Longitudinal Data and a Semantic Similarity Reward for Chest X-Ray Report Generation

TL;DR

This paper introduces a novel CXR report generation model that uses longitudinal data, section embeddings, and a semantic reward to improve report accuracy and mimic radiologist workflow, showing better results than existing models.

Contribution

The study presents a new CXR report generator that effectively handles cases with or without prior studies and incorporates clinical semantics through a reinforcement learning reward.

Findings

Model generates reports more aligned with radiologists' reports.

Improves diagnostic accuracy over state-of-the-art models.

Handles cases with no prior studies effectively.

Abstract

Radiologists face high burnout rates, partially due to the increasing volume of Chest X-rays (CXRs) requiring interpretation and reporting. Automated CXR report generation holds promise for reducing this burden and improving patient care. While current models show potential, their diagnostic accuracy is limited. Our proposed CXR report generator integrates elements of the radiologist workflow and introduces a novel reward for reinforcement learning. Our approach leverages longitudinal data from a patient's prior CXR study and effectively handles cases where no prior study exist, thus mirroring the radiologist's workflow. In contrast, existing models typically lack this flexibility, often requiring prior studies for the model to function optimally. Our approach also incorporates all CXRs from a patient's study and distinguishes between report sections through section embeddings. Our reward for reinforcement learning leverages CXR-BERT, which forces our model to learn the clinical semantics of radiology reporting. We conduct experiments on publicly available datasets -- MIMIC-CXR and Open-i IU X-ray -- with metrics shown to more closely correlate with radiologists' assessment of reporting. Results from our study demonstrate that the proposed model generates reports that are more aligned with radiologists' reports than state-of-the-art models, such as those utilising large language models, reinforcement learning, and multi-task learning. The proposed model improves the diagnostic accuracy of CXR report generation, which could one day reduce radiologists' workload and enhance patient care. Our Hugging Face checkpoint (https://huggingface.co/aehrc/cxrmate) and code (https://github.com/aehrc/cxrmate) are publicly available.