Multi-site, in vivo MRI dataset of brain diffusivity measures before and after harmonization, and atrophy measures following controlled cortical impact in male and female adult rats

Traumatic brain injury (TBI) research faces persistent challenges in data comparability and reproducibility, particularly in multi-center preclinical studies. Structured, interoperable datasets are essential to identify robust imaging biomarkers and validate cross-site findings. This dataset comprises 343 diffusion-weighted MRI scans from 186 male and female Sprague Dawley rats subjected to controlled cortical impact (CCI) or sham procedures at four independent research sites. Imaging was performed at 3 and 30 days post-injury using harmonized acquisition protocols and field strengths ranging from 7T to 11.7T. A standardized processing pipeline generated scalar diffusion maps (FA, MD, AD, and RD), anatomical templates, and voxel-wise <i>z</i>-score-based indices of injury. Both unharmonized and harmonized versions of the dataset are provided. Harmonization was performed using NeuroCombat for scalar volumes and multi-site template registration for voxel-level alignment. The dataset supports investigations into sex, post-injury timepoint, and injury effects in experimental TBI and provides a foundation for testing image harmonization methods, developing quantification tools for automated assessment of injury, and training machine learning models. The dataset is published in the FAIR² framework, with machine-actionable metadata, responsible AI indicators, and structured documentation to support ethical, reproducible, and AI-ready reuse.