Using GPT-4o for CAD-RADS feature extraction and categorization with free-text coronary CT Angiography reports (Preprint)

Abstract Background Despite the Coronary Artery Reporting and Data System (CAD-RADS) providing a standardized approach, radiologists continue to favor free-text reports. This preference creates significant challenges for data extraction and analysis in longitudinal studies, potentially limiting large-scale research and quality assessment initiatives. Objective To evaluate the ability of the generative pre-trained transformer (GPT)-4o model to convert real-world coronary computed tomography angiography (CCTA) free-text reports into structured data and automatically identify CAD-RADS categories and P categories. Methods This retrospective study analyzed CCTA reports from January 2024 and July 2024. A subset of 25 reports was used for prompt engineering to instruct the large language models (LLMs) in extracting CAD-RADS categories, P categories, and the presence of myocardial bridges and noncalcified plaques. Reports were processed using the GPT-4o API (application programming interface) and custom Python scripts. The ground truth was established by radiologists based on the CAD-RADS 2.0 guidelines. Model performance was assessed using accuracy, sensitivity, specificity, and F 1 -score. Intrarater reliability was assessed using Cohen κ coefficient. Results Among 999 patients (median age 66 y, range 58‐74; 650 males), CAD-RADS categorization showed accuracy of 0.98‐1.00 (95% CI 0.9730‐1.0000), sensitivity of 0.95‐1.00 (95% CI 0.9191‐1.0000), specificity of 0.98‐1.00 (95% CI 0.9669‐1.0000), and F 1 -score of 0.96‐1.00 (95% CI 0.9253‐1.0000). P categories demonstrated accuracy of 0.97‐1.00 (95% CI 0.9569‐0.9990), sensitivity from 0.90 to 1.00 (95% CI 0.8085‐1.0000), specificity from 0.97 to 1.00 (95% CI 0.9533‐1.0000), and F 1 -score from 0.91 to 0.99 (95% CI 0.8377‐0.9967). Myocardial bridge detection achieved an accuracy of 0.98 (95% CI 0.9680‐0.9870), and noncalcified coronary plaques detection showed an accuracy of 0.98 (95% CI 0.9680‐0.9870). Cohen κ values for all classifications exceeded 0.98. Conclusions The GPT-4o model efficiently and accurately converts CCTA free-text reports into structured data, excelling in CAD-RADS classification, plaque burden assessment, and detection of myocardial bridges and calcified plaques.