URCDM: Ultra-Resolution Image Synthesis in Histopathology
Sarah Cechnicka, James Ball, Matthew Baugh, Hadrien Reynaud, Naomi Simmonds, Andrew P. T. Smith, Catherine Horsfield, Candice Roufosse, Bernhard Kainz
TL;DR
The paper tackles the challenge of generating coherent, ultra-high-resolution histopathology WSIs that preserve hierarchical structure across magnifications, addressing memory and privacy issues of patch-based diffusion. It introduces Ultra-Resolution Cascaded Diffusion Models (URCDMs), a three-stage cascade of diffusion processes (nine CDMs total) that progressively produce $1024.0\times1024.0$, $6400.0\times6400.0$, and $41344.0\times41344.0$ pixel WSIs, with stage-wise conditioning and inpainting. Evaluations on GLIOMA, BREAST, and KIDNEY show URCDMs outperforming state-of-the-art baselines on FID-10k, pFID-50k, and IP/IR, and expert blinding studies indicate generated WSIs are largely indistinguishable from real ones, albeit with some artefact sensitivity in certain cases. The approach promises privacy-preserving, gigapixel histopathology data across scales with potential impact on education and downstream modeling, while future work will target efficiency, a shared multi-magnification CDM, and multi-modal extensions.
Abstract
Diagnosing medical conditions from histopathology data requires a thorough analysis across the various resolutions of Whole Slide Images (WSI). However, existing generative methods fail to consistently represent the hierarchical structure of WSIs due to a focus on high-fidelity patches. To tackle this, we propose Ultra-Resolution Cascaded Diffusion Models (URCDMs) which are capable of synthesising entire histopathology images at high resolutions whilst authentically capturing the details of both the underlying anatomy and pathology at all magnification levels. We evaluate our method on three separate datasets, consisting of brain, breast and kidney tissue, and surpass existing state-of-the-art multi-resolution models. Furthermore, an expert evaluation study was conducted, demonstrating that URCDMs consistently generate outputs across various resolutions that trained evaluators cannot distinguish from real images. All code and additional examples can be found on GitHub.
