Region-Grounded Report Generation for 3D Medical Imaging: A Fine-Grained Dataset and Graph-Enhanced Framework
Paper · 2026 · Cong Huy Nguyen, Son Dinh Nguyen, Guanlin Li et al.
Summary
Automatic report writing for volumetric PET/CT scans is hard because the data are large and three-dimensional, annotated corpora are scarce (especially outside English and Chinese), and most systems translate a whole scan directly into text. Radiologists instead inspect individual Regions of Interest (RoIs) before writing a conclusion. To support this region-centred approach, the authors release VietPET-RoI, a Vietnamese dataset in which every finding mentioned in a report is linked to a 3D bounding box and a structured set of clinical attributes. They also present HiRRA, a vision-language model that keeps CT and PET features in separate streams before merging them. HiRRA then uses graph-based relational modules to model how RoIs and their attributes depend on each other. For evaluation, they propose RoI Coverage and RoI Quality Index, two clinically oriented measures computed with LLM assistance. HiRRA outperforms the strongest baseline, M3D-LaMed, on both text-overlap and clinical scores. The work offers a grounded, more interpretable and less hallucination-prone route to PET/CT reporting in a low-resource language.
Key points
- VietPET-RoI data: 200 cancer patients from one Vietnamese hospital, covering six common cancer types scanned in 2017–2019. Each scan is standardised to 313 slices and split into head-neck, chest and abdomen-pelvis segments with a 15-slice overlap. This yields 600 image–report pairs and 1,960 manually annotated RoIs.
- Annotation process: Eight nuclear medicine physicians used 3DSlicer to mark each RoI and fill a template with ten attributes, including size, SUVmax, density, FDG uptake, and top-3 diagnoses and follow-up tests. Senior physicians verified all annotations.
- Main results: Compared with M3D-LaMed, HiRRA improves BLEU-4 by 19.7% and ROUGE-L by 4.7%. It also gains 15.5% and 45.8% on the two clinical metrics.
- Fusion ablation: Combining CT and PET reaches 36.1 BLEU-4, compared with 31.3 for CT alone and 33.6 for PET alone.
- Limitations: The data come from a single institution, which may introduce demographic bias. Annotation is costly at about 15–30 minutes per case, and the model has high compute requirements. The dataset is released for non-commercial research only.
Institutions
Fields, topics and concepts
📚 Shelves 7The field of science this work belongs to (OpenAlex fields).Computer Science · 18,614 worksArtificial Intelligence · 17,965 worksArts and Humanities · 17,450 worksLanguage and Linguistics · 17,296 worksComputer Vision and Pattern Recognition · 3,486 worksMedicine · 275 worksHealth Informatics · 214 works
Cite
Cite as Cong Huy Nguyen, Son Dinh Nguyen, Guanlin Li, Tuan Dung Nguyen, Aditya Narayan Sankaran, Mai Huy Thong, Thanh Trung Nguyen, Mai Hong Son, Reza Farahbakhsh, Phi Le Nguyen and Noel Crespi. 2026. Region-Grounded Report Generation for 3D Medical Imaging: A Fine-Grained Dataset and Graph-Enhanced Framework. Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers).
@inproceedings{nguyen2026region,
title = {{Region-Grounded Report Generation for 3D Medical Imaging: A Fine-Grained Dataset and Graph-Enhanced Framework}},
author = {Cong Huy Nguyen, Son Dinh Nguyen, Guanlin Li, Tuan Dung Nguyen, Aditya Narayan Sankaran, Mai Huy Thong, Thanh Trung Nguyen, Mai Hong Son, Reza Farahbakhsh, Phi {Le Nguyen} and Noel Crespi},
booktitle = {Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)},
year = {2026},
doi = {10.18653/v1/2026.acl-long.903},
url = {https://doi.org/10.18653/v1/2026.acl-long.903}
}References
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