Usefulness of 2-D shear wave elastography for the diagnosis of inguinal lymph node metastasis of malignant melanoma and squamous cell carcinoma

The Role of Contrast-Enhanced Ultrasound in the Differential Diagnosis of Tuberous Vas Deferens Tuberculosis and Metastatic Inguinal Lymph Nodes

PURPOSE

To retrospective analysis and summary the features of tuberous vas deferens tuberculosis (VD TB) and inguinal metastatic lymph nodes (MLN) in routine ultrasound (US) and contrast-enhanced US (CEUS) as well as to assess the utility of CEUS in differentiating between the two diseases.

METHODS

The US and CEUS findings of patients with pathologically confirmed tuberous VD TB (n = 17) and inguinal MLN (n = 28), including the number of lesions, presence of bilateral disease, differences in internal echogenicity, a conglomeration of lesions, and blood flow within the lesions, were retrospectively analyzed.

RESULTS

Routine US showed no significant difference in the number of lesions, nodule size, internal echogenicity, sinus tract, or skin rupture; however, significant differences were observed between the two conditions in the conglomeration of lesions (χ² = 6.455; p = 0.023) and the degree, intensity, and echogenicity pattern on CEUS (χ² = 18.865, 17.455, and 15.074, respectively; p = 0.000 for all).

CONCLUSIONS

CEUS can show the blood supply of the lesion, and judge the physical condition of the lesion better than US. Homogeneous, centripetal, and diffuse enhancement should prompt a diagnosis of inguinal MLN, whereas lesions with heterogeneous and diffuse enhancement on CEUS should be considered as VD TB. CEUS has great diagnostic value in differentiating between tuberous VD TB and inguinal MLN.

2D-shear wave elastography in the evaluation of suspicious superficial inguinal lymph nodes: Reproducibility and region of interest selection

Purpose

To assess the ability of 2D-Shear wave elastography (2D-SWE) to evaluate its reproducibility, to define the optimal orientation and size of the region of interest (ROI), and to differentiate benign from malignant inguinal lymph nodes (LNs).

Method

Thirty-two suspicious inguinal LNs from 21 patients were evaluated with 2D-SWE. SWE measurements were obtained in two orthogonal planes. To investigate reproducibility, sensitivity and specificity, circular ROIs with a diameter of 1 mm, 2 mm, 3 mm and 5 mm were placed on the cortex of the LNs. Additionally, one freehand ROI was drawn covering majority of the LN. Two observers performed five sets of SWE measurements for each ROI size. All LNs underwent core needle biopsy or were surgically removed.

Results

The 3 mm ROI for Mean-E in axial plane showed high interrater agreement [intraclass correlation coefficient (ICC) 0.899] with the cut-off value of 7.31 kPa resulting in 88.9% sensitivity and 60.9% specificity for differentiating malignant from benign LNs. In benign LNs, mean elasticity of the ROI was lower (7.68 ± 3.82 kPa; range, 3.41–15.40 kPa) compared to the malignant LNs (15.81 ± 10.61 kPa; range, 3.86–36.45 kPa).

Conclusions

The most reproducible way to measure stiffness in inguinal LNs is a 3 mm circular ROI centered on the cortex of the LN in axial plane. Elasticity values were higher in the malignant LNs reflecting the stiffer nature of the metastatic LNs. 2D-SWE offers a noninvasive ultrasonographic tool to assess superficial inguinal lymph nodes with high reproducibility.