Quantitative ADC parameters from histogram analysis of tumors in the oropharynx and oral cavity at 1.5T and 3T and for all tumors together irrespective of field strength (pooled data)
| Histogram-Based ADC Parameters | 1.5T (n = 45) | 3T (n = 60) | Pooled Data (n = 105) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| HPV− (n = 33) (mean ± SD) | HPV+ (n = 12) (mean ± SD) | P Valuea | HPV− (n = 51) (mean ± SD) | HPV+ (n = 9) (mean ± SD) | P Valuea | HPV− (n = 84) (mean ± SD) | HPV+ (n = 21) (mean ± SD) | P Valuea | |
| Mean ADC (× 10−6 mm2/s) | 1158 ± 183 | 989 ± 188 | .004 | 1201 ± 157 | 1046 ± 167 | .02 | 1184 ± 168 | 1014 ± 178 | <.001 |
| Median ADC (×10−6 mm2/s) | 1135 ± 193 | 936 ± 198 | .003 | 1177 ± 162 | 1016 ± 170 | .03 | 1161 ± 175 | 970 ± 187 | <.001 |
| Minimum ADC (× 10−6 mm2/s) | 422 ± 251 | 379 ± 172 | .36 | 441 ± 238 | 286 ± 207 | .10 | 433 ± 242 | 339 ± 188 | .09 |
| 25 Quartile (× 10−6 mm2/s) | 977 ± 162 | 813 ± 172 | .008 | 1004 ± 151 | 900 ± 165 | .13 | 993 ± 155 | 850 ± 171 | <.001 |
| 75 Quartile (× 10−6 mm2/s) | 1318 ± 216 | 1115 ± 219 | .003 | 1374 ± 183 | 1163 ± 180 | .005 | 1352 ± 197 | 1136 ± 200 | <.001 |
| Interquartile range (× 10−6 mm2/s) | 341 ± 111 | 302 ± 79 | .33 | 371 ± 114 | 263 ± 68 | .003 | 359 ± 113 | 285 ± 75 | .003 |
| Skewness | 0.362 ± 0.647 | 1.012 ± 0.546 | .004 | 0.424 ± 0.416 | 0.804 ± 0.461 | .02 | 0.399 ± 0.516 | 0.923 ± 0.510 | <.001 |
| Excess kurtosis | 0.841 ± 0.116 | 1.728 ± 1.250 | .03 | 0.514 ± 0.872 | 2.207 ± 1.583 | .001 | 0.643 ± 0.982 | 1.934 ± 1.386 | <.001 |
↵a P values (Wilcoxon rank sum test) are indicated for the comparisons between HPV+ and HPV− HNSCCs.