Table 3.
Comparison of quantitative cartilage measures between manual and U-Net-based automated segmentations determined from n = 21 knees from the test set
| Manual | U-Net | Manual vs. U-Net | ||||||
|---|---|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | Diff (%) | P | r | ||
| Cartilage thickness (mm) | ||||||||
| MFTC | corFLASH | 3.6 | 0.4 | 3.8 | 0.4 | 5.1 | < 0.001 | 0.96 |
| sagDESS | 3.4 | 0.5 | 3.5 | 0.4 | 2.8 | 0.019 | 0.95 | |
| MT | corFLASH | 1.7 | 0.2 | 1.8 | 0.2 | 4.7 | < 0.001 | 0.97 |
| sagDESS | 1.6 | 0.2 | 1.7 | 0.2 | 3.7 | 0.006 | 0.93 | |
| cMF | corFLASH | 1.8 | 0.3 | 1.9 | 0.2 | 5.5 | < 0.001 | 0.93 |
| sagDESS | 1.8 | 0.3 | 1.8 | 0.2 | 1.9 | 0.224 | 0.92 | |
| LFTC | corFLASH | 3.8 | 0.5 | 4.0 | 0.5 | 4.4 | < 0.001 | 0.98 |
| sagDESS | 3.8 | 0.5 | 3.9 | 0.5 | 4.1 | < 0.001 | 0.97 | |
| LT | corFLASH | 2.1 | 0.3 | 2.2 | 0.3 | 4.6 | < 0.001 | 0.97 |
| sagDESS | 2.0 | 0.3 | 2.1 | 0.3 | 3.5 | < 0.001 | 0.97 | |
| cLF | corFLASH | 1.7 | 0.3 | 1.8 | 0.2 | 4.2 | < 0.001 | 0.97 |
| sagDESS | 1.7 | 0.3 | 1.8 | 0.2 | 4.8 | 0.001 | 0.96 | |
| Cartilage volume (mm3) | ||||||||
| MFTC | corFLASH | 2947 | 829 | 3218 | 797 | 9.2 | < 0.001 | 0.99 |
| sagDESS | 2801 | 794 | 2912 | 737 | 4.0 | 0.005 | 0.98 | |
| MT | corFLASH | 1945 | 570 | 2120 | 534 | 9.0 | < 0.001 | 0.99 |
| sagDESS | 1703 | 532 | 1848 | 496 | 8.5 | < 0.001 | 0.98 | |
| cMF | corFLASH | 1003 | 279 | 1099 | 277 | 9.6 | < 0.001 | 0.96 |
| sagDESS | 1098 | 285 | 1064 | 256 | -3.1 | 0.154 | 0.93 | |
| LFTC | corFLASH | 3123 | 859 | 3421 | 904 | 9.6 | < 0.001 | 0.99 |
| sagDESS | 3291 | 928 | 3433 | 872 | 4.3 | < 0.001 | 0.99 | |
| LT | corFLASH | 2083 | 589 | 2294 | 622 | 10.1 | < 0.001 | 0.99 |
| sagDESS | 2144 | 646 | 2295 | 618 | 7.0 | < 0.001 | 0.99 | |
| cLF | corFLASH | 1039 | 298 | 1128 | 302 | 8.5 | < 0.001 | 0.98 |
| sagDESS | 1147 | 311 | 1138 | 264 | -0.8 | 0.623 | 0.97 | |
| Total area of subchondral bone (cm2) | ||||||||
| MFTC | corFLASH | 16.1 | 2.8 | 16.3 | 2.8 | 1.5 | 0.040 | 0.98 |
| sagDESS | 15.3 | 2.7 | 15.7 | 2.7 | 2.5 | < 0.001 | 0.99 | |
| MT | corFLASH | 11.0 | 1.9 | 11.2 | 1.8 | 1.7 | 0.027 | 0.98 |
| sagDESS | 10.0 | 1.7 | 10.4 | 1.8 | 3.8 | < 0.001 | 0.99 | |
| cMF | corFLASH | 5.1 | 1.0 | 5.2 | 1.0 | 1.1 | 0.395 | 0.96 |
| sagDESS | 5.3 | 1.0 | 5.3 | 1.0 | 0.0 | 0.999 | 0.95 | |
| LFTC | corFLASH | 15.2 | 2.6 | 15.5 | 2.7 | 1.9 | 0.015 | 0.98 |
| sagDESS | 15.6 | 2.8 | 15.8 | 2.7 | 1.6 | 0.024 | 0.99 | |
| LT | corFLASH | 9.4 | 1.6 | 9.7 | 1.7 | 2.9 | 0.010 | 0.96 |
| sagDESS | 9.9 | 1.7 | 10.1 | 1.7 | 2.2 | 0.018 | 0.98 | |
| cLF | corFLASH | 5.8 | 1.1 | 5.8 | 1.1 | 0.1 | 0.904 | 0.98 |
| sagDESS | 5.7 | 1.1 | 5.7 | 1.0 | 0.5 | 0.485 | 0.99 | |
Quantitative measures were calculated from coronal FLASH (corFLASH) and sagittal DESS (sagDESS) MRI acquired at the OAI baseline visit
MFTC/LFTC medial/lateral femorotibial compartment, MT/LT medial/lateral tibia, cMF/cLF central medial/lateral femoral condyle, P p value from paired t-tests, r Pearson correlation coefficient