples. Taken together, our results highlight the promise of state of generative models to advance clinical machine learning.