The role of elastosonography in the differentiation of parotid gland lesions: report of three cases and review of the literature

Compression Real-time Elastography for Evaluation of Salivary Gland Lesions: A Meta-analysis

OBJECTIVES

To evaluate the performance of compression real-time elastography for differentiation between benign and malignant salivary gland lesions.

METHODS

A systematic literature database search was conducted. Pooled sensitivity, specificity, positive likelihood ratio (LR+), and negative likelihood ratio (LR-) values for real-time elastography were analyzed. Summary receiver operating characteristic (ROC) curves were also constructed. Heterogeneity was evaluated by χ(2) and I(2) tests. I(2) > 50% or P < .05 indicated heterogeneity, and then a random-effects model was applied. A Deek funnel plot was used to assess publication bias. Fagan plot analysis was performed to evaluate the clinical utility of real-time elastography. When heterogeneity was found, subgroup analyses were used to explore the sources of heterogeneity. A sensitivity analysis was conducted by omitting 1 study at a time and examining the influence of each individual study on the overall results.

RESULTS

Nine articles with 581 lesions were included. The pooled sensitivity and specificity of real-time elastography for differentiation between benign and malignant lesions were 76% (95% confidence interval [CI], 65%-85%; 95% prediction interval [PI], 29%-95%) and 73% (95% CI, 62%-81%; 95% PI, 24%-96%), respectively. The LR+ and LR- were 2.81 (95% CI, 1.79-4.39; 95% PI, 0.65-12.16) and 0.33 (95% CI, 0.20-0.55; 95% PI, 0.07-1.69). The area under the ROC curve was 0.81 (95% CI, 0.77-0.84). No publication bias was detected, according to the Deek funnel plot (P = .51). The Fagan plot showed that when pretest probabilities were 25%, 50%, and 75%, positive posttest probabilities were 48%, 74%, and 89%, and negative probabilities were 10%, 25%, and 50%.

CONCLUSIONS

Real-time elastography is a novel supplementary adjunct to conventional sonography for evaluation of salivary gland lesions. However, its overall accuracy is less promising, and biopsy may still be necessary in routine clinical practice.

Diagnostic Accuracy of Real-Time Shear Wave Elastography for Staging of Liver Fibrosis: A Meta-Analysis

BACKGROUND The present meta-analysis, based on previous studies, was aimed to evaluate the test accuracy of real-time shear wave elastography (SWE) for the staging of liver fibrosis. MATERIAL AND METHODS A systematic search on MEDLINE, PubMed, Embase, and Google Scholar databases was conducted, and data on SWE tests and liver fibrosis staging were collected. For each cut-off stage of fibrosis (F≥2, F≥3, and F≥4), pooled results of sensitivity, specificity, and area under summary receiver operating characteristic (SROC) curve were analyzed. The study heterogeneity was evaluated by χ2 and I2 tests. I2>50% or P≤0.05 indicates there was heterogeneity, and then a random-effects model was applied. Otherwise, the fixed-effects model was used. The publication bias was evaluated using Deeks funnel plots asymmetry test and Fagan plot analysis was performed. RESULTS Finally, 934 patients from 8 published studies were included in the analysis. The pooled sensitivity and specificity of SWE for F≥2 were 85.0% (95% CI, 82-88%) and 81% (95% CI, 71-88%), respectively. The area under the SROC curve with 95% CI was presented as 0.88 (95% CI, 85-91%). The pooled sensitivity and specificity of SWE for F≥3 were 90.0% (95% CI, 83.0-95.0%) and 81.0% (95% CI, 75.0-86.0%), respectively, corresponding to an area of SROC of 0.94 (95% CI, 92-96%). The pooled sensitivity and specificity of SWE for F≥4 were 87.0% (95% CI, 80.0-92.0%) and 88.0% (95% CI, 80.0-93.0%), respectively, corresponding to an area of SROC of 0.92 (95% CI, 89-94%). CONCLUSIONS The overall accuracy of SWE is high and clinically useful for the staging of liver fibrosis. Compared to the results of meta-analyses on other tests, such as RTE, TE, and ARFI, the performance of SWE is nearly identical in accuracy for the evaluation of cirrhosis. For the evaluation of significant liver fibrosis (F≥2), the overall accuracy of SWE seems to be similar to ARFI, but more accurate than RTE and TE.

Contrast-enhanced ultrasound in the evaluation of parotid gland lesions: an update of the literature

High-resolution ultrasound is the first line examination for parotid gland diffuse disease and focal lesions, normally using grey-scale and colour-Doppler ultrasound. Unfortunately, grey-scale and colour-Doppler ultrasound features of benign and malignant salivary gland lesions may overlap, particularly with benign tumors, where pleomorphic adenomas are often indistinguishable from malignant lesions. With atypical lesions, contrast-enhanced magnetic resonance imaging is usually the second level imaging modality requested. The introduction of ultrasound contrast agents has opened further possible perspectives to improve the interpretation of parotid diseases, particularly the differentiation between benign and malignant lesions. We present a review of the current literature on contrast-enhanced ultrasound for the assessment of parotid gland lesions, considering all characteristics of the technique, evidence of usefulness, future perspectives and limitations.