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arXiv 2410.03334cs.CVcs.AI
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一张X光片抵15个特征:用于可解释放射学报告生成的稀疏自编码器

An X-Ray Is Worth 15 Features: Sparse Autoencoders for Interpretable Radiology Report Generation

Microsoft Research(微软研究院);Hawkes Centre(霍克斯中心);UCL(伦敦大学学院)

Ahmed Abdulaal, Hugo Fry, Nina Montaña-Brown, Ayodeji Ijishakin, Jack Gao, Stephanie Hyland, Daniel C. Alexander, Daniel C. Castro

AI总结:

针对现有视觉-语言模型在放射学报告生成中存在幻觉、可解释性差且微调成本高的问题,提出基于稀疏自编码器的SAE-Rad方法,无需大模型微调即可生成可解释的报告,在MIMIC-CXR上指标达前沿水平且训练算力消耗更低。

摘要:

放射科服务正面临前所未有的需求,推动了放射学报告自动生成研究的热度。现有视觉-语言模型(VLM)存在幻觉问题、缺乏可解释性,且微调成本高昂。我们提出SAE-Rad,该方法利用稀疏自编码器(SAE,即sparse autoencoders)将预训练视觉Transformer的潜在表征分解为人类可解释的特征。我们的混合架构结合了前沿的SAE技术进展,在保持稀疏性的同时实现准确的潜在重构。我们借助现成的语言模型,将真实报告提炼为每个SAE特征对应的放射学描述,再将这些描述汇编为每张图像的完整报告,无需针对该任务微调大模型。据我们所知,SAE-Rad是首个明确将机制可解释性技术用于下游多模态推理任务的方法。在MIMIC-CXR数据集上,SAE-Rad的放射学专项指标与前沿模型相当,而训练所需计算资源大幅减少。定性分析显示,SAE-Rad能学习有意义的视觉概念,生成的报告与专家解读高度契合。我们的结果表明,SAE可增强医疗领域的多模态推理,为现有VLM提供更具可解释性的替代方案。

英文摘要:

Radiological services are experiencing unprecedented demand, leading to increased interest in automating radiology report generation. Existing Vision-Language Models (VLMs) suffer from hallucinations, lack interpretability, and require expensive fine-tuning. We introduce SAE-Rad, which uses sparse autoencoders (SAEs) to decompose latent representations from a pre-trained vision transformer into human-interpretable features. Our hybrid architecture combines state-of-the-art SAE advancements, achieving accurate latent reconstructions while maintaining sparsity. Using an off-the-shelf language model, we distil ground-truth reports into radiological descriptions for each SAE feature, which we then compile into a full report for each image, eliminating the need for fine-tuning large models for this task. To the best of our knowledge, SAE-Rad represents the first instance of using mechanistic interpretability techniques explicitly for a downstream multi-modal reasoning task. On the MIMIC-CXR dataset, SAE-Rad achieves competitive radiology-specific metrics compared to state-of-the-art models while using significantly fewer computational resources for training. Qualitative analysis reveals that SAE-Rad learns meaningful visual concepts and generates reports aligning closely with expert interpretations. Our results suggest that SAEs can enhance multimodal reasoning in healthcare, providing a more interpretable alternative to existing VLMs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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