Deep Generative Classification of Blood Cell Morphology

TL;DR

CytoDiffusion is a diffusion-based classifier for blood cell morphology that achieves high accuracy, robustness, and interpretability, surpassing existing models in anomaly detection, domain shift resistance, and low-data performance, with the ability to generate realistic synthetic images.

Contribution

We introduce CytoDiffusion, a novel diffusion-based model that improves blood cell classification by integrating anomaly detection, interpretability, and synthetic image generation, setting new benchmarks in medical image analysis.

Findings

Outperforms state-of-the-art models in anomaly detection (AUC 0.990)

Demonstrates robustness to distributional shifts (85.85% accuracy)

Excels in low-data regimes (95.88% accuracy)

Abstract

Accurate classification of haematological cells is critical for diagnosing blood disorders, but presents significant challenges for machine automation owing to the complexity of cell morphology, heterogeneities of biological, pathological, and imaging characteristics, and the imbalance of cell type frequencies. We introduce CytoDiffusion, a diffusion-based classifier that effectively models blood cell morphology, combining accurate classification with robust anomaly detection, resistance to distributional shifts, interpretability, data efficiency, and superhuman uncertainty quantification. Our approach outperforms state-of-the-art discriminative models in anomaly detection (AUC 0.990 vs. 0.918), resistance to domain shifts (85.85% vs. 74.38% balanced accuracy), and performance in low-data regimes (95.88% vs. 94.95% balanced accuracy). Notably, our model generates synthetic blood cell images that are nearly indistinguishable from real images, as demonstrated by an authenticity test in which expert haematologists achieved only 52.3% accuracy (95% CI: [50.5%, 54.2%]) in distinguishing real from generated images. Furthermore, we enhance model explainability through the generation of directly interpretable counterfactual heatmaps. Our comprehensive evaluation framework, encompassing these multiple performance dimensions, establishes a new benchmark for medical image analysis in haematology, ultimately enabling improved diagnostic accuracy in clinical settings. Our code is available at https://github.com/CambridgeCIA/CytoDiffusion.