BTReport: A Framework for Brain Tumor Radiology Report Generation with Clinically Relevant Features
Organizations: University of Washington · University of Washington School of Medicine · Microsoft Health AI · Johns Hopkins School of Medicine
Abstract
Recent advances in radiology report generation (RRG) have been driven by large paired image-text datasets; however, progress in neuro-oncology has been limited due to a lack of open paired image-report datasets. Here, we introduce BTReport, an open-source framework for brain tumor RRG that constructs natural language radiology reports using deterministically extracted imaging features. Unlike existing approaches that rely on large general-purpose or fine-tuned vision-language models for both image interpretation and report composition, BTReport performs deterministic feature extraction for image analysis and uses large language models only for syntactic structuring and narrative formatting. By separating RRG into a deterministic feature extraction step and a report generation step, the generated reports are completely interpretable and less prone to hallucinations. We show that the features used for report generation are predictive of key clinical outcomes, including survival and IDH mutation status, and reports generated by BTReport are more closely aligned with reference clinical reports than existing baselines for RRG. Finally, we introduce BTReport-BraTS, a companion dataset that augments BraTS imaging with synthetically generated radiology reports produced with BTReport. Code for this project can be found at https://github.com/KurtLabUW/BTReport.
Figures & tables
| Total tumor volume (mL) | Ventricular Invasion | Level of max MLS | ||||||
| 3D Lesion Sizes (cm) | Side of Tumor Epicenter | Max MLS (mm) + L/R | ||||||
| Proportion of Necrosis | Enhancement Quality | Edema crosses midline | ||||||
| Number of lesions | Enhancement thickness | ET Crosses midline | ||||||
| Proportion of Enhancing | Multiple satellites present | Asymmetrical Ventricles | ||||||
| Proportion of Edema | Multifocal or Multicentric | Enlarged Ventricles | ||||||
| Cortical involvement | Deep WM invasion |
| Accuracy | MAE | |||||
| Method | Cortical | Side of | Ventricular | Midline shift | Number of | Tumor volume |
| involvement | tumor epicenter | effacement | (mm) | lesions | (cm 3 ) | |
| BTReport (V1) | 0.79 | 1.00 | 0.56 | 1.26 2.60 | 1.48 2.63 | 1.80 3.95 |
| BTReport (V2) | 0.80 | 1.00 | 0.52 | 1.21 2.55 | 0.41 1.69 | 2.00 5.16 |
| V1: DeepMedic Kamnitsas et al. (2017) segmentations V2: Faking It Ferreira et al. (2024) segmentations | ||||||
| Framework | BLEU-1 | BLEU-2 | ROUGE-1 | ROUGE-2 |
| BTReport (gpt-oss:120B, V1) † | 0.236 0.068 | 0.124 0.044 | 0.360 0.078 | 0.109 0.038 |
| BTReport (gpt-oss:120B, V2) † | 0.244 0.070 | 0.132 0.044 | 0.371 0.078 | 0.115 0.040 |
| BTReport (LLaMA3:70B, V1) † | 0.248 0.078 | 0.136 0.052 | 0.362 0.080 | 0.115 0.043 |
| AutoRG-Brain Lei et al. (2024) | 0.158 0.072 | 0.080 0.042 | 0.268 0.060 | 0.070 0.032 |
| Seg-to-Exp Valerio et al. (2025) | 0.085 0.039 | 0.035 0.018 | 0.163 0.055 | 0.023 0.013 |
| V1: DeepMedic Kamnitsas et al. (2017) segmentations V2: Faking It Ferreira et al. (2024) segmentations | ||||
| TBFact (DeepSeek-R1) | BERTScore | RaTEScore | ||||
| Framework | Score | Prec. | Recall | F1 | ||
| BTReport (gpt-oss:120B, V1) † | 0.313 0.145 | 0.345 0.155 | 0.325 0.163 | 0.313 0.145 | 0.447 0.060 | 0.568 0.057 |
| BTReport (gpt-oss:120B, V2) † | 0.353 0.151 | 0.412 0.146 | 0.349 0.162 | 0.359 0.145 | 0.453 0.055 | 0.577 0.054 |
| BTReport (LLaMA3:70B, V1) † | 0.295 0.130 | 0.377 0.168 | 0.274 0.136 | 0.295 0.130 | 0.433 0.062 | 0.567 0.061 |
| AutoRG-Brain Lei et al. (2024) | 0.072 0.123 | 0.282 0.155 | 0.186 0.137 | 0.196 0.130 | 0.327 0.047 | 0.477 0.053 |
| Seg-to-Exp Valerio et al. (2025) | 0.014 0.047 | 0.131 0.121 | 0.147 0.108 | 0.098 0.089 | 0.156 0.042 | 0.409 0.039 |
Appendix figures & tables7 assets
Supplementary material from the paper’s appendix.
Appendix
| Cluster Description | Frequency | Two Example Sentences in this cluster |
| Lateral ventricle effacement/asymmetry; possible… | 50 | “The lateral ventricles are symmetric.” , “The lateral ventricles are symmetric” |
| Midline shift presence and magnitude.… | 27 | “There is a 2 mm left midline shift” , “There is a susceptibility millimeters rightward midline shift.” |
| Cisterns appear normal, no obstruction. | 19 | “The basal cisterns are patent.” , “The basal cisterns are patent” |
| Peritumoral/Vasogenic edema present. *(This… | 18 | “There is mild-to-moderate associated edema” , “The first mass has associated surrounding vasogenic edema” |
| Lesion size and measurements reported. | 16 | “The lesion measures 4.0 x 3.5 cm” , “The lesion measures 3.9 x 2.0 x 2.1 cm.” |
| No acute intracranial hemorrhage or infarct. | 15 | “There is no acute infarct” , “No acute infarct is seen” |
| Question | Response Options (single-select) | Conditional Follow-Up (select all that apply) |
| Hallucinations | None; Minor; Major | Shown if Minor/Major selected: |
| Type of hallucination(s) observed? | ||
| • Incorrect anatomical location of tumor • Incorrect tumor characteristics (e.g., size, laterality, enhancement) • Incorrect clinical implication • Fabricated finding • Other (free text: Other hallucination details ) | ||
| Missing Features | No; Some; Many | Shown if Some/Many selected: |
| Most impactful missing element(s)? | ||
| • Tumor size/extent • Enhancement characteristics • Edema/mass effect • Midline shift • Multifocality • Invasion/eloquent cortex • Other ( free text ) |
| Question | Criteria | 1 | 2 | 3 | 4 |
| Would this report support or hinder your clinical decision making (e.g., treatment planning, surgical consultation, oncology consultation)? | Decision Support | Strongly hinders | Slightly hinders | Slightly supports | Strongly supports |
| Assess the clinical accuracy of this report. | Clinical Accuracy | Clinically inaccurate | Partially inaccurate | Mostly accurate | Fully accurate |
| To what extent does this report omit clinically relevant findings? | Clinical Omission | Major clinically relevant omissions | Several clinically relevant omissions | Minor clinically relevant omissions | No clinically relevant omissions |
| To what extent does this report differ or align with the clinical structure of a standard neuroradiology report? | Clinical Structure | Substantially differs from typical clinical reporting | Somewhat differs from typical clinical reporting | Somewhat consistent with typical clinical reporting | Highly consistent with typical clinical reporting |