Original title: RARF: Region-Aware Rectified Flows for 3D Brain MRI Inpainting
Tomas Guija-Valiente, Blanca Rodriguez-Gonzalez, Norberto Malpica, Angel Torrado-Carvajal · September 2026
Diseased brain tissue can disrupt automated medical scans. Researchers want to fill these damaged areas with realistic healthy tissue, a process called inpaintingFilling in missing or corrupted parts of an image.. To solve this, the authors created RARF. Instead of changing the entire three-dimensional scan, RARF leaves the healthy areas untouched to preserve the patient's unique anatomy. It only works inside the missing zone, which it initially fills with random Gaussian noise. A neural network learns to gradually turn that noise into realistic brain tissue over time using learned trajectories called rectified flows. Finally, the system merges the newly created tissue with the original, unchanged brain. Tests following the BraTS protocol showed that RARF generates competitive reconstructions while keeping the anatomy consistent with the rest of the brain.
Imagine you have a jigsaw puzzle with several pieces missing, and you want to complete the picture without seeing the box cover. You need to guess what the missing pieces look like based only on the edges and patterns of the surrounding pieces. In this paper, the system does something similar for brain scans: it takes a scan with gaps from disease and fills those gaps with healthy tissue that fits seamlessly with the existing parts.
For doctors and AI systems analyzing brain scans, this could make it easier to study healthy tissue patterns in patients with brain tumors. It provides complete images even when parts are damaged, potentially improving diagnosis and treatment planning.
The abstract doesn't state specific limitations, but it indicates the approach is evaluated under the BraTS protocol for 3D brain MRI. Its performance on other types of medical images or different anatomies is not established.
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RARF: Region-Aware Rectified Flows for 3D Brain MRI Inpainting — Tomas Guija-Valiente, Blanca Rodriguez-Gonzalez, Norberto Malpica et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.