Background
Methods
Study design
Participants
Sample size, randomisation and blinding
Interventions
MRI protocol
Image analysis
Variable name | Abbreviation | Definition |
---|---|---|
Highly Perfused Voxels | Nvoxel | The number of voxels with “plateau” or “washout” enhancement patterns, i.e. the highest perfused voxels, the most perfused tissue. |
Proportion of Highly Perfused Voxels (%) | Nvoxel% | The proportion of highly perfused voxels reaching either a “plateau” or “washout” enhancement pattern (Nvoxel) in percentage of the total number of voxels within the VOI. |
Initial Rate of Enhancement | IRE | The upslope on the Time intensity curve measured as the mean relative increase in signal intensity per second from enhancement onset until ME is reached(%/s). A surrogate of the degree of perfusion. |
Maximal Enhancement | ME | The highest mean signal intensity value relative to the baseline intensity. A surrogate of the degree of perfusion. |
Initial Rate of Enhancement Composite Score | IRExNvoxel | The mean relative increase in signal intensity per second (%/s) (IRE) multiplied by the number of highly perfused voxels (Nvoxel). The variable becomes a composite parameter reflecting both the volume (voxels) and the degree of perfusion. |
Initial Rate of Enhancement Index | IRExNvoxel% | The mean relative increase in signal intensity per second (%/s) (IRE) multiplied by the proportion of highly perfused voxels (Nvoxel%). |
Maximal Enhancement Composite Score | MExNvoxel | The highest mean signal intensity value relative to the baseline intensity (ME) multiplied by the number Highly Perfused Voxels. The variable becomes a composite parameter reflecting both the volume (voxels) and the degree of perfusion. |
Maximal Enhancement index | MExNvoxel% | The highest mean signal intensity value relative to the baseline intensity (ME) multiplied by the Proportion of Highly Perfused Voxels. |
Outcomes
Statistical methods
Ancillary analyses
Results
Exercise therapy group | Control group | |||
---|---|---|---|---|
Randomised (n = 31) | Per-protocol (n = 16) | Randomised (n = 29) | Per-protocol (n = 17) | |
Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | |
Demographic Characteristics | ||||
Age (years) | 65.9 (8.5) | 67.2 (8.2) | 61.3 (7.1) | 60.6 (7.2) |
Female, no (%) | 27 (87) | 14 (87.5) | 21 (71) | 12 (70.6) |
Height (m) | 1.69 (0.08) | 1.67 (0.07) | 1.72 (0.09) | 1.72 (0.11) |
Weight (kg) | 81.9 (14.1) | 77.3 (8.3) | 83.3 (15.0) | 85.8 (14.2) |
BMI (kg/m2) | 28.7 (4.2) | 27.7 (3.4) | 28.1 (4.5) | 29.0 (4.0) |
KOOS | ||||
Pain | 56.5 (14.8) | 52.8 (18.1) | 63.3 (12.4) | 61.3 (9.8) |
Symptoms | 58.3 (16.8) | 57.4 (18.2) | 65.5 (19.5) | 63.9 (17.8) |
Function in Daily Living | 65.0 (14.0) | 61.9 (17.3) | 74.2 (13.9) | 76.3 (10.9) |
Knee-Related Quality of Life | 27.6 (19.2) | 37.9 (15.6) | 34.7 (20.9) | 44.1 (16.8) |
Function in Sports and Recreation | 37.1 (14.2) | 25.0 (16.0) | 44.2 (14.4) | 37.4 (23.0) |
DCE-MRI Perfusion variables | ||||
Total Muscle VOI | ||||
Nvoxel% | – | 56.1 (15.7) | – | 57.7(14.7) |
IRExNvoxel | – | 334.0 (171.5) | – | 386.7 (230.2) |
IRExNvoxel% | – | 0.30 (0.15) | – | 0.18 (0.07) |
MExNvoxel | – | 81,491.0 (26,054.0) | – | 91,236.6 (29,556.8) |
MExNvoxel% | – | 72.8 (21.5) | – | 73.4 (20.7) |
Extensor VOI | ||||
Nvoxel% | – | 48.6 (16.0) | – | 45.0 (19.5) |
IRExNvoxel | – | 98.1 (82.5) | – | 113.0 (108.9) |
IRExNvoxel% | – | 0.39 (0.21) | – | 0.4 (0.3) |
MExNvoxel | – | 16,553.4 (9817.4) | – | 16,488.1 (10,599.5) |
MExNvoxel% | – | 67.1 (23.7) | – | 60.6 (27.5) |
Flexor VOI | ||||
Nvoxel% | – | 58.1 (16.6) | – | 60.9 (13.8) |
IRExNvoxel | – | 236.1 (116.1) | – | 273.7(150.0) |
IRExNvoxel% | – | 0.27 (0.15) | – | 0.28 (0.16) |
MExNvoxel | – | 64,937.5 (17,987.4) | – | 74,748.5 (21,639.4) |
MExNvoxel% | – | 74.3 (22.3) | – | 76.5 (19.3) |
Physical function | ||||
Muscle strength Knee extension, Nm | ||||
0°/s | – | 103.1 (21.2) | – | 124.1 (35.7) |
60°/s | – | 81.2 (24.8) | – | 91.0 (29.9) |
120°/s | – | 69.3 (20.7) | – | 86.9 (29.1) |
180°/s | – | 60.3 (17.0) | – | 76.9 (26.8) |
Muscle strength knee flexion, Nm | ||||
0°/s | – | 48.7 (17.3) | – | 63.4 (22.8) |
60°/s | – | 38.1 (14.6) | – | 49.0 (20.0) |
120°/s | – | 34.2 (13.8) | – | 45.4 (19.7) |
180°/s | – | 32.4 (12.1) | – | 44.1 (17.9) |
6-min walk distance, m | – | 494.4 (93.8) | – | 541.2 (84.7) |
DCE-MRI perfusion variables
Exercise group | Control group | Comparison | ||
---|---|---|---|---|
Mean (SE) | Mean (SE) | Mean Difference (95% CI) | P-value | |
KOOS changes from baseline | ||||
Pain | 8.5 (2.5) | −2.2 (2.5) | 10.7 (3.3, 18.1) | 0.006 |
Symptoms | 3.7 (3.1) | −0.9 (3.0) | 4.6 (−4.3, 13.6) | 0.298 |
Function in Daily Living | 6.9 (3.0) | 0.1 (2.9) | 6.7 (−2.3, 15.8) | 0.140 |
Knee-Related Quality of Life | 6.2 (3.7) | −2.2 (3.5) | 8.4 (−2.3, 19.0) | 0.118 |
Function in Sports and Recreation | 9.2 (5.8) | −1.0 (5.6) | 10.3 (−6.7, 27.2) | 0.245 |
DCE-MRI perfusion variables changes from baseline | ||||
Total Muscle VOI | ||||
Nvoxel% | 2.6 (2.3) | −5.2 (2.3) | 7.7 (1.0, 14.5) | 0.026 |
IRExNvoxel | − 51.6 (27.8) | − 154.6 (27.0) | 103.0 (22.1, 183.9) | 0.014 |
IRExNvoxel% | −0.03 (0.02) | −0.13 (0.02) | 0.1 (0.03, 0.17) | 0.008 |
MExNvoxel | 1409.8 (3749.7) | − 10,032.9 (3632.9) | 11,443.0 (− 531.4, 22,354.0) | 0.041 |
MExNvoxel% | 2.3 (3.1) | −8.3 (3.0) | 10.6 (1.7, 19.4) | 0.021 |
Extensor VOI | ||||
Nvoxel% | 0.3 (3.2) | −7.1 (3.1) | 7.4 (−1.9, 16.6) | 0.114 |
IRExNvoxel | −19.1(11.9) | −58.6 (11.6) | 39.6 (5.1, 74.1) | 0.026 |
IRExNvoxel% | −0.03 (0.04) | −0.21 (0.04) | 0.18 (0.06, 0.3) | 0.005 |
MExNvoxel | − 1093.6 (1364.8) | − 3532.2 (1323.2) | 2438.6 (− 1.491.4, 6368.6) | 0.215 |
MExNvoxel% | −0.4 (4.6) | −12.0 (4.5) | 11.6 (− 1.8, 25.0) | 0.087 |
Flexor VOI | ||||
Nvoxel% | 3.2 (2.2) | −5.2 (2.1) | 8.5 (2.2, 14.8) | 0.010 |
IRExNvoxel | −31.8 (18.6) | − 96.5 (18.0) | 64.6 (10.4, 118.8) | 0.021 |
IRExNvoxel% | −0.03 (0.02) | − 0.11(0.02) | 0.08 (0.02, 0.14) | 0.015 |
MExNvoxel | 3247.0 (2861.0) | − 7200.6 (2770.1) | 10,448 (2039.6, 18,856.0) | 0.017 |
MExNvoxel% | 3.2 (2.8) | −8.0 (2.7) | 11.1 (3.0, 19.3) | 0.009 |
Physical function changes from baseline | ||||
Muscle strength Knee extension, Nm | ||||
0°/s | −1.0 (4.3) | 4.9 (4.1) | −5.8 (− 18.7, 7.0) | 0.355 |
60°/s | −5.2 (3.0) | 1.0 (2.9) | −6.2 (−15.0, 2.6) | 0.161 |
120°/s | −5.3 (2.8) | −2.5 (2.7) | −2.8 (−11.1, 5.5) | 0.488 |
180°/s | − 2.7 (2.8) | −1.3 (2.7) | −1.4 (−9.8, 7.0) | 0.728 |
Muscle strength knee flexion, Nm | ||||
0°/s | 5.1 (3.0) | 2.2 (2.9) | 3.0 (−6.2, 12.1) | 0.502 |
60°/s | 1.2 (2.4) | 2.5 (2.3) | −1.3 (−8.5, 5.9) | 0.708 |
120°/s | −0.02 (1.8) | 4.0 (1.8) | −4.0 (−9.4, 1.4) | 0.146 |
180°/s | −0.6 (2.0) | 2.3 (2.0) | −2.9 (−9.1, 3.2) | 0.336 |
6-min walk distance, m | 39.8 (13.7) | 1.3 (12.8) | 38.4 (−0.76, 77.6) | 0.054 |
KOOS questionnaire
Physical performance measures
Sensitivity analyses
Ancillary analyses
Estimate (95%CIs) and P-valuea | Proportion mediated (95% CI)a | |
---|---|---|
Total effect | 10.7 (3.3 to 18.1), P = 0.006 | – |
Mediator | ||
TotalMuscle | ||
Nvoxel% | 2.1 (−0.1 to 9.6), P = 0.116 | 0.20 (−0.02 to 1.23) |
IRExNvoxel | 2.3 (−0.4 to 6.3), P = 0.092 | 0.21 (−0.06 to 0.81) |
IRExNvoxel% | 1.9 (−1.2 to 6.0), P = 0.230 | 0.18 (−0.15 to 0.88) |
MExNvoxel | 2.1 (−0.1 to 7.0), P = 0.094 | 0.19 (−0.02 to 0.88) |
MExNvoxel% | 2.1 (−0.1 to 9.5), P = 0.116 | 0.20 (−0.01 to 1.03) |
Extensor | ||
Nvoxel% | 0.6 (−0.7 to 4.3), P = 0.476 | 0.05 (−0.07 to 0.54) |
IRExNvoxel | 0.9 (−1.8 to 3.1), P = 0.468 | 0.09 (−0.26 to 0.35) |
IRExNvoxel% | 1.3 (−3.6 to 5.1), P = 0.496 | 0.12 (−0.43 to 0.53) |
MExNvoxel | 0.2 (−0.6 to 2.3), P = 0.630 | 0.02 (−0.07 to 0.30) |
MExNvoxel% | 0.5 (−0.7 to 3.9), P = 0.494 | 0.05 (−0.09 to 0.44) |
Flexor | ||
Nvoxel% | 2.8 (0.0 to 10.8), P = 0.060 | 0.26 (0.00 to 1.38) |
IRExNvoxel | 2.8 (0.0 to 7.7), P = 0.048 | 0.26 (0.00 to 1.24) |
IRExNvoxel% | 1.8 (−0.7 to 5.5), P = 0.182 | 0.17 (−0.08 to 0.82) |
MExNvoxel | 3.0 (0.1 to 12.3), P = 0.040 | 0.28 (0.01 to 1.71) |
MExNvoxel% | 3.0 (0.1 to 11.5), P = 0.038 | 0.28 (0.01 to 1.46) |