Introduction
Materials and methods
Participants
CT acquisition and reconstruction
Image analysis
Feature type | Method | Parameters |
---|---|---|
First-order | Describe the histogram distribution of voxel signal intensity values without spatial information | Mean, maximum, minimum, range, standard deviation, coefficient of variation, skewness, kurtosis, energy, entropy |
Second-order grey-level co-occurrence matrix (GLCM) | Describe the statistical interrelationships between grey-level pairs with similar or dissimilar signal intensity values within an imaging plane | Autocorrelation, cluster prominence, cluster shade, contrast, correlation, difference entropy, difference variance, dissimilarity, entropy, energy, homogeneity, information measure correlation, inverse difference moment normalised, inverse difference normalised, maximum probability, sum average, sum entropy, sum of squares variance |
Second-order grey-level difference matrix (GLDM) | Describe the grey-level differences of all possible pairs of grey-level distance (d) apart at angle (Θ) | Mean, entropy, variance, contrast |
High-order neighbourhood grey-tone difference matrix (NGTDM) | Describe the signal intensity and spatial interrelationship between each voxel with its direct 26 neighbours | Coarseness, contrast, busyness, complexity, texture strength |
High-order grey-level run length (GLRL) | Describe the spatial interrelationship between neighbouring runs of voxels with the same intensity | Run percentage, high grey-level run emphasis, short-run low grey-level emphasis, short-run high grey-level emphasis, short-run emphasis, long-run emphasis, grey-level non-uniformity, run length non-uniformity, low grey-level run emphasis, long-run low grey-level run emphasis, long-run high grey-level run emphasis, intensity variability, run length variability |
High-order grey-level zone-size matrix (GLZSM) | Describe signal intensity and spatial interrelationship between neighbouring zones with the same intensity | Short-zone emphasis, short-zone low-intensity emphasis, short-zone high-intensity emphasis, long-zone low-intensity emphasis, long-zone high-intensity emphasis, long-zone emphasis, intensity non-uniformity |
Model-based fractal features | Describe repetitive patterns within an image extracted by using filter grids | Fractal dimension mean, fractal dimension SD, fractal lacunarity, Hurst exponent, blanket mean, blanket max |
Statistical analysis
Results
Participants
Radiomics analysis
CT radiomics | 2D regression coefficient (95% CI) | 2D Β value* | 2D p value | 3D regression coefficient (95% CI) | 3D Β value* | 3D p value |
---|---|---|---|---|---|---|
First-order features | ||||||
Mean | − 0.05 (− 0.06, − 0.03) | 0.01 |
< 0.001
| − 0.18 (− 0.30, − 0.05) | 0.01 |
0.005
|
Maximum | − 5.9 (− 6.3, − 5.2) | 0.24 |
< 0.001
| − 6.1 (− 6.8, − 5.3) | 0.27 |
< 0.001
|
Minimum | 3.9 (3.0, 4.8) | 0.04 |
< 0.001
| − 8.0 (− 13.6, − 2.5) | 0.04 |
0.005
|
Range | − 9.8 (− 11.2, − 8.3) | 0.09 |
< 0.001
| 2.0 (− 3.6, 7.6) | 0.01 |
0.48
|
Standard deviation | − 1.27 (− 1.44, − 1.10) | 0.18 |
< 0.001
| − 0.78 (− 1.04, − 0.52) | 0.06 |
< 0.001
|
Coefficient of variation | − 0.022 (− 0.025, − 0.018) | 0.10 |
< 0.001
| − 0.010 (− 0.019, − 0.002) | 0.02 |
0.02
|
Kurtosis | 0.33 (0.21, 0.45) | 0.05 |
< 0.001
| 2.1 (1.4, 2.8) | 0.10 |
< 0.001
|
Skewness | − 0.064 (− 0.078, − 0.052) | 0.08 |
< 0.001
| − 0.18 (− 0.23, − 0.13) | 0.12 |
< 0.001
|
Energy | 0.0010 (0.0007, 0.0015) | 0.04 |
< 0.001
| 0.005 (0.004, 0.007) | 0.11 |
< 0.001
|
Entropy | − 0.008 (− 0.013, − 0.003) | 0.02 |
0.003
| − 0.047 (− 0.060, − 0.035) | 0.10 |
< 0.001
|
Second-order features | ||||||
GLCM Autocorrelation | 8.5 (7.2, 9.9) | 0.19 |
< 0.001
| 68 (54, 82) | 0.11 |
< 0.001
|
GLCM Cluster prominence | 787 (555, 1018) | 0.07 |
< 0.001
| − 70 (− 92, − 48) | 0.10 |
< 0.001
|
GLCM cluster shade | − 28 (− 35, − 20) | 0.12 |
< 0.001
| 4147 (2692, 5602) | 0.09 |
< 0.001
|
GLCM contrast | − 2.9 (− 3.2, − 2.5) | 0.35 |
< 0.001
| − 2.4 (− 3.0, − 1.8) | 0.10 |
< 0.001
|
GLCM correlation | 0.038 (0.034, 0.042) | 0.50 |
< 0.001
| 0.017 (0.014, 0.020) | 0.31 |
< 0.001
|
GLCM difference entropy | − 0.053 (− 0.060, − 0.048) | 0.44 |
< 0.001
| − 0.05 (− 0.06, − 0.04) | 0.16 |
< 0.001
|
GLCM difference variance | − 2.9 (− 3.2, − 2.5) | 0.35 |
< 0.001
| − 2.4 (− 3.0, − 1.8) | 0.10 |
< 0.001
|
GLCM dissimilarity | − 0.23 (− 0.26, − 0.20) | 0.38 |
< 0.001
| − 0.20 (− 0.24, − 0.16) | 0.14 |
< 0.001
|
GLCM entropy | − 0.056 (− 0.063, − 0.050) | 0.37 |
< 0.001
| − 0.09 (− 0.11, − 0.07) | 0.13 |
< 0.001
|
GLCM energy | 0.0003 (0.0003, 0.0004) | 0.30 |
< 0.001
| 0.0010 (0.0008, 0.0012) | 0.16 |
< 0.001
|
GLCM homogeneity | 0.012 (0.011, 0.014) | 0.43 |
< 0.001
| 0.013 (0.011, 0.015) | 0.19 |
< 0.001
|
GLCM Information measure correlation 1 | − 0.010 (− 0.012, − 0.009) | 0.24 |
< 0.001
| − 0.008 (− 0.010, − 0.007) | 0.35 |
< 0.001
|
GLCM information measure correlation 2 | 0.017 (0.014, 0.019) | 0.16 |
< 0.001
| 0.013 (0.010, 0.015) | 0.15 |
< 0.001
|
GLCM Inverse difference moment normalised | 0.0024 (0.0021, 0.0027) | 0.36 |
< 0.001
| 0.0006 (0.0004, 0.0007) | 0.11 |
< 0.001
|
GLCM inverse difference normalised | 0.0052 (0.0046, 0.0057) | 0.39 |
< 0.001
| 0.0027 (0.0022, 0.0032) | 0.14 |
< 0.001
|
GLCM maximum probability | 0.0009 (0.0007, 0.0010) | 0.40 |
< 0.001
| 0.0024 (0.0019, 0.0029) | 0.17 |
< 0.001
|
GLCM sum average | 0.40 (0.33, 0.47) | 0.17 |
< 0.001
| 1.40 (1.11, 1.68) | 0.11 |
< 0.001
|
GLCM sum entropy | 0.000 (− 0.001, 0.002) | 0.01 | 0.76 | − 0.026 (− 0.035, − 0.018) | 0.07 |
< 0.001
|
GLCM Sum of squares variance | 7.1 (5.9, 8.3) | 0.17 |
< 0.001
| 67 (53, 81) | 0.11 |
< 0.001
|
GLDM mean | − 0.23 (− 0.26, − 0.20) | 0.38 |
< 0.001
| − 0.20 (− 0.24, − 0.16) | 0.14 |
< 0.001
|
GLDM entropy | − 0.054 (− 0.060, − 0.048) | 0.44 |
< 0.001
| − 0.05 (− 0.06, − 0.04) | 0.16 |
< 0.001
|
GLDM variance | − 0.96 (− 1.08, − 0.84) | 0.36 |
< 0.001
| − 0.64 (− 0.83, − 0.44) | 0.08 |
< 0.001
|
GLDM contrast | − 2.86 (− 3.21, − 2.50) | 0.35 |
< 0.001
| − 2.38 (− 2.96, − 1.81) | 0.10 |
< 0.001
|
Fractal features | ||||||
Fractal lacunarity + | 0.09 (0.08, 0.10) | 0.55 |
< 0.001
| – | – | 0.12 |
Fractal dimension mean | − 0.029 (− 0.033, − 0.026) | 0.82 |
< 0.001
| – | – | 0.69 |
Fractal dimension SD | 0.011 (0.010, 0.013) | 0.43 |
< 0.001
| – | – | 0.77 |
Hurst exponent | 0.029 (0.026, 0.033) | 0.82 |
< 0.001
| – | – | 0.69 |
Blanket mean | − 0.056 (− 0.062, − 0.050) | 0.25 |
< 0.001
| – | – | 0.41 |
Blanket max | − 0.056 (− 0.062, − 0.050) | 0.25 |
< 0.001
| – | – | 0.41 |
CT radiomics | Regression coefficient (95% CI) | Β value* | p value |
---|---|---|---|
High-order features | |||
NGTDM coarseness | − 0.07 (− 0.09, − 0.05) | 0.05 |
< 0.001
|
NGTDM contrast | − 0.004 (− 0.006, − 0.002) | 0.04 |
0.001
|
NGTDM busyness | 0.025 (0.016, 0.034) | 0.04 |
< 0.001
|
NGTDM complexity | – | – | 0.16 |
NGTDM texture strength | 0.039 (0.024, 0.054) | 0.08 |
< 0.001
|
GLRL run percentage | − 0.010 (− 0.012, − 0.009) | 0.22 |
< 0.001
|
GLRL high grey-level run emphasis | 0.25 (0.17, 0.32) | 0.01 |
< 0.001
|
GLRL short-run low grey-level emphasis # | – | – | 0.85 |
GLRL short-run high grey-level emphasis | 0.16 (0.10, 0.22) | 0.006 |
< 0.001
|
GLRL short-run emphasis | 0.0004 (0.0003, 0.0005) | 0.02 |
< 0.001
|
GLRL long-run emphasis | 48 (37, 58) | 0.11 |
< 0.001
|
GLRL grey-level non-uniformity | − 209 (− 273, − 146) | 0.06 |
< 0.001
|
GLRL run length non-uniformity | – | – | 0.27 |
GLRL low grey-level run emphasis | − 0.009 (− 0.010, − 0.007) | 0.22 |
< 0.001
|
GLRL long-run low grey-level emphasis | 18.9 (11.1, 26.7) | 0.06 |
< 0.001
|
GLRL long-run high grey-level emphasis | 344 (279, 410) | 0.24 |
< 0.001
|
GLRL intensity variability | − 37,623 (− 56,176; − 19,070) | 0.05 |
< 0.001
|
GLRL run length variability | – | – | 0.53 |
GLZLSM short-zone emphasis + | 0.05 (0.04, 0.06) | 0.17 |
< 0.001
|
GLZLSM short-zone low-intensity emphasis # | 5.3 (2.9, 7.7) | 0.13 |
< 0.001
|
GLZLSM short-zone high-intensity emphasis | 0.048 (0.033, 0.063) | 0.17 |
< 0.001
|
GLZLSM long-zone low-intensity emphasis | − 9.8 (− 16.4, − 3.2) | 0.04 |
0.004
|
GLZLSM long-zone high-intensity emphasis | 544,100 (368,325; 719,875) | 0.18 |
< 0.001
|
GLZLSM long-zone emphasis | 47 (35, 59) | 0.09 |
< 0.001
|
GLZLSM intensity non-uniformity | − 145 (− 190, − 102) | 0.14 |
< 0.001
|
GLZLSM zone length non-uniformity | − 11.5 (− 15.3, − 7.7) | 0.10 |
< 0.001
|
GLZLSM zone percentage | − 0.25 (− 0.028, − 0.021) | 0.20 |
< 0.001
|
GLZLSM low-intensity zone emphasis | − 0.015 (− 0.017, − 0.013) | 0.31 |
< 0.001
|
GLZLSM high-intensity zone emphasis | 161 (110, 212) | 0.17 |
< 0.001
|
GLZLSM intensity variability | − 3503 (− 5140, − 1866) | 0.14 |
< 0.001
|
GLZLSM size zone variability | − 339 (− 511, − 167) | 0.13 |
< 0.001
|