Reproducibility of native T1 mapping for renal tissue characterization at 3T

Background: Advanced renal disease is characterized by adverse changes in renal structure; however, noninvasive techniques to diagnose and monitor these changes are currently lacking. Purpose: To evaluate the reproducibility of native T1 mapping for renal tissue characterization. Study Type: Reproducibility study. Population: Fifteen healthy volunteers (mean age 31 years, range 19–63 years), and 11 patients with diabetic nephropathy (mean age 57 years, range 51–69 years). Field Strength/Sequence: 3T, modified Look–Locker imaging (MOLLI) 5(3)3. Assessment: Intra- and interexamination reproducibility of voxel-based T1 relaxation times of renal cortex and medulla was assessed in healthy human volunteers and diabetic nephropathy patients. Statistical Tests: Reproducibility was evaluated using Bland–Altman and intraclass correlation coefficients (ICCs). Results: Intra- and interexamination reproducibility of renal native T1 mapping showed good–strong ICCs (0.83–0.89) for renal cortex and medulla, and moderate–good ICCs (0.62–0.81) for cortex–medulla ratio in both healthy volunteers and diabetic nephropathy patients. Intra- and interexamination limits of agreement were respectively (–124 msec, + 82 msec) and (–134 msec, + 98 msec) for renal cortex and (–138 msec, + 107 msec) and (–118 msec, + 151 msec) for medulla. Overall T1 values for renal cortex (P = 0.277) and medulla (P = 0.973) were not significantly different between healthy volunteers and diabetic nephropathy patients, in contrast to the cortex–medulla ratio (P = 0.003). Data Conclusion: Renal native T1 mapping is a technique with good–strong intra- and examination reproducibility in both healthy volunteers and diabetic nephropathy patients. Level of Evidence: 3. Technical Efficacy: Stage 1. J. Magn. Reson. Imaging 2019;49:588–596.