Failure in the blood brain barrier (BBB) lies at the foundation of small vessel disease that is precursor to neurodegenerative diseases. There are multiple risk factors leading to increased permeability in the BBB; one prevalent risk factor is repetitive mild TBI. Imaging the subtle changes in BBB permeability is not possible with standard imaging protocols. With quantitative ultra-short time-to-echo, contrast-enhanced (QUTE-CE) MRI, using the superparamagnetic iron oxide nanoparticle ferumoxytol, we can image changes in BBB permeability following rmTBI. With this novel methodology we can measure the immediate effects of rmTBI on changes in BBB permeability across the entire rat brain.