SeMLI-RAG: Semantics-Guided Multimodal Late Interaction for Retrieval-Augmented Radiology Report Generation

Jiawei He, Weibo Feng, Sohrab Ferdowsi, Anthony Yazdani, Boya Zhang, Osman Alperen Çinar-Koraş, Sameh Khattab, Jean-Philippe Corbeil, Henning Müller, Douglas Teodoro


Abstract
The consultation of reference cases in clinical radiology reporting motivates integrating multimodal retrieval-augmented generation (RAG) into automated systems. However, traditional RAG approaches employ single-vector embeddings for indexing, resulting in loss of granular information. Moreover, a semantic gap exists whereby visually similar radiographs often encode distinct pathologies. In this paper, we propose a Semantics-guided Multi-modal Late Interaction RAG (SeMLI-RAG) framework for radiology report generation. Our approach employs a weight-based late interaction strategy for retrieval to capture fine-grained radiographic features. Furthermore, we introduce an image-adaptive RAG to selectively leverage retrieved information, mitigating performance degradation caused by retrieval-induced noise. Experiments on three radiology benchmarks demonstrate that our framework yields consistent improvements over the backbone and RAG baselines across multiple evaluation dimensions. Further analysis shows that improving retrieval granularity and retrieval robustness can both benefit radiology report generation.
Anthology ID:
2026.emnlp-main.2379
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
54040–54055
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2379/
DOI:
Bibkey:
Cite (ACL):
Jiawei He, Weibo Feng, Sohrab Ferdowsi, Anthony Yazdani, Boya Zhang, Osman Alperen Çinar-Koraş, Sameh Khattab, Jean-Philippe Corbeil, Henning Müller, and Douglas Teodoro. 2026. SeMLI-RAG: Semantics-Guided Multimodal Late Interaction for Retrieval-Augmented Radiology Report Generation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 54040–54055, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SeMLI-RAG: Semantics-Guided Multimodal Late Interaction for Retrieval-Augmented Radiology Report Generation (He et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.2379.pdf