Identifying Imaging Follow-Up in Radiology Reports: A Comparative Analysis of Traditional ML and LLM Approaches
Summary
Radiology reports often recommend follow-up imaging, but these recommendations frequently go unacted upon, and hospitals rarely track whether the recommended exam was ever done. Progress on automating this tracking has been held back by a shortage of suitable annotated data. The authors built such a corpus from a large de-identified clinical database. They chose CT and MRI "index" reports that recommend follow-up for a new lesion, then gathered every later report for the same patient as "candidate" reports. Medical students marked the earliest candidate that actually re-examines the flagged finding, with a radiologist resolving hard cases.
On this benchmark the authors compared:
- classical classifiers (LR, SVM),
- Longformer,
- a fully fine-tuned Llama3-8B-Instruct,
- prompted GPT-4o and GPT-OSS-20B, each in a plain setup and in an optimized one that restricts the input to metadata, recommendation sentences and nearby context.
The optimized generative models scored best, coming close to human agreement. The simple linear models remained competitive, which makes them practical low-cost options for clinical deployment.
Key points
- Corpus size and sources: 6,393 reports from 586 patients, made up of 586 index reports and 5,807 candidates (about 9.9 per index). The source pool held 7 million reports from 959,382 patients covering 2007–2020.
- Index report selection: Only CT and MRI index reports describing new lesions were included, spanning six body sites: the thyroid, pancreas, adrenal glands, liver, kidneys and lungs. Selection used an SVM recommendation-sentence classifier (0.87 F1) plus a BERT-based entity extractor.
- Annotation: Inter-annotator agreement was 0.846 F1. 239 cases were double-annotated and 347 single-annotated. A follow-up report was found for 417 patients (71.3%).
- Results: F1 scores were 0.832 for GPT-4o (Advanced), 0.828 for GPT-OSS-20B (Advanced), 0.776 for LR and 0.775 for SVM. 95% confidence intervals were obtained by bootstrapping.
- Code: Available at github.com/uw-bionlp/ReportMatcher.
Cite
@inproceedings{park2026identifying,
title = {{Identifying Imaging Follow-Up in Radiology Reports: A Comparative Analysis of Traditional ML and LLM Approaches}},
author = {Park, Namu and Ramachandran, Giridhar Kaushik and Lybarger, Kevin and Xia, Fei and Uzuner, Özlem and Gunn, Martin and Yetisgen, Meliha},
booktitle = {Proceedings of the Fifteenth Language Resources and Evaluation Conference},
year = {2026},
doi = {10.63317/5eve2chrhdy5},
url = {https://doi.org/10.63317/5eve2chrhdy5}
}References
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