Multiparametric MRI Evaluation of Renal Functional Reserve in Response to Oral Protein Loading

Motivation: Renal stress-testing evaluates renal functional reserve (RFR) after protein loading. While prior work has used renal stress-testing to evaluate kidney function, RFR remains unexplored using multiparametric-MRI. Goal(s): We aimed to evaluate the feasibility of MRI renal stress-testing and characterize the response to protein load in healthy individuals. Approach: Eight healthy subjects (33±25years, 5 females) underwent multiparametric MRI after animal- and plant-based protein loads. We measured renal blood flow(RBF), T2*, T1, and kidney volumes. Results: RBF increased significantly 30-minutes post-protein load and remained elevated for 120-minutes, with no changes in T2*, T1, or renal volume, suggesting an increase in GFR with balanced oxygen utilization. Impact: This non-invasive MRI renal stress test provides spatially resolved assessment of functional renal reserve, opening new possibilities for imaging diagnostic evaluations of the kidney. Future work should explore renal reserve evaluation in clinical and subclinical kidney disease populations.