FIGURE 1.

FIGURE 2.

FIGURE 3.

Spearman correlation between tumor size and elastography parameters
| Parameter | Spearman’s ρ | p value | R2 (%) |
|---|---|---|---|
| Elastography Index | 0.226 | 0.002 | 5.1 |
| Shear-Wave | 0.250 | 0.001 | 6.3 |
Area under the ROC curve (AUC) for elastography parameters
| Parameter | AUC | SE | p value* | 95% CI (Lower-Upper) |
|---|---|---|---|---|
| Elastog raphy Index | 0.725 | 0.059 | 0.001 | 0.610-0.840 |
| SWE (kPa) | 0.768 | 0.056 | < 0.001 | 0.659-0.877 |
Diagnostic performance of elastography parameters
| SWE | Diagnostic | Sensitivity (%) | Specificity (%) | PPV(%) | N PV(%) | |
|---|---|---|---|---|---|---|
| Malignant (n = 54) | Benign (n = 31) | |||||
| ≥ 47.50 kPa | 43 | 10 | 79.6 | 67.7 | 81.1 | 65.6 |
| < 47.50 kPa | 11 | 21 | ||||
| Elasticity index | ||||||
| ≥ 2.25 | 36 | 9 | 66.7 | 71.0 | 80.0 | 55.0 |
| < 2.25 | 18 | 22 | ||||
| Total | 54 | 31 | ||||
Elastography measurements according to BI-RADS 4A and 4B subcategories
| Parameter | BI-RADS 4a | BI-RADS 4b | p value* |
|---|---|---|---|
| Shear-Wave Elastography (SWE), kPa | 38.0 [29.5–39.5] | 45.0 [39.0–50.0] | < 0.001 |
| Elastography Index | 1.60 [1.20–2.05] | 1.90 [1.50–2.20] | 0.030 |
Binary logistic regression for predictors of malignancy
| Parameter | B | p value | ORc (95% CI) | p value | ORa (95% CI) |
|---|---|---|---|---|---|
| Age | 0.110 | < 0.001 | 1.117 | 0.004 | 1.108 |
| Tumor size | –0.025 | 0.074 | 0.976 | 0.122 | 0.967 |
| Shear-Wave | 0.102 | < 0.001 | 1.107 | 0.793 | 0.846 |
| Elastography | 1.278 | 0.001 | 3.588 | 0.106 | 1.085 |
| Ultrasound | 1.459 | < 0.001 | 4.304 | 0.007 | 2.932 |
Spearman’s Rho correlation between lesion characteristics and elastography measurements
| Rho de Spearman | Elasticity index | SWE (kPa) | ||
|---|---|---|---|---|
| Lesion size (mm) | Spearman’s ρ | 1.000 | 0.226 | 0.250 |
| p - value | 0.002 | 0.001 | ||
| N | 189 | 188 | 189 | |
| Lesion depth | Spearman’s ρ | 1.000 | -0.037 | 0.102 |
| p - value | 0.622 | 0.176 | ||
| N | 177 | 176 | 177 |
Comparison of elastography values according to histopathological diagnosis
| Histopathological Diagnosis | |||
|---|---|---|---|
| Benign (n = 31) | Malignant (n = 54) | p value | |
| Elasticity index | 1.9; [1.4–2.5] | 2.5; [2–2.8] | 0.001 |
| Shear-Wave Elastography (SWE, kPa) | 43; [36–49] | 53; [48–59] | 0.000 |
Binary logistic regression model excluding age
| Parameter | B | p value | Adjusted OR (ORa) | 95% CI (Lower) | 95% CI (Upper) |
|---|---|---|---|---|---|
| Elastography Index | 0.671 | 0.117 | 1.955 | 0.846 | 4.521 |
| SWE (kPa) | 0.079 | 0.011 | 1.082 | 1.018 | 1.150 |
Bootstrap validation of optimal cut-off points for elastography parameters
| Method | Original cut-off | Bootstrap mean | Bootstrap 95% CI | Coefficient of Variation |
|---|---|---|---|---|
| SWE (kPa) | 47.5 | 47.49 | 40.5-51.5 | 4.7% |
| Elastography Index | 2.25 | 2.054 | 1.6-2.367 | 13.0% |
Binary logistic regression model using clinically selected variables
| Parameter | B | p value | Adjusted OR (ORa) | 95% CI (Lower) | 95% CI (Upper) |
|---|---|---|---|---|---|
| Age (years) | 0.110 | < 0.001 | 1.117 | 1.054 | 1.783 |
| Elastography Index | 0.422 | 0.435 | 1.524 | 0.530 | 4.389 |
| SWE (kPa) | 0.094 | 0.016 | 1.099 | 1.017 | 1.186 |
Clinical and radiological characteristics of the cohort
| Variable | n (189) | %/Median (IQR) |
|---|---|---|
| Age (years) | 58 (48-68) | — |
| Family history of cancer | ||
| Yes | 42 | 22.22 |
| No | 140 | 74.07 |
| Not declared | 7 | 3.70 |
| Lesion laterality | ||
| Right | 83 | 43.90 |
| Center | 106 | 56.10 |
| Previous mammography | 189 | |
| Yes | 134 | 70.90 |
| No | 55 | 29.10 |
| Ultrasound BI-RADS category | ||
| 4A | 21 | 11.10 |
| 4B | 70 | 37.00 |
| 4C | 16 | 8.50 |
| 5 | 82 | 43.40 |
| Ultrasound tumor size (mm) | 20 (17-28) | — |
| Lesion depth | 16 (12-20) | |
| Elasticity index | 2.57 (2-3) | — |
| Shear-Wave Elastography (SWE, kPa) | 54 (49-59) | — |
| Histopathological diagnosis | 85 | |
| Malignant | 54 | 63.50 |
| Benign | 31 | 36.50 |
| Breast cancer subtype | n = 35 | |
| Luminal A | 7 | 20.00 |
| Luminal B | 22 | 62.90 |
| HER2-positive | 4 | 11.40 |
| Triple negative | 2 | 5.70 |
| Histological grade | 2 (2-3) | — |
Relationship between BI-RADS category and elastography measurements
| Ultrasound BI-RADS | SWE (kPa) | p value* | Elasticity index | p value* |
|---|---|---|---|---|
| 4A | 38; [29.5–39.5] | 0.001 | 1.6; [1.2–2.05] | 0.001 |
| 4B | 45.5; [39–50] | 1.9; [1.5–2.20] | ||
| 4C | 48; [38–55] | 2.55; [2–2.80] | ||
| 5 | 59; [49–60] | 2.7; [2.15–2.80] |