Fig 1.
B-mode and elastography images in axial plane of an inguinal lymph node (LN) from a 68-year old patient with vulvar cancer.
Although the B-mode image shows a slightly rounded LN, elastography shows the LN as blue (soft) indicating benign etiology. In histopathology, the inguinal lymph nodes proved to be benign.
Fig 2.
SWE measurements with different ROI sizes in axial plane.
A 7 mm inguinal LN of a 70-year old woman with vulvar cancer is shown in B-mode image (left). The same LN is illustrated with five 2 mm (middle image) and 3 mm (right image) SWE ROIs. ROIs are centered evenly on the 4 mm cortex to cover majority of it. The Mean-E values were 7.8 kPa and 7.0 kPa with 2 mm and 3 mm ROIs accordingly. The LN proved to be histopathologically benign.
Fig 3.
Ultrasound images and histopathology of a micrometastatic inguinal LN of a 67-year old woman with vulvar cancer.
B-mode and elastography images (upper images) illustrate a superficial inguinal LN with abnormal focal cortical thickening. SWE demonstrated Mean-E value of 9.68 kPa and Max-E value of 11.46 kPa with 3 mm ROI in the axial plane. Histopathological analysis revealed a micrometastatic 1 mm deposit of squamocellular carcinoma. HE and cytokeratin stainings are illustrated in the lower row. atypical nuclei show variation in their size and shape. Additionally metastatic cell nuclei stain positive (brown) in cytokeratin staining (scale bar 1 mm).
Table 1.
Patient demographics and lymph node (LN) characteristics.
Table 2.
Histopathology of the core biopsy samples or removed inguinal lymph nodes (N = 32).
Table 3.
Intraclass correlation coefficient (ICC) for different regions of interest (ROIs).
Table 4.
Effect of different parameters on reproducibility of SWE elastography, assessed by intraclass correlation coefficient (ICC) values.
Fig 4.
Receiver operating characteristic (ROC) curves of SWE ROIs with the highest AUC values.
Axially placed 2 mm and 3 mm ROIs yielded the best results with Mean-E (88.9% sensitivity, 56.5% specificity and 88.9%, 60.9% respectively) and 3 mm Max-E (77.8% sensitivity and 69.4% specificity).
Fig 5.
Boxplots of several different types of ROIs.
Boxplots of axial 3 mm, 5 mm and freehand ROI and sagittal 3 mm ROIs in benign vs. malignant lymph nodes with the elasticity cut off values (kPa) from the ROC-curve (black dotted line). Axial ROIs demonstrated better diagnostic performance than sagittal ROIs.