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

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.