The aim of this study was to evaluate the diagnostic performance of quantitative shear wave velocity (SWV) measurement on acoustic radiation force impulse (ARFI) elastography for differentiation between benign and malignant thyroid nodules using meta-analysis. The databases of PubMed and the Web of Science were searched. Studies published in English on assessment of the sensitivity and specificity of ARFI elastography for the differentiation of thyroid nodules were collected. The quantitative measurement of ARFI elastography was evaluated by SWV (m/s). Meta-Disc Version 1.4 software was used to describe and calculate the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and summary receiver operating characteristic curves. We analyzed a total of 13 studies, which included 1,854 thyroid nodules (including 1,339 benign nodules and 515 malignant nodules) from 1,641 patients. The summary sensitivity and specificity for differential diagnosis between benign and malignant thyroid nodules by SWV were 0.81 (95% confidence interval [CI]: 0.77-0.84) and 0.84 (95% CI: 0.81-0.86), respectively. The pooled positive and negative likelihood ratios were 5.21 (95% CI: 3.56-7.62) and 0.23 (95% CI: 0.17-0.32), respectively. The pooled diagnostic odds ratio was 27.53 (95% CI: 14.58-52.01), and the area under the summary receiver operating characteristic curve was 0.91 (Q* = 0.84). In conclusion, SWV measurement on ARFI elastography has high sensitivity and specificity for differential diagnosis between benign and malignant thyroid nodules and can be used in combination with conventional ultrasound.

To evaluate the diagnostic performance of shear wave arrival time contour (SWATC) display for the diagnosis of breast lesions and to identify factors associated with the quality of shear wave propagation (QSWP) in breast lesions. This study included 277 pathologically confirmed breast lesions. Conventional B-mode ultrasound characteristics and shear wave elastography parameters were computed. Using the SWATC display, the QSWP of each lesion was assigned to a two-point scale: score 1 (low quality) and score 2 (high quality). Binary logistic regression analysis was performed to identify factors associated with QSWP. The area under the receiver operating characteristic curve (AUROC) for QSWP to differentiate benign from malignant lesions was 0.913, with a sensitivity of 91.9%, a specificity of 90.7%, a positive predictive value (PPV) of 74.0%, and a negative predictive value (NPV) of 97.5%. Compared with using the standard deviation of shear wave speed (SWSSD) alone, SWSSD combined with QSWP increased the sensitivity from 75.8% to 93.5%, but decreased the specificity from 95.8% to 89.3% (P < 0.05). SWSSD was identified to be the strongest factor associated with the QSWP, followed by tumor malignancy and the depth of the lesion. In conclusion, SWATC display may be useful for characterization of breast lesions.

OBJECTIVE: To investigate the stiffness distribution in the ablated zone after radiofrequency ablation (RFA), we used a device called tissue elastometer based on gross liver samples. MATERIALS: AND METHODS: Twelve freshly excised porcine livers were subject to RFA under a same setup to form elliptic ablated samples. Each sample was cut open for gross examination, and then the surface of the section plane was sliced into one piece for Young's modulus test using the tissue elastometer. Five test points along the long-and short-axis on each piece were selected to evaluate stiffness distribution respectively. Among them, four points distributed equidistantly from center to boundary in the ablated zone and one was in the unablated zone. RESULTS: In the ablated zone, we found the Young's moduli were significantly different among the four test points both in long-(F = 99.04, p < 0.001) and short-axis (F = 79.47, p < 0.001) directions. The Young's modulus showed a downtrend in each direction, and was linearly related to the distance from the center to the test point (for long axis, R 2 = 0.968; for short axis, R 2 = 0.984, both p < 0.001). A more significant downtrend was observed in short-axis direction. The Young's moduli gained from the inner edge of ablated zone were comparable and significantly higher than those from the outer edge for both directions. The maximum value of 24.71kPa for Young's modulus was the appropriate threshold to ensure the tissues were necrotic completely. CONCLUSION: The stiffness inside the ablated zone represented a radial distribution with downtrend, following a linear law. The stiffness at the inner edge of ablated zone is stable and significantly higher than that at the outer edge. The maximum value of 24.71 kPa close to the inner edge of Wz may be used as the standard of complete ablation.