TABLE 3.
Overview of Repeatability Measures for the Multiparametric Scan Protocol
| Baseline | Follow up | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Sequence | Parameter | Unit | N | Mean (SD) | Mean (SD) | Bias (%) | CoV (%) | RC (%) | ICC |
| Relaxometry | |||||||||
| T1 map | T1 cortex | ms | 28 | 1526 (54) | 1440 (84) | −5.8 | 5.1 | 14 (9–18) | 0.32 (−0.11–0.71) |
| T1 medulla | ms | 28 | 1870 (61) | 1820 (66) | −2.7 | 2.8 | 7.8 (5.2–10.2) | 0.48 (0.00–0.75) | |
| T2 map | T2 parenchyma | ms | 35 | 113 (8.2) | 114 (7.6) | 0.8 | 2.9 | 8.2 (5.7–10.7) | 0.82 (0.67–0.90) |
| R2* map | R2* cortex | 1/s | 34 | 19.3 (2.1) | 19.0 (1.9) | −1.6 | 6.1 | 18 (13–24) | 0.58 (0.31–0.77) |
| R2* medulla | 1/s | 34 | 26.2 (2.7) | 25.6 (2.2) | −2.0 | 5.8 | 16 (11–22) | 0.62 (0.36–0.79) | |
| DTI and IVIM | |||||||||
| DTI | MD cortex | mm2/s | 36 | 2.3 (0.2) | 2.3 (0.2) | −0.3 | 3.7 | 10 (7–13) | 0.74 (0.55–0.86) |
| MD medulla | mm2/s | 36 | 2.4 (0.1) | 2.4 (0.1) | 0.8 | 2.8 | 7.7 (5.4–10) | 0.76 (0.59–0.87) | |
| FA cortex | — | 36 | 0.31 (0.03) | 0.31 (0.04) | −0.4 | 6.7 | 19 (13–25) | 0.63 (0.38–0.79) | |
| FA medulla | — | 36 | 0.40 (0.04) | 0.40 (0.04) | −0.5 | 5.2 | 15 (10–19) | 0.74 (0.55–0.86) | |
| IVIM | D cortex | mm2/s | 36 | 2.1 (0.1) | 2.1 (0.2) | 1.0 | 6.7 | 18 (13–24) | 0.24 (−0.10–0.52) |
| D medulla | mm2/s | 36 | 1.9 (0.1) | 1.9 (0.2) | −0.5 | 7.2 | 20 (14–26) | 0.23 (−0.11–0.52) | |
| FP cortex | % | 36 | 10 (3) | 10 (3) | −4.0 | 24 | 87 (61–113) | −0.01 (−0.34–0.32) | |
| FP medulla | % | 36 | 13 (3) | 12 (3) | −5.2 | 18 | 56 (39–73) | 0.35 (0.03–0.61) | |
| Perfusion and GFR | |||||||||
| FAIR | Cortical perfusion | mL/100 mL/min | 28 | 340 (51) | 350 (49) | 2.8 | 10 | 29 (19–39) | 0.47 (0.13–0.72) |
| ATT | s | 28 | 0.50 (0.13) | 0.50 (0.14) | −1.3 | 12 | 34 (22–46) | 0.80 (0.62–0.90) | |
| DCE | Parenchymal perfusion | mL/100 mL/min | 30 | 443 (110) | 435 (132) | −1.8 | 16 | 44 (30–59) | 0.67 (0.41–0.83) |
| MRT | s | 30 | 5.1 (1.0) | 5.2 (0.9) | 3.1 | 12 | 32 (21–43) | 0.50 (0.30–0.78) | |
| skGFR | mL/min | 30 | 45 (10) | 44 (9) | −3.5 | 13 | 36 (24–47) | 0.66 (0.40–0.82) | |
| PC | RBF per artery | mL/min | 37* | 388 (147) | 381 (141) | −2.0 | 13 | 37 (26–47) | 0.88 (0.77–0.93) |
| Fat quantification | |||||||||
| Dixon | Fat fraction sinus | — | 38 | 0.41 (0.12) | 0.41 (0.12) | −0.2 | 9.2 | 19 (23–24) | 0.95 (0.90–0.97) |
| Fat volume sinus | mL | 38 | 16.3 (8.4) | 15.8 (8.3) | −3.2 | 9.5 | 20 (24–25) | 0.98 (0.96–0.99) | |
In Table S1 in the Supplemental Material, CoV values are compared to literature values.
N: number of kidneys; SD: standard deviation; CoV: within‐subject coefficient of variation; ICC: intraclass correlation coefficient (two‐way mixed effects, absolute agreement, single measurement); DTI: diffusion tensor imaging; MD: mean diffusivity; FA: fractional anisotropy; IVIM: intravoxel incoherent motion; D: diffusion coefficient; Fp: perfusion fraction; FAIR: flow alternating inversion recovery; ATT: arterial transit time; DCE: dynamic contrast enhanced MRI; skGFR: single kidney glomerular filtration rate; MRT: mean residence time; PC: phase contrast; RBF: renal blood flow; *number of arteries.