Table 2.
Texture parameters: mean by flip angle
| 2 (n = 36) | 5 (n = 36) | 10 (n = 36) | 15 (n = 36) | 20 (n = 36) | 25 (n = 36) | 30 (n = 44) | P‐value | Q‐value | |
|---|---|---|---|---|---|---|---|---|---|
| Histogram | |||||||||
| Mean | 248.0 | 246.6 | 246.4 | 247.3 | 247.1 | 247.3 | 247.5 | 0.106 | 0.227 |
| Median | 247.2 | 243.8 | 241.4 | 245.6 | 247.4 | 246.5 | 244.8 | <0.0001 | 0.002 |
| STD | 27.0 | 29.5 | 30.3 | 28.5 | 29.2 | 28.2 | 27.7 | 0.081 | 0.220 |
| Range | 10.2 | 9.3 | 9.5 | 9.7 | 10.2 | 10.1 | 10.0 | 0.693 | 0.958 |
| Geometric mean | 248.6 | 248.3 | 248.2 | 248.4 | 248.3 | 248.4 | 248.5 | 0.104 | 0.227 |
| Harmonic mean | 247.2 | 246.7 | 246.6 | 246.9 | 246.8 | 247.0 | 247.1 | 0.102 | 0.227 |
| 2nd STD | 3.4 | 3.1 | 3.2 | 3.3 | 3.5 | 3.4 | 3.4 | 0.697 | 0.958 |
| STD5 | 4.3 | 4.0 | 4.1 | 4.1 | 4.3 | 4.3 | 4.2 | 0.826 | 0.958 |
| STD9 | 5.1 | 4.9 | 5.1 | 5.0 | 5.3 | 5.2 | 5.2 | 0.946 | 0.992 |
| 4th moment | 2166675.3 | 2993396.8 | 3359004.4 | 2519117.0 | 3053199.6 | 2557749.2 | 2269343.1 | 0.298 | 0.559 |
| IQR | 39.0 | 41.3 | 41.5 | 40.2 | 40.2 | 39.9 | 39.4 | 0.362 | 0.603 |
| Entropy | 7.5 | 7.4 | 7.3 | 7.4 | 7.0 | 7.0 | 7.1 | <0.0001 | 0.002 |
| GLCM | |||||||||
| Entropy | 2.7 | 2.3 | 2.1 | 2.4 | 2.3 | 2.4 | 2.4 | 0.021 | 0.118 |
| Contrast | 18.0 | 14.3 | 12.7 | 16.4 | 17.5 | 17.5 | 18.3 | 0.001 | 0.011 |
| Correlation | 0.92 | 0.94 | 0.95 | 0.93 | 0.92 | 0.92 | 0.92 | 0.019 | 0.118 |
| Energy | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.087 | 0.220 |
| Homogeneity | 0.53 | 0.56 | 0.57 | 0.55 | 0.54 | 0.54 | 0.54 | 0.036 | 0.135 |
| GLRL | |||||||||
| SRE | 0.09 | 0.11 | 0.13 | 0.11 | 0.11 | 0.11 | 0.11 | 0.756 | 0.958 |
| LRE | 0.09 | 0.11 | 0.13 | 0.11 | 0.11 | 0.11 | 0.11 | 0.813 | 0.958 |
| GLN | 0.09 | 0.11 | 0.13 | 0.11 | 0.11 | 0.11 | 0.10 | 0.861 | 0.969 |
| RLN | 0.09 | 0.11 | 0.13 | 0.11 | 0.11 | 0.11 | 0.11 | 0.801 | 0.958 |
| RP | 174.7 | 149.3 | 134.2 | 164.2 | 172.6 | 172.8 | 180.9 | 0.988 | 0.992 |
| LGRE | 174.7 | 149.0 | 133.5 | 163.9 | 172.1 | 171.7 | 179.6 | 0.986 | 0.992 |
| HGRE | 178.1 | 153.7 | 137.9 | 167.8 | 176.3 | 175.6 | 184.2 | 0.989 | 0.992 |
| SRLGE | 173.5 | 147.8 | 132.6 | 162.7 | 171.1 | 171.2 | 179.2 | 0.992 | 0.992 |
| SRHGE | 2917.7 | 2167.3 | 1952.6 | 2589.0 | 2569.0 | 2592.7 | 2549.7 | 0.830 | 0.958 |
| LRLGE | 3424.4 | 2631.8 | 2429.1 | 3029.8 | 3003.8 | 3049.7 | 2988.9 | 0.806 | 0.958 |
| LRHGE | 2910.0 | 2195.3 | 2006.0 | 2568.6 | 2571.9 | 2606.3 | 2569.7 | 0.656 | 0.958 |
| Law's features | |||||||||
| L1 | 192705.6 | 192761.2 | 192439.2 | 193311.5 | 195378.8 | 194563.7 | 193770.3 | 0.733 | 0.958 |
| L2 | 16489.5 | 16373.4 | 16323.5 | 16576.5 | 17381.4 | 17285.1 | 16808.4 | 0.001 | 0.011 |
| L3 | 6162.2 | 6141.1 | 6255.8 | 6155.8 | 6387.6 | 6363.1 | 6304.5 | 0.073 | 0.219 |
| L4 | 38082.9 | 37979.5 | 37990.6 | 38104.2 | 38882.5 | 38666.9 | 38384.9 | 0.424 | 0.681 |
| L5 | 4816.5 | 4812.1 | 4769.3 | 4869.8 | 5128.8 | 5112.0 | 4929.7 | 0.034 | 0.135 |
| L6 | 4024.3 | 4032.9 | 3989.2 | 4066.0 | 4269.3 | 4269.7 | 4111.7 | 0.027 | 0.135 |
| L7 | 3002.0 | 3000.4 | 3081.4 | 3010.1 | 3136.7 | 3145.4 | 3091.9 | 0.035 | 0.135 |
| L8 | 9396.0 | 9481.2 | 9217.9 | 9434.4 | 10117.2 | 10063.3 | 9574.5 | 0.010 | 0.090 |
| L9 | 18404.7 | 18234.2 | 18211.3 | 18321.4 | 18878.1 | 18750.6 | 18650.3 | 0.199 | 0.407 |
| GLGM | |||||||||
| MGR | 14.5 | 13.4 | 13.5 | 14.1 | 13.1 | 13.4 | 12.7 | 0.329 | 0.569 |
| VGR | 11028.3 | 10337.9 | 10427.8 | 10781.4 | 9984.6 | 10181.8 | 9640.4 | 0.213 | 0.417 |
| Skewness | 8.5 | 8.8 | 8.7 | 8.7 | 9.1 | 9.0 | 9.3 | 0.088 | 0.220 |
| Kurtosis | 78.1 | 83.2 | 82.1 | 81.4 | 89.2 | 88.6 | 94.6 | 0.045 | 0.151 |
| Mean skewness | 0.46 | 0.80 | 0.92 | 0.62 | 0.60 | 0.58 | 0.54 | 0.020 | 0.118 |
| Mean kurtosis | 2.8 | 3.1 | 3.4 | 3.0 | 3.2 | 3.1 | 3.1 | 0.047 | 0.151 |
| Mean laws | 300502.0 | 300676.9 | 300393.7 | 301260.7 | 307050.4 | 305634.3 | 303027.0 | 0.320 | 0.569 |
Mean texture analysis features variation with changes in flip angle. n: number of contoured slices; STD: standard deviation; STD5: 5‐neighborhood standard deviation; STD9: 9‐neighborhood standard deviation; IQR: indicates interquartile range; GLCM: gray‐level co‐occurrence matrix; GLRL: gray‐level run length; SRLGE: short‐run low gray‐level emphasis; SRHGE: short‐run high gray‐level emphasis; GLGM: gray‐level gradient matrix; SRE: short‐run emphasis; LRE: long‐run emphasis; GLN: gray‐level nonuniformity; RLN: run‐length nonuniformity; RP: run percentage; LGRE: low gray‐level run emphasis; HGRE: high gray‐level run emphasis; SRLGE: short‐run low gray‐level emphasis; SRHGE: short‐run high gray‐level emphasis; LRLGE: long‐run low gray‐level emphasis; LRHGE: long‐run high gray‐level emphasis; MGR: mean gradients; VGR: variance of gradients.
Bold indicates statistically significant as determined with the two‐tailed t‐test and false detection analyses (Q < 0.05).