Evidence Hub

Retrieval-Augmented Generation in Radiology: A Scoping Review of Architectures, Imaging Applications, and Directions for Equitable Deployment

Wong MYH, Li H, Langlotz C, Sheng B

Journal of imaging informatics in medicine, 2026

Abstract

Large language models (LLMs) are increasingly explored in radiology, yet concerns persist regarding hallucination and lack of factual grounding. Retrieval-augmented generation (RAG) seeks to address these limitations by coupling generative models with external knowledge retrieval. We conducted a scoping review to characterize how RAG systems have been applied in radiology and medical imaging. A systematic search of PubMed, Embase, Scopus, IEEE Xplore, and arXiv identified 45 studies implementing RAG-based approaches in radiology-related tasks. In terms of clinical tasks, RAG was most commonly applied to radiology report generation and question answering. Dense retrieval strategies predominated, while sparse, hybrid and proprietary retrieval approaches were less frequent. External knowledge sources most frequently comprised biomedical literature databases and clinical guidelines. Applications were heavily skewed toward chest radiography and X-ray-based tasks, with relatively few studies addressing CT, MRI, PET, ultrasound, or under-represented subspecialties such as pediatric radiology and neuroradiology. Most comparative studies reported task-specific performance gains with RAG over non-retrieval baselines, and a small subset reported performance comparable to trained radiologists or state-of-the-art models. However, hallucinations and errors persisted, and heterogeneity across studies limited the generalizability of these findings. Evaluation practices largely relied on…

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free