M3Net: A Macro-to-Meso-to-Micro Clinical-inspired Hierarchical 3D Network for Pulmonary Nodule Classification

TL;DR

M3Net is a hierarchical 3D neural network inspired by radiologists' diagnostic workflow, integrating multi-scale contextual information to improve pulmonary nodule classification accuracy.

Contribution

The paper introduces M3Net, a novel multi-scale 3D network that enhances interpretability and performance in pulmonary nodule classification by mimicking clinical diagnostic processes.

Findings

Achieves state-of-the-art accuracy of 86.96% on LIDC-IDRI dataset.

Outperforms baseline models by over 3% in accuracy.

Demonstrates robustness and clinical relevance in pulmonary nodule classification.

Abstract

The accurate classification of benign and malignant pulmonary nodules in CT scans is critical for early lung cancer screening, yet remains challenging due to the multi-scale and heterogeneous nature of pulmonary nodules. While deep learning offers potential for auxiliary diagnosis, most existing models act as "black boxes", lacking the transparency and explainability required for trustworthy clinical integration. To address this issue, we propose M3Net, a novel 3D network for pulmonary nodule classification inspired by the hierarchical diagnostic workflow of radiologists, which integrates multi-scale contextual information from fine-grained structures to global anatomical relationships. Our framework constructs a progressive multi-scale input, from fine-grained nodule structures to local semantics and global spatial relationships. M3Net employs scale-specific encoders and ensures cross-scale semantic consistency through latent space projection and mutual information maximization. Extensive experiments on the public LIDC-IDRI dataset and a self-collected clinical dataset (USTC-FHLN) demonstrate that our method achieves state-of-the-art performance, with accuracies of 86.96% and 84.24% respectively, outperforming the best baseline by 3.26% and 2.17%. The results validate that M3Net provides a more robust and clinically relevant solution for pulmonary nodule classification. The code is available at https://github.com/jylEcho/M3-Net.