Table 6.
Proposed algorithm for differentiating between unaffected and metastatic sentinel lymph nodes using available ultrasound techniques—grayscale US, Doppler, CEUS and elastography.
| US Parameter | Pattern | Score | |
|---|---|---|---|
| Gray scale ultrasound | |||
| 1. | S/L ratio | <0.55 | 0 |
| ≥0.55 | 1 | ||
| 2. | Echostructure | Homogeneous | 0 |
| Inhomogeneous | 1 | ||
| Doppler ultrasound | |||
| 3. | Localization | Hilar | 0 |
| Peripheral | 1 | ||
| 4. | Type and distribution | Ordered | 0 |
| Chaotic | 1 | ||
| 5. | RI | <0.54 | 0 |
| ≥0.54 | 1 | ||
| 6. | PI | <0.83 | 0 |
| ≥0.83 | 1 | ||
| Score < 3—unaffected lymph node; Score = 3 CEUS and elastography should be performed; Score ≥ 3 metastatic lymph node should be taken into account | |||
| CEUS | |||
| 1. | Enhancement pattern | Intense, homogeneous | 0 |
| Inhomogeneous ± no enhanced areas | 1 | ||
| 2. | Wash-out time (s) peritumoral ad. | >133 | 0 |
| ≤133 | 1 | ||
| Strain elastography | |||
| 3. | Stiffness | Soft or moderately soft (scores 1 and 2) | 0 |
| Predominantly/moderately stiff or stiff (scores 3,4,5) | 1 | ||
Considering CEUS and elastography: Score ≤ 1—unaffected lymph node; Score ≥ 2—malignant lymph node. Considering all significant US parameters: score = 3—unaffected lymph node: score ≥ 4—malignant lymph node. Legend: S—short axis; L—long axis; RI—resistivity index; PI—pulsatility index.