MedEdit: Counterfactual Diffusion-based Image Editing on Brain MRI

TL;DR

MedEdit is a novel diffusion-based model for realistic, pathology-specific medical image editing that preserves original scan integrity and outperforms existing methods in generating plausible biomedical counterfactuals.

Contribution

We introduce MedEdit, a conditional diffusion model that effectively models disease effects while maintaining scan fidelity, advancing biomedical image editing capabilities.

Findings

Outperforms state-of-the-art methods by 45-61% in quantitative metrics.

Generated images are clinically indistinguishable from real scans.

Clinician evaluation confirms high realism of edited images.

Abstract

Denoising diffusion probabilistic models enable high-fidelity image synthesis and editing. In biomedicine, these models facilitate counterfactual image editing, producing pairs of images where one is edited to simulate hypothetical conditions. For example, they can model the progression of specific diseases, such as stroke lesions. However, current image editing techniques often fail to generate realistic biomedical counterfactuals, either by inadequately modeling indirect pathological effects like brain atrophy or by excessively altering the scan, which disrupts correspondence to the original images. Here, we propose MedEdit, a conditional diffusion model for medical image editing. MedEdit induces pathology in specific areas while balancing the modeling of disease effects and preserving the integrity of the original scan. We evaluated MedEdit on the Atlas v2.0 stroke dataset using Frechet Inception Distance and Dice scores, outperforming state-of-the-art diffusion-based methods such as Palette (by 45%) and SDEdit (by 61%). Additionally, clinical evaluations by a board-certified neuroradiologist confirmed that MedEdit generated realistic stroke scans indistinguishable from real ones. We believe this work will enable counterfactual image editing research to further advance the development of realistic and clinically useful imaging tools.