Multi-step retrieval and reasoning improves radiology question answering with large language models.

ABSTRACT: Large language models (LLMs) show promise for radiology decision support, yet conventional retrieval-augmented generation (RAG) relies on single-step retrieval and struggles with complex reasoning. We introduce radiology Retrieval and Reasoning (RaR), a multi-step retrieval framework that iteratively summarizes clinical questions, retrieves evidence, and synthesizes answers. We evaluated 25 LLMs spanning general-purpose, reasoning-optimized, and clinically fine-tuned models (0.5B → 670B parameters) on 104 expert-curated radiology questions and an independent set of 65 real radiology board-exam questions. RaR significantly improved mean diagnostic accuracy versus zero-shot prompting (75% vs. 67%; P = 1.1 × 10^-7) and conventional online RAG (75% vs. 69%; P = 1.9 × 10^-6)

SUBMITTER: Wind S 

PROVIDER: S-EPMC12749912 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature