Research: Ferumoxytol, an FDA-approved superparamagnetic iron oxide nanoparticle (SPION), stands as a promising solution for iron replacement therapy in individuals with anemia due to renal insufficiency. Possessing a relatively large particle size of approximately 30 nm, ferumoxytol exhibits an elimination plasma half-life of approximately 14 hours within the human body. This characteristic extends the acquisition time window and facilitates high-resolution steady-state imaging through the application of a free-breathing technique. Compared to the conventional Gadolinium-based contrast agents, ferumoxytol has a stronger T1, T2, T2* shortening effect and produces hyperintense blood signal on T1-weighted images. By acquiring the images at the shortest echo time possible, we suppress the T2* effect and generate exceptionally heavy T1-weighting, enabling quantitative assessment on the blood volume in the regions of interest. Here we introduce a novel technique that combines ferumoxytol with Ultrashort Time-to-Echo (UTE) sequences, known as Quantitative UTE Contrast Enhanced (QUTE-CE) MRI. We demonstrate the generation of a global map depicting quantitative cerebral blood volume in rat models and explore its changes in response to CO2 challenges. Subsequently, we transition this technique to human cerebral imaging, where we produce high-contrast angiograms of the brain. Finally, we showcase its application in patients with Chronic Kidney Disease, highlighting its utility for blood volume quantification and renal mass assessment.