Abstract
OBJECTIVE: This study aimed to investigate the ability of amide proton transfer (APT) imaging to assess the function of transplanted kidneys. METHODS: Between October 2023 and July 2024, a total of 44 renal allograft recipients were recruited prospectively, who underwent renal APT imaging with a 3.0 T system 2-3 weeks after transplantation. Recipients were divided into two groups according to the estimated glomerular filtration rate (eGFR): group A, eGFR < 60 mL/min/1.73 m(2); and group B, eGFR ≥60 mL/min/1.73 m(2). The relationships between cortical and medullary APT values and allograft function were assessed using the Spearman's correlation coefficient. The paired sample t-test was used to compare cortical and medullary APT values. APT values in groups A and B were compared using the Student's t-test or Mann-Whitney U-test. Receiver operating characteristic curves were generated to assess the ability of cortical and medullary APT values to diagnose impaired allograft function. RESULTS: Two physicians calculated APT values independently and with good agreement, as indicated by an intraclass correlation coefficient > 0.75. The renal cortical and medullary APT values in group A (2.61% ± 0.51% and 2.11% ± 0.37%, respectively) were significantly higher than those in group B (1.77% ± 0.13% and 1.79% ± 0.29%, respectively) (P < 0.05). APT values in the renal cortex and medulla were negatively correlated with eGFR (r = -0.8551 and r = -0.5163, respectively; P < 0.01). In group A, cortical APT values were higher than medullary APT values (P < 0.05). Cortical and medullary APT values demonstrated a good ability to diagnose impaired renal allograft function. In group A, mean cortical APT values were higher in patients whose renal function did not recover (3.10% ± 0.54%) than in those with stable allograft function 6 months after transplantation (2.50% ± 0.44%) (P < 0.05). CONCLUSION: APT imaging is a promising technique for non-invasive functional assessment of renal allografts.