FireGNN: Neuro-Symbolic Graph Neural Networks with Trainable Fuzzy Rules for Interpretable Medical Image Classification
Prajit Sengupta, Islem Rekik
TL;DR
FireGNN tackles the interpretability bottleneck in medical image classification by integrating trainable fuzzy rules over local graph topology into GNNs. The method formulates topological features $f_u=[d(u), C(u), L(u)]$ and learns thresholds $\theta_i$ and sharpness $\alpha_i$ for three fuzzy rules, whose activations $r_i(u)=\sigma(\alpha_i(f_u[i]-\theta_i))$ are fused with neural embeddings through a gating mechanism to yield interpretable predictions. Empirically, FireGNN achieves strong performance across six datasets (five MedMNIST variants and MorphoMNIST) and provides intrinsic explanations via rule activations, outperforming auxiliary self-supervised baselines. While demonstrating clear benefits for trustworthy medical AI, the approach incurs higher computational costs and currently uses a compact rule set, pointing to future work on richer rule vocabularies and efficiency improvements.
Abstract
Medical image classification requires not only high predictive performance but also interpretability to ensure clinical trust and adoption. Graph Neural Networks (GNNs) offer a powerful framework for modeling relational structures within datasets; however, standard GNNs often operate as black boxes, limiting transparency and usability, particularly in clinical settings. In this work, we present an interpretable graph-based learning framework named FireGNN that integrates trainable fuzzy rules into GNNs for medical image classification. These rules embed topological descriptors - node degree, clustering coefficient, and label agreement - using learnable thresholds and sharpness parameters to enable intrinsic symbolic reasoning. Additionally, we explore auxiliary self-supervised tasks (e.g., homophily prediction, similarity entropy) as a benchmark to evaluate the contribution of topological learning. Our fuzzy-rule-enhanced model achieves strong performance across five MedMNIST benchmarks and the synthetic dataset MorphoMNIST, while also generating interpretable rule-based explanations. To our knowledge, this is the first integration of trainable fuzzy rules within a GNN. Source Code: https://github.com/basiralab/FireGNN
