Liwen Sun
2026
Linking Knowledge to Care: Knowledge Graph-Augmented Medical Follow-Up Question Generation
Liwen Sun | Xiang Yu | Ming Tan | Zhuohao Chen | Anqi Cheng | Ashutosh Joshi | Chenyan Xiong
Findings of the Association for Computational Linguistics: EACL 2026
Liwen Sun | Xiang Yu | Ming Tan | Zhuohao Chen | Anqi Cheng | Ashutosh Joshi | Chenyan Xiong
Findings of the Association for Computational Linguistics: EACL 2026
Clinical diagnosis is time-consuming, requiring intensive interactions between patients and medical professionals. While large language models (LLMs) could ease the pre-diagnostic workload, their limited domain knowledge hinders effective medical question generation. We introduce a Knowledge Graph-augmented LLM with active in-context learning to generate relevant and important follow-up questions, KG-Followup, serving as a critical module for the pre-diagnostic assessment. The structured medical domain knowledge graph serves as a seamless patch-up to provide professional domain expertise upon which the LLM can reason. Experiments demonstrate that KG-Followup outperforms state-of-the-art methods by 5% - 8% on relevant benchmarks.
2025
1-2-3 Check: Enhancing Contextual Privacy in LLM via Multi-Agent Reasoning
Wenkai Li | Liwen Sun | Zhenxiang Guan | Xuhui Zhou | Maarten Sap
Proceedings of the The First Workshop on LLM Security (LLMSEC)
Wenkai Li | Liwen Sun | Zhenxiang Guan | Xuhui Zhou | Maarten Sap
Proceedings of the The First Workshop on LLM Security (LLMSEC)
Addressing contextual privacy concerns remains challenging in interactive settings where large language models (LLMs) process information from multiple sources. Building on the theory of contextual integrity, we introduce a multi-agent framework that decomposes privacy reasoning into specialized subtasks—extraction, classification—reducing the information load on any single agent while enabling iterative validation and more reliable adherence to contextual privacy norms. Experiments on the ConfAIde benchmark with two LLMs (GPT-4, Llama3) demonstrate that our multi-agent system substantially reduces private information leakage (36% reduction) while maintaining the fidelity of public content compared to a single-agent system, showing the promise of multi-agent frameworks towards contextual privacy with LLMs.
Fact-Aware Multimodal Retrieval Augmentation for Accurate Medical Radiology Report Generation
Liwen Sun | James Jialun Zhao | Wenjing Han | Chenyan Xiong
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Liwen Sun | James Jialun Zhao | Wenjing Han | Chenyan Xiong
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Multimodal foundation models hold significant potential for automating radiology report generation, thereby assisting clinicians in diagnosing cardiac diseases. However, generated reports often suffer from serious factual inaccuracy. In this paper, we introduce a fact-aware multimodal retrieval-augmented pipeline in generating accurate radiology reports (FactMM-RAG). We first leverage RadGraph to mine factual report pairs, then integrate factual knowledge to train a universal multimodal retriever. Given a radiology image, our retriever can identify high-quality reference reports to augment multimodal foundation models, thus enhancing the factual completeness and correctness of report generation. Experiments on two benchmark datasets demonstrate that our multimodal retriever significantly outperforms other state-of-the-art retrievers on both language generation and radiology-specific metrics, up to 6.5% and 2% score in F1CheXbert and F1RadGraph. Further analysis indicates that employing our factually-informed training strategy imposes an effective supervision signal, without relying on explicit diagnostic label guidance, and successfully propagate fact-aware capabilities from the multimodal retriever to the multimodal foundation model in radiology report generation.