Utility of Multimodal Large Language Models in Analyzing Chest X-ray with Incomplete Contextual Information

Background: Large language models (LLMs) are gaining use in clinical settings, but their performance can suffer with incomplete radiology reports. We tested whether multimodal LLMs (using text and images) could improve accuracy and understanding in chest radiography reports, making them more effective for clinical decision support. Purpose: To assess the robustness of LLMs in generating accurate impressions from chest radiography reports using both incomplete data and multimodal data. Material and Methods: We used 300 radiology image-report pairs from the MIMIC-CXR database. Three LLMs (OpenFlamingo, MedFlamingo, IDEFICS) were tested in both text-only and multimodal formats. Impressions were first generated from the full text, then tested by removing 20%, 50%, and 80% of the text. The impact of adding images was evaluated using chest x-rays, and model performance was compared using three metrics with statistical analysis. Results: The text-only models (OpenFlamingo, MedFlamingo, IDEFICS) had similar performance (ROUGE-L: 0.39 vs. 0.21 vs. 0.21; F1RadGraph: 0.34 vs. 0.17 vs. 0.17; F1CheXbert: 0.53 vs. 0.40 vs. 0.40), with OpenFlamingo performing best on complete text (p<0.001). Performance declined with incomplete data across all models. However, adding images significantly boosted the performance of MedFlamingo and IDEFICS (p<0.001), equaling or surpassing OpenFlamingo, even with incomplete text. Conclusion: LLMs may produce low-quality outputs with incomplete radiology data, but multimodal LLMs can improve reliability and support clinical decision-making. Keywords: Large language model; multimodal; semantic analysis; Chest Radiography; Clinical Decision Support;