Table 4.
Descriptive statistics and predictive properties (ROC AUC) of univariate imaging markers to distinguish between DKD subjects (stages G3‒G5) and HVs, including respective specificity and sensitivity for Youden cut-off values
| HVs | DKD (stages G3‒G5) | Prediction performance | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Variable | n | Mean (SD) | n | Mean (SD) | ROC AUC | Cut-off | Sensitivity | Specificity | *P-value |
| Kidney haemodynamics | |||||||||
| MAF (mL/min/1.73 m2) | 20 | 993 (126) | 36 | 538 (161) | 0.99 | <803 | 0.94 | 1.00 | .04 |
| PSV (cm/s) | 20 | 54.3 (8.28) | 36 | 50.5 (15.0) | 0.62 | <48.3 | 0.53 | 0.85 | .30 |
| EDV (cm/s) | 20 | 17.0 (3.9) | 36 | 8.75 (3.6) | 0.94 | <12.6 | 0.89 | 0.90 | .0005 |
| RARI | 20 | 0.68 (0.06) | 36 | 0.82 (0.06) | 0.94 | >0.73 | 0.94 | 0.85 | .0001 |
| ASL perfusion cortex (mL/min/100 g) | 20 | 164 (36.8) | 35 | 81.1 (40.7) | 0.93 | <125 | 0.86 | 0.90 | .0001 |
| Global perfusion (mL/min/100 g) | 20 | 458 (54) | 36 | 311 (83) | 0.94 | <380 | 0.81 | 0.95 | .001 |
| Kidney macrostructure | |||||||||
| Kidney volume (mL/1.73 m2) | 20 | 218 (26) | 36 | 176 (38) | 0.83 | <206 | 0.83 | 0.75 | .0008 |
| Kidney oxygenation | |||||||||
| BOLD R2* cortex (per s) | 20 | 17.3 (1.4) | 33 | 17.1 (1.4) | 0.52 | <16.6 | 0.36 | 0.80 | .53 |
| BOLD R2* medulla (per s) | 20 | 26.0 (2.3) | 33 | 23.5 (3.7) | 0.75 | <22.6 | 0.48 | 1.00 | .002 |
| Kidney microstructure | |||||||||
| ADC cortex (10–3 mm2/s) | 20 | 2.52 (0.19) | 34 | 2.31 (0.21) | 0.79 | <2.37 | 0.71 | 0.85 | .002 |
| ADC medulla (10–3 mm2/s) | 20 | 2.33 (0.18) | 34 | 2.19 (0.24) | 0.71 | <2.21 | 0.65 | 0.75 | .03 |
| R1 cortex (per s) | 20 | 0.72 (0.03) | 36 | 0.63 (0.04) | 0.97 | <0.69 | 0.94 | 0.90 | .001 |
| R1 medulla (per s) | 20 | 0.55 (0.02) | 36 | 0.55 (0.02) | 0.58 | <0.55 | 0.56 | 0.65 | .34 |
| IVIM D cortex (10−3 mm2/s) | 20 | 2.14 (0.24) | 34 | 1.91 (0.26) | 0.75 | <1.98 | 0.65 | 0.80 | .006 |
| IVIM D medulla (10−3 mm2/s) | 20 | 2.04 (0.27) | 34 | 1.85 (0.20) | 0.72 | <2.05 | 0.91 | 0.45 | .01 |
| IVIM D* cortex (10−3 mm2/s) | 19 | 56 (73.3) | 32 | 98 (351) | 0.48 | >19.4 | 0.72 | 0.37 | .62 |
| IVIM D* medulla (10−3 mm2/s) | 19 | 198 (459) | 31 | 190 (768) | 0.55 | <165 | 0.90 | 0.26 | .96 |
| IVIM f cortex (%) | 19 | 13.5 (5.7) | 32 | 15.2 (5.7) | 0.60 | >15 | 0.53 | 0.74 | .32 |
| IVIM f medulla (%) | 19 | 12.3 (5.1) | 31 | 14.5 (5.7) | 0.62 | >13.5 | 0.61 | 0.74 | .17 |
| MTR cortex (%) | 20 | 23 (1.9) | 36 | 21.8 (2.2) | 0.66 | <21.7 | 0.56 | 0.80 | .06 |
| MTR medulla (%) | 20 | 24.5 (2.13) | 36 | 23.7 (2.43) | 0.57 | <22.5 | 0.42 | 0.85 | .27 |
| Biochemistry | |||||||||
| eGFR (mL/min/1.73 m2) | 20 | 76.4 (7.76) | 36 | 34.9 (13.8) | 0.99 | <60 | 0.97 | 1.00 | .02 |
| UACR (mg/mmol) | 20 | 1.17 (0.54) | 36 | 67 (83.3) | 1.00 | >1.9 | 1.00 | 1.00 | .02 |
*P-value of OR = 1 for the variable (Wald test) in the model. Note that P-values are inappropriate in cases when there is complete (or quasi-complete) separation of data points, i.e. when sensitivity and specificity = 1 (or close to 1).