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.