Information Bottleneck-based Causal Attention for Multi-label Medical Image Recognition

TL;DR

This paper introduces a novel causal attention mechanism based on the information bottleneck principle to improve multi-label medical image classification by effectively filtering out irrelevant features and enhancing class-specific attention.

Contribution

It proposes a new structural causal model and a Gaussian mixture-based attention method with contrastive causal intervention for better interpretability and accuracy in medical image multi-label classification.

Findings

IBCA outperforms existing methods on Endo and MuReD datasets.

Significant improvements in CR, OR, and mAP metrics.

Effective filtering of class-irrelevant information enhances interpretability.

Abstract

Multi-label classification (MLC) of medical images aims to identify multiple diseases and holds significant clinical potential. A critical step is to learn class-specific features for accurate diagnosis and improved interpretability effectively. However, current works focus primarily on causal attention to learn class-specific features, yet they struggle to interpret the true cause due to the inadvertent attention to class-irrelevant features. To address this challenge, we propose a new structural causal model (SCM) that treats class-specific attention as a mixture of causal, spurious, and noisy factors, and a novel Information Bottleneck-based Causal Attention (IBCA) that is capable of learning the discriminative class-specific attention for MLC of medical images. Specifically, we propose learning Gaussian mixture multi-label spatial attention to filter out class-irrelevant information and capture each class-specific attention pattern. Then a contrastive enhancement-based causal intervention is proposed to gradually mitigate the spurious attention and reduce noise information by aligning multi-head attention with the Gaussian mixture multi-label spatial. Quantitative and ablation results on Endo and MuReD show that IBCA outperforms all methods. Compared to the second-best results for each metric, IBCA achieves improvements of 6.35\% in CR, 7.72\% in OR, and 5.02\% in mAP for MuReD, 1.47\% in CR, and 1.65\% in CF1, and 1.42\% in mAP for Endo.