High-resolution medical image synthesis using progressively grown generative adversarial networks

TL;DR

This paper demonstrates that progressively grown GANs can generate high-resolution, realistic medical images, preserving fine details like vessels and tumors, with potential applications in augmentation and classification.

Contribution

The study shows that progressive growing of GANs effectively produces high-resolution medical images with preserved pathological details, advancing medical image synthesis.

Findings

Generated realistic fundus and MRI images at high resolution

Preserved fine pathological details such as vessels and tumor heterogeneity

Potential for applications in image augmentation and unsupervised classification

Abstract

Generative adversarial networks (GANs) are a class of unsupervised machine learning algorithms that can produce realistic images from randomly-sampled vectors in a multi-dimensional space. Until recently, it was not possible to generate realistic high-resolution images using GANs, which has limited their applicability to medical images that contain biomarkers only detectable at native resolution. Progressive growing of GANs is an approach wherein an image generator is trained to initially synthesize low resolution synthetic images (8x8 pixels), which are then fed to a discriminator that distinguishes these synthetic images from real downsampled images. Additional convolutional layers are then iteratively introduced to produce images at twice the previous resolution until the desired resolution is reached. In this work, we demonstrate that this approach can produce realistic medical images in two different domains; fundus photographs exhibiting vascular pathology associated with retinopathy of prematurity (ROP), and multi-modal magnetic resonance images of glioma. We also show that fine-grained details associated with pathology, such as retinal vessels or tumor heterogeneity, can be preserved and enhanced by including segmentation maps as additional channels. We envisage several applications of the approach, including image augmentation and unsupervised classification of pathology.