RadTimeline: Timeline Summarization for Longitudinal Radiological Lung Findings

Sitong Zhou, Meliha Yetisgen, Mari Ostendorf


Abstract
Tracking findings in longitudinal radiology reports is crucial for accurately identifying disease progression, and the time-consuming process would benefit from automatic summarization. This work introduces a structured summarization task, where we frame longitudinal report summarization as a timeline generation task, with dated findings organized in columns and temporally related findings grouped in rows. This structured summarization format enables straightforward comparison of findings across time and facilitates fact-checking against the associated reports. The timeline is generated using a 3-step LLM process of extracting findings, generating group names, and using the names to group the findings. To evaluate such systems, we create RadTimeline, a timeline dataset focused on tracking lung-related radiologic findings in chest-related imaging reports. Experiments on RadTimeline show tradeoffs of different-sized LLMs and prompting strategies. Our results highlight that group name generation as an intermediate step is critical for effective finding grouping. The best configuration has some irrelevant findings but very good recall, and grouping performance is comparable to human annotators.
Anthology ID:
2026.lrec-main.778
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
9920–9939
Language:
URL:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.778/
DOI:
Bibkey:
Cite (ACL):
Sitong Zhou, Meliha Yetisgen, and Mari Ostendorf. 2026. RadTimeline: Timeline Summarization for Longitudinal Radiological Lung Findings. International Conference on Language Resources and Evaluation, main:9920–9939.
Cite (Informal):
RadTimeline: Timeline Summarization for Longitudinal Radiological Lung Findings (Zhou et al., LREC 2026)
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PDF:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.778.pdf