Table 2. Characteristics of the patients in the training and validation cohorts.
| Characteristics | Training cohort (n=108) | Validation cohort (n=45) | P† | |||||
|---|---|---|---|---|---|---|---|---|
| Nonluminal (n=39) | Luminal (n=69) | P | Nonluminal (n=16) | Luminal (n=29) | P | |||
| Age, mean ± SD, years | 51.90±9.86 | 48.17±8.95 | 0.048 | 50.00±7.49 | 52.21±10.50 | 0.463 | 0.278 | |
| ADC value, median (IQR) | 1.06 (0.96, 1.23) | 0.98 (0.85, 1.08) | 0.015 | 1.06 (0.90, 1.15) | 0.90 (0.83, 1.08) | 0.046 | 0.322 | |
| TIC, % | 0.664 | 0.900 | 0.137 | |||||
| Wash-out | 29 (74.36) | 48 (69.57) | 13 (81.25) | 24 (82.75) | ||||
| Plateau | 8 (20.51) | 19 (27.53) | 3 (18.75) | 5 (17.25) | ||||
| Wash-in | 2 (5.13) | 2 (2.89) | 0 (0.00) | 0 (0.00) | ||||
| BI-RADS, % | 0.168 | 0.104 | 0.822 | |||||
| 4A | 0 (0.00) | 2 (2.90) | 0 (0.00) | 0 (0.00) | ||||
| 4B | 5 (12.82) | 10 (14.49) | 2 (12.50) | 6 (20.69) | ||||
| 4C | 22 (56.41) | 44 (63.77) | 8 (50.00) | 19 (65.52) | ||||
| 5 | 12 (30.77) | 13 (18.84) | 6 (37.50) | 4 (13.79) | ||||
| Ki-67, % | 0.730 | 0.742 | 0.716 | |||||
| Low | 9 (23.08) | 18 (26.09) | 4 (25.00) | 6 (20.69) | ||||
| High | 30 (76.12) | 51 (73.91) | 12 (75.00) | 23 (79.31) | ||||
| HER2, % | <0.001 | 0.003 | 0.019 | |||||
| Negative | 13 (33.33) | 48 (69.57) | 1 (6.25) | 15 (51.72) | ||||
| Positive | 26 (66.67) | 21 (30.43) | 15 (93.75) | 14 (48.28) | ||||
| Histologic grade, % | 0.001 | 0.017 | 0.531 | |||||
| I and II | 26 (66.67) | 65 (94.20) | 10 (62.50) | 27 (93.10) | ||||
| III | 13 (33.33) | 4 (5.80) | 6 (37.50) | 2 (6.90) | ||||
| Rad-score, median (IQR) | 0.25 (−0.19, 0.58) | 0.98 (0.37, 1.56) | <0.001 | 0.10 (−0.55, 0.53) | 0.81 (0.25, 1.54) | 0.017 | 0.200 | |
P value was obtained from univariate association analysis between each clinicopathological variable and breast cancer type. P† indicates the comparative analysis between the training cohort and the validation cohort. ADC, apparent diffusion coefficient; BI-RADS, breast imaging reporting and data system; HER2, human epidermal growth factor receptor 2; IQR, interquartile range; Rad-score, radiomics score; SD, standard deviation; TIC, time-intensity curve.