Functional Sodium MRI Helps to Measure Corticomedullary Sodium Content in Superior and Inferior Function of Transplant Kidney

Motivation: This study is motivated by tools to explore transplanted kidney tubular function is still not well developed. Goal(s): Assessing the performance of sodium cortico-medullary gradient (CMG) in evaluating the ability of the transplanted kidney to concentrate urine, transplant kidney function and biopsy scoring. Approach: CMG was estimated by measuring the medulla-to-cortex signal ratio from sodium MRI. Pearson or spearman correlation was performed between CMG and urine specific gravity, eGFR, and the biopsy scoring. Results: The medulla-to-cortex ratio was significantly correlated with mean urine specific gravity and eGFR, and also showed significant correlation with t - IFTA of the Banff score. Impact: Sodium MRI accurately depicted CMG in transplanted kidney that correlated with ability of concentrate urine. CMG was related to eGFR and t-IFTA. The findings will contribute to develop non-invasive imaging method to evaluation tubular function and disease of transplanted kidney.