Is sonoelastography a helpful method for evaluation of parotid tumors?

Diagnostic value of shear wave elastography quantification combined with conventional ultrasound in salivary gland tumors

Background

The histopathological classification of salivary gland tumors is extremely complex. The imaging manifestations of some tumors are nonspecific. It is particularly important to improve the value of ultrasound in the diagnosis of salivary gland tumors. This study aimed to analyze the diagnostic value of different parameters of shear wave elastography (SWE) in the quantitative diagnosis of salivary gland tumors, and to evaluate the value of SWE combined with conventional ultrasound.

Methods

The study was conducted retrospectively. Patients who underwent salivary gland tumor resection from April 2021 to November 2022 in the Ninth People's Hospital, Shanghai Jiaotong University School of Medicine were randomly recruited to the study. A total of 305 masses were divided into an elastography group (150 cases) and a control group (155 cases). The control group underwent conventional ultrasonography, whereas the elastography group underwent conventional ultrasonography and elastography. The Young's modulus E of the mass was quantitatively measured in the elastography group, including maximum cross-sectional area (S), maximum Young's modulus (Emax), mean Young's modulus (Emean), and Young's modulus standard deviation (SD). Pathologic diagnosis was used as the reference standard to determine the cut-off of shear wave elastography of salivary gland tumors, and the diagnostic performance of the 2 groups was compared.

Results

In the elastography group, the diagnostic value of Emax·S (the product of the maximum Young's modulus of the mass and the maximum cross-sectional area of the mass) in the differential diagnosis of malignant tumors (MT) and non-malignant tumors (NMT) was the highest, with a sensitivity and specificity of 72.0% and 80.0%, respectively. The diagnostic value of Emax/D (the quotient of the maximum Young's modulus of the mass and the maximum diameter of the mass) in the differential diagnosis of pleomorphic adenoma (PA) and adenolymphoma (AL) was the highest, with a sensitivity and specificity of 62.3% and 82.4%, respectively. The receiver operating characteristic (ROC) curves for the diagnosis of salivary gland tumors were compared between the elastography group and the control group. The area under the curve (AUC) of the elastography group was 0.915, the sensitivity, specificity, and Youden index were 84.0%, 88.0%, and 0.720, respectively. The AUC of the control group was 0.906, the sensitivity, specificity, and Youden index were 76.0%, 90.0%, and 0.660, respectively, which is the main finding of the study.

Conclusions

SWE can be used as a complementary method for the diagnosis of salivary gland tumors, which has certain value in improving the diagnostic performance. As a result, the sensitivity is improved but the specificity is worsened by addition of SWE to B-mode ultrasound and color Doppler flow imaging (CDFI).

Contrast-Enhanced Ultrasound and Strain Elastography for Differentiating Benign and Malignant Parotid Tumors

OBJECTIVES

Preoperative differentiation between benign parotid tumors (BPT) and malignant parotid tumors (MPT) is crucial for treatment decisions. The purpose of this study was to investigate the benefits of combining contrast-enhanced ultrasound (CEUS) and strain elastography (SE) for preoperative differentiation between BPT and MPT.

METHODS

A total of 115 patients with BPT (n=72) or MPT (n=43) who underwent ultrasound (US), SE, and CEUS were enrolled. US and CEUS features and the elasticity score were evaluated. Receiver operating characteristic curve (ROC) analysis was used to assess the diagnostic performance of SE, CEUS, and SE + CEUS with respect to identifying MPT from BPT.

RESULTS

Solitary presentation, larger diameter, irregular shape, ill-defined margin, heterogeneous echogenicity, and calcification on US and higher elasticity score on SE had a significant association with malignancy. MPT also presented an unclear margin, larger size after enhancement, and "fast-in and fast-out" pattern on CEUS. The combination of SE and CEUS was effective for differentiating MPT from BPT (AUC: 0.88, 0.80-0.95), with a sensitivity of 86.0%, specificity of 88.9%, and accuracy of 87.8%, which were significantly higher than the values for SE (AUC: 0.75, 0.66-0.85) and CEUS (AUC: 0.82, 0.73-0.91) alone.

CONCLUSION

The combination of CEUS and SE is valuable for distinguishing MPT from BPT.

Precision Hydrogels for the Study of Cancer Cell Mechanobiology

Cancer progression is associated with extensive remodeling of the tumor microenvironment (TME), resulting in alterations of biochemical and biophysical cues that affect both cancer and stromal cells. In particular, the mechanical characteristics of the TME extracellular matrix undergo significant changes. Bioengineered polymer hydrogels can be instrumental to systematically explore how mechanically changed microenvironments impact cancer cell behavior, including proliferation, survival, drug resistance, and invasion. This article reviews studies that have explored the impact of different mechanical cues of the cells' 3D microenvironment on cancer cell behavior using hydrogel-based in vitro models. In particular, advanced engineering strategies are highlighted for tailored hydrogel matrices recapitulating the TME's micrometer- and sub-micrometer-scale architectural and mechanical features, while accounting for its intrinsically heterogenic and dynamic nature. It is anticipated that such precision hydrogel systems will further the understanding of cancer mechanobiology.

Efficacy of ultrasound shear wave elastography in the diagnosis of salivary gland tumors

PURPOSE

Diagnostic accuracy of fine-needle aspiration cytology (FNAC) as the ability to discriminate between the target condition and health in the evaluation of salivary gland tumors is not perfected yet and false-negative results are possible. The purpose of the present study was to measure and compare the diagnostic accuracy of FNAC performed with conventional B-mode ultrasound and ultrasound with shear wave elastography (SWE) FNAC navigation.

METHODS

The investigators implemented a single-blind randomized study (sealed envelope method). The study population was composed of all patients presenting for evaluation and management of suspected benign or malignant tumors of the major salivary glands between July 2013 and December 2020. The involvement of SWE navigation was the primary predictor variable affecting FNA targeting. The method involved analysis of redistribution of SWE values within the affected gland expressed in kilopascals (kPa) and the four-point ES1 (soft tissue) to ES4 (stiff) scoring. The primary outcome variable was the success in obtaining diagnostic tissue resulting in a histologically confirmed FNAC diagnosis and coded as yes/no. Age and sex of the patients and topographical locations of lesions were covariates. Descriptive and bivariate statistics were computed and the P value was set at .05.

RESULTS

The sample included 132 subjects (male/female 59/73; mean age 54 ± 11 years; 144 tumors). SWE + Group (n = 66) consisted of patients presurgically diagnosed with salivary tumors SWE-guided FNAC and SWE- Group (n = 66) was diagnosed with tumors by conventional ultrasound-(B-mode)-guided FNAC. The SWE-guided FNAC statistically significantly reduced the incidence of false-negative results (n = 0; P = .001) and nondiagnostic cases (n = 3 SWE FNAC vs n = 7 B-mode US FNAC; P = .04). For SWE + Group, the FNAC diagnosis was confirmed by postsurgical histology in 95.5% with 91.0% sensitivity (confidence interval [CI] 0.62 to 0.97) and 84.4% specificity (CI 0.58 to 0.96). For SWE- Group, 81.8% confirmation was obtained (P = .05) with 82.3% sensitivity (CI 0.54 to 0.90) and 74.0% specificity.

CONCLUSION

SWE can increase success in obtaining diagnostic tissue when used for FNAC navigation purposes. We suggest combining both SWE and standard B-mode US methods when the FNAC procedure is performed.

Comparisons among the Ultrasonography Prediction Model, Real-Time and Shear Wave Elastography in the Evaluation of Major Salivary Gland Tumors

We aimed to validate the diagnostic accuracy of a novel sonographic scoring model and compare it with other methods in the evaluation of malignant major salivary gland tumors. We enrolled 138 patients who received neck ultrasound (US) with fine needle aspiration (FNA) and further operations or core needle biopsies for major salivary gland tumors from June 2015 to October 2021. The sonographic scoring model was presented as 2.08 × (vague boundary) + 1.75 × (regional lymphadenopathy) + 1.18 × (irregular or speculated shape) + 1.45 × (absence of posterior acoustic enhancement) + 2.4 × (calcification). We compared the diagnostic accuracy of the sonographic scoring model with shear wave elastography (SWE), real-time elastography (RTE), and US-FNA cytology for differentiating between benign and malignant lesions. The sensitivity, specificity, and accuracy were 58%, 89%, and 85% for the sonographic scoring model, 74%, 62%, and 64% for the SD of SWE with optimal cutoff value of 31.5 kPa, 69%, 70%, and 70% for the 4-point scoring system of RTE, and 74%, 93%, and 91% for US-FNA cytology, respectively. The sonographic scoring model is feasible as assistance in the evaluation of major salivary gland tumors. US-FNA cytology remains the tool of choice in diagnosing malignant salivary gland tumors.

Diagnostic performance of elastosonography in the differential diagnosis of benign and malignant salivary gland tumors: A meta-analysis

Purpose

The clinical practice of elastosonography for the detection of salivary gland tumors is still a controversial issue. The objective of this meta-analysis was to evaluate the effect of elastosonography for the diagnosis of salivary gland tumors and to compare the diagnostic value of elastosonography and conventional ultrasound in the diagnosis of salivary gland tumors.

Methods

A comprehensive literature search through PubMed, EMBASE, and Cochrane Library was carried out from inception to November 2021. Two researchers independently extracted the data from the enrolled papers using a standard data extraction form. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were calculated to evaluate the diagnostic performance of elastosonography. The Quality Assessment of Diagnostic Accuracy Studies—2 (QUADAS-2) tool was utilized to evaluate the quality of each included study. Meta-DiSc version 1.4, Review Manager 5.3, and StataSE 15 were used.

Results

Sixteen studies with a total of 1105 patients with 1146 lesions were included in this meta-analysis. The pooled sensitivity, specificity, PLR, NLR, and DOR of elastosonography for the differentiation between benign and malignant salivary gland tumors were 0.73 (95%CI, 0.66–0.78), 0.64 (95%CI, 0.61–0.67), 2.83 (95%CI, 1.97–4.07), 0.45 (95%CI, 0.32–0.62), and 9.86 (95%CI, 4.49–21.62), respectively, with an AUC of 0.82. Four studies provided data regarding the conventional ultrasound for the differentiation between benign and malignant salivary gland tumors. The pooled sensitivity, specificity, and DOR were 0.62 (95%CI, 0.50–0.73), 0.93 (95%CI, 0.90–0.96), and 25.07 (95%CI, 4.28–146.65), respectively. The meta-regression and subgroup analyses found that assessment methods were associated with significant heterogeneity, and quantitative or semiquantitative elastosonography performed better than the qualitative one.

Conclusions

Elastosonography showed a limited value for diagnosing malignant salivary gland tumors; it could be considered as a supplementary diagnostic technology to conventional ultrasound, and quantitative or semiquantitative elastosonography was superior to the qualitative one.

Diagnostic Performance of Elastography in Malignant Soft Tissue Tumors: A Systematic Review and Meta-analysis

Malignant soft tissue tumors (STTs) are often mistaken for benign tumors, leading to inappropriate treatment including unplanned resection. Elastography, as a non-invasive measurement of tissue mechanical properties, makes use of the different soft tissue elasticity in diverse pathologies to generate information that can be used for diagnostic purposes. Elastography for STTs carries important information that is helpful in differentiating malignant and benign masses. The present study was undertaken to systematically review existing trials on the reliability of elastography in assessment of malignant STTs. A comprehensive literature exploration of the PubMed, EMbase and China National Knowledge Infrastructure databases was conducted for published articles involving the application of elastography in distinguishing malignant STTs. The diagnostic performance of elastography was evaluated with pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and area under the summary receiver operating characteristic curve. Publication bias was also evaluated. This meta-analysis enrolled 18 eligible studies with a total of 1420 patients. The overall number of reported STTs was 1569, of which 478 were classified as positive and 1091 as negative at elastography. The pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of elastography were 0.82 (95% confidence interval: 0.74-0.87), 0.80 (0.71-0.86), 3.99 (2.65-6.01) and 0.23 (0.15-0.34), respectively. The diagnostic odds ratio and area under the curve were 17.36 (8.28-36.38) and 0.88 (0.84-0.90), respectively (Glas et al. 2003). The results of meta-regression analysis revealed that the total number of patients and prevalence of malignant STTs were significant factors in sensitivity, and the year of publication, total number of patients and index test were significant factors affecting study heterogeneity for specificity (p < 0.05). No significant publication bias was observed. This meta-analysis indicates that ultrasound elastography achieves relatively good performance in discriminating between malignant and benign STTs. Nevertheless, further research is needed to verify this finding.

Application value of shear wave elastography in salivary gland tumors

OBJECTIVE

The aims of this study were to retrospectively analyse the values of shear wave elastography (SWE) in differential diagnosis of salivary gland tumors (SGT).

METHODS

A total of 56 patients with salivary gland lump(s) were examined by SWE for measuring and comparing the differences in various Young's modules (malignant tumor (MT) and benign tumor (BT), parotid tumor (PA) and adenolymphomas (AL), etc.). All the cases were confirmed by surgery or fine needle aspiration pathology.

RESULTS

The 56 SGT cases included 10 cases MT, 27 cases of PA, 11 cases of AL, and 8 cases of other BT. There was no statistical significance in Young's modules between group BT and group MT (both P > 0.05); the differences between group PA and group AL were statistically significant (P < 0.05), and the corresponding ROC curve analysis found that the diagnostic value of the maximum Young's modulus was the highest with the best cut-off values and AUC as 32.4 KPa and 0.805. The sensitivity, specificity, and Yoden index of the diagnosis of PA and AL were 70.4%, 81.8%, and 0.522, respectively.

CONCLUSIONS

SWE can differentially diagnose PA and AL while not MT and BT in SGT.

Evaluation of benign parotid gland tumors with superb microvascular imaging and shear wave elastography

Aim of the study: This study aimed to examine the role of superb microvascular imaging and shear wave elastography for the pre-surgical evaluation of common parotid tumors. Material and methods: This single-center prospective study included 37 patients with parotid gland lesions. After institutional review board approval, grayscale, shear wave elastography and superb microvascular imaging ultrasound examinations were performed prior to biopsy or operation. The diagnosis of the lesions was based on cytological/pathological evaluation after the ultrasound examinations. Pleomorphic adenomas and Warthin tumors were compared using the Mann–Whitney U test. A receiver operating characteristic curve analysis was performed to obtain a cut-off value. A multivariate regression analysis was carried out. Results: The mean age of the patients (11 female, 26 male) was 48.2 ± 18. The shear wave elastography parameters of the lesions were not significantly different between pleomorphic adenomas and Warthin tumors, while the vascular index obtained by using superb microvascular imaging was significantly different (p = 0.012). The mean vascular index was 2.9 ± 3.1 in pleomorphic adenomas, and 9.5 ± 9.5 in Warthin tumors. A cut-off value of 4.05 for the vascular index discriminated pleomorphic adenoma and Warthin tumors with 68% sensitivity and 72% specificity (the area under the curve was 0.768). Conclusion: Superb microvascular imaging is a novel ultrasound imaging technique which is useful for the discrimination of pleomorphic adenomas and Warthin tumors.

Shear wave elastography of the submandibular gland in healthy individuals

OBJECTIVES

Shear wave elastography is a rapidly evolving new technique. The purpose of the present study was to determine the sonoelastographic features of the submandibular glands in healthy individuals.

METHODS

We conducted a cross-sectional study of 45 healthy individuals, whose submandibular glands were studied using shear wave elastography. The stiffness of both submandibular glands was measured and its relationships with the age, sex, body mass, body mass index (BMI), and height of the participants were assessed.

RESULTS

The participants had a mean age of 31.82 ± 5.53 years, a mean height of 158.30 ± 7.16 cm, a mean body mass of 57.83 ± 8.84 kg, and a mean BMI of 22.99 ± 2.72 kg/m². The mean shear elastic modulus of the right and left submandibular glands were 18.02 kPa and 19.09 kPa, respectively. Positive correlations were found between the elasticity of the right submandibular gland and the anthropometric parameters.

CONCLUSION

The elastic modulus of the submandibular glands has been determined in healthy individuals and the data generated can serve as a reference for future studies of pathological conditions of these structures.

ACR Appropriateness Criteria® Neck Mass-Adenopathy

A palpable neck mass may be the result of neoplastic, congenital, or inflammatory disease. Older age suggests neoplasia, and a congenital etiology is more prevalent in the pediatric population. The imaging approach is based on the patient age, mass location, and clinical pulsatility. Underlying human papillomavirus-related malignancy should be considered in all age groups. Although the imaging appearance of some processes in the head and neck overlap, choosing the appropriate imaging examination may allow a specific diagnosis, or a limited differential diagnosis. Tissue sampling is indicated to confirm suspected malignancy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Sonoelastography for differential diagnosis between malignant and benign parotid lesions: a meta-analysis

Objectives

To assess the performance of sonoelastography for differential diagnosis between malignant and benign parotid lesions using a meta-analysis.

Methods

An independent literature search of English medical databases, such as PubMed, Embase and Medline (Embase.com), Web of Science, Cochrane Library and Ovid was performed. The diagnostic accuracy of sonoelastography was compared with that of histopathology and/or cytology, which was used as reference standard. The pooled sensitivity, specificity, diagnostic odds ratio (DOR) and area under the curve (AUC) were calculated to evaluate the accuracy of sonoelastography. A meta-regression analysis evaluating imaging mechanisms, shear wave elastography techniques, assessment methods and QUADAS scores was performed.

Results

Ten eligible studies that included a total sample of 711 patients with 725 parotid lesions were included. Sonoelastography showed a pooled sensitivity of 0.67 (95% CI 0.59–0.74), specificity of 0.64 (95% CI 0.60–0.68), DOR of 8.00 (95% CI 2.96–21.63) and an AUC of 0.77. The results of the meta-regression analysis revealed that no heterogeneity was due to the imaging mechanism (p = 0.119), shear wave elastography technique (p = 0.473) or QUADAS score (p = 0.462). However, the assessment method was a significant factor that affected the study heterogeneity (p = 0.035). According to the subgroup analysis, quantitative and semiquantitative methods performed better than qualitative ones.

Conclusion

Overall, sonoelastography has a limited value for differential diagnosis between malignant and benign parotid lesions. Quantitative and semiquantitative methods perform better than qualitative ones.

Key Points

• Overall, sonoelastography has a limited value for differential diagnosis between malignant and benign parotid lesions.

• Quantitative and semiquantitative assessment methods perform better than qualitative ones.

• Semiquantitative and quantitative methods are automatically calculated by an ultrasound machine and are thus less operator-dependent.

Head and neck ultrasound: technical advances, novel applications and the role of elastography

High-resolution ultrasound (US) provides superb anatomical detail in the superficial anatomy of the neck and has become the first-line imaging investigation for neck lumps and a crucial component of clinical pathways. In this article, a wide range of advances in neck US are described with a focus on the emerging role of ultrasound elastography. Selected examples of clinical utility are presented across a spectrum of scenarios with discussion of newer applications, service delivery, and training issues. The changing role of the neck ultrasound practitioner and the future of the technique in the head and neck are considered.

Differential Diagnosis of Parotid Gland Tumors: Role of Shear Wave Elastography

AIM

To create a predictive score for the discrimination between benign and malignant parotid tumors using elastographic parameters and to compare its sensitivity and specificity with standard ultrasound.

METHODS

A total of 124 patients with parotid gland lesions for whom surgery was planned were examined using conventional ultrasound, Doppler examination, and shear wave elastography. Results of the examinations were compared with those ones of histology.

RESULTS

There were 96 benign and 28 malignant lesions in our cohort. Blurred tumor margin alone proved to be an excellent predictor of malignancy with the sensitivity of 79% and specificity of 97%. Enlarged cervical lymph nodes, tumor vascularisation, microcalcifications presence, homogeneous echogenicity, and bilateral occurrence also discriminated between benign and malignant tumors. However, their inclusion in a predictive model did not improve its performance. Elastographic parameters (the stiffness maxima and minima ratio being the best) also exhibited significant differences between benign and malignant tumors, but again, their inclusion did not significantly improve the predictive power of the blurred margin classifier.

CONCLUSION

Even though elastography satisfactorily distinguishes benign from malignant lesions on its own, it hardly provides any additional value in evaluation of biological character of parotid gland tumors when used as an adjunct to regular ultrasound examination.

Importance of Sonoelastography in Assessing Non-Thyroid Neck Masses

Objective

To evaluate the feasibility and value of sonoelastography in assessing non-thyroid neck masses.

Methods

Non-thyroid neck masses requiring surgical interventions were evaluated using conventional B-mode ultrasonography (US) (size, short/long axis rate, shape, hilum, echogenity, calcification, necrosis, and peripheral edema) and sonoelastograpy (SE) with strain ratio (SR) and elasticity score (ES) before surgery. These parameters were compared with the histopathological examination.

Results

In total, 116 non-thyroid neck masses (66 lymph node, 35 parotid gland, eight submandibular gland, and seven cervical mass) of 89 patients (51 men, 38 women) with a mean age of 50.3±15.1 (19-79) years were evaluated. Thirty-seven malignant lymph nodes (23 metastatic and 14 lymphoma), seven malignant parotid tumors, two malignant submandibular tumors, 29 benign lymph nodes, 28 benign parotid lesions, and six benign submandibular lesions were evaluated. Mean SR and ES values of malignant masses were 6.3/3.2 for lymph nodes, 5.5/3.3 for the parotid gland, and 4.2/3 for the submandibular gland. Mean SR and ES values of benign lesions were 2.0/2.1 for lymph nodes, 4.4/3.2 for the parotid gland, and 3.2/3 for the submandibular gland. SR and ES were significantly higher for malignant masses compared with those for benign ones. SR was more predictive than ES in evaluating malignant lymph nodes. The area under the curve was 0.917(0.827-1.00) (p<0.05) for SR in differentiating benign-malignant lymph nodes, and the upper cut-off value was two. SR and ES were higher in the malign parotid and submandibular gland lesions than the benign ones, but the difference was not statistically significant.

Conclusion

Strain ratio value could be a useful parameter in differentiating benign-malignant lymph nodes. More studies are necessary for differentiating benign-malignant parotid and submandibular lesions using SE.

Real-Time Sonoelastography of Parotid Gland Tumors

OBJECTIVES

We sought to determine the performance of real-time sonoelastography in the differential diagnosis of parotid gland tumors.

METHODS

Between April, 2014, and June, 2015, 54 parotid gland masses were examined by ultrasound and strain sonoelastography in 46 patients. Real-time sonoelastography using the elasticity score (E-index), which gives an absolute value between 0 (softest) and 6 (hardest), was performed. Demographic characteristics, histopathologic examination, and difference in elasticity scores between benign and malignant masses were evaluated.

RESULTS

The mean age of the patients was 60.01 ± 2.97 years, and 56.52% of the patients were male (n = 26). Among the 54 parotid gland masses, 44 (81.5%) were benign and 10 (18.5%) were malignant tumors, 63% (n = 34) of the lesions being on the right side. The diagnoses as benign tumors consisted of Warthin tumor (n = 18, 33.3%), pleomorphic adenoma (n = 8, 14.8%) and other benign tumors (n = 18, 33.3%). The mean elasticity score and the size of all tumors were 2.87 ± 0.96 and 23.68 ± 12.38 mm, respectively. The mean elasticity score for benign tumors was 2.75 ± 0.95, and for malignant tumors it was 3.44 ± 0.85 (P = .034).

CONCLUSIONS

According to our results, real-time strain sonoelastography seems to have additional value over routine sonographic evaluation of parotid gland tumors in the differential diagnosis of benign and malignant parotid masses. However, with a small sample of malignant cases and appreciable overlap of the stiffness of benign and malignant masses, caution must be applied because the findings may not be representative of all patients with a parotid gland tumor.

Initial Experience With Ultrasound Elastography for Diagnosis of Major Salivary Gland Lesions

OBJECTIVES

The aim of this study was to evaluate the usefulness of ultrasound elastography, including conventional strain elastography, acoustic radiation force impulse (ARFI)-induced strain elastography, and point shear wave elastography (SWE) for diagnosis of major salivary gland lesions.

METHODS

Forty major salivary gland lesions underwent conventional sonography, conventional strain elastography, ARFI strain elastography, and point SWE before surgery or biopsy. The diagnostic performances of the sonographic and elastographic techniques were assessed with reference to histopathologic results.

RESULTS

There were 32 benign (7 Warthin tumors, 17 pleomorphic adenomas, and 8 other benign lesions) and 8 malignant (1 squamous carcinoma, 2 metastases, 2 mucoepidermoid carcinomas, 1 anaplastic carcinoma, and 2 malignant lymphomas) major salivary gland lesions on pathologic analysis. No conventional sonographic features or conventional strain elastographic scores were found to be associated with malignancy (all P > .05). The ARFI strain elastographic scores between benign and malignant lesions were statistically different (P = .032) and an ARFI strain elastographic score of 4 or greater was highly predictive of malignancy (P= .025). An ARFI strain elastographic score of greater than 3 achieved specificity of 81.3% (26 of 32) and sensitivity of 62.5% (5 of 8) in differentiating benign from malignant lesions. The shear wave velocity on point SWE did not show a significant difference in distinguishing between malignant and benign lesions (6.07 versus 4.43 m/s; P > .05). However, Warthin tumors had a trend to show lower shear wave velocities compared with pleomorphic adenomas (2.84 versus 5.27 m/s; P = .024).

CONCLUSIONS

Acoustic radiation force impulse strain elastography may be potentially useful for diagnosing major salivary gland lesions, whereas conventional strain elastography and point SWE are not helpful.

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.

Evaluation of Parotid Glands With Real-time Ultrasound Elastography in Children

OBJECTIVES

The aim of this study was to determine the strain index for parotid glands in children by using ultrasound elastography.

METHODS

In this prospective study, apparently healthy children were referred from the ear-nose-throat clinic to the radiology clinic for elastographic examinations. Conventional sonographic and elastographic examinations of the parotid glands were performed. A linear 5-12-MHz transducer was used to obtain the images.

RESULTS

A total of 54 children were enrolled in this prospective study. The normal mean strain index value ± SD for the parotid glands was 1.24 ± 0.67 (range, 0.29-1.39) regardless of sex. The mean age of girls was 7.42 ± 2.94 years (range, 3-14 years), and the age of boys was 8.50 ± 3.46 years (range, 4-16 years). The strain index values for the parotid glands in boys was 1.25 ± 0.76, and in girls it was 1.22 ± 0.55. There was no statistically significant difference in the strain index values between girls and boys (P= .986). There was no correlation between the strain index and age (r = 0.026) or body mass index (r = 0.066).

CONCLUSIONS

This study determined the mean strain index values for apparently healthy children. Such information can serve as a baseline from which pathologic parotid diseases can be diagnosed with ultrasound elastography in combination with other sonographic criteria.

Sonoelastography--a useful adjunct for parotid gland ultrasound assessment in patients suffering from chronic inflammation

Background

Shear wave elastography (SWE) is widely used in breast, liver, prostate and thyroid evaluations. Elastography provides additional information if used to assess parotid gland pathology. We assessed parotid glands by means of SWE to compare the parenchyma properties in different types of inflammation.

Material/Methods

Prospective analysis included 78 consecutive patients with parotid gland pathology: sialolithiasis (33), Stensen’s duct stenosis (15), chronic inflammation (10), and primary Sjögren syndrome (pSS) (20) treated at the Department of Otolaryngology, Head and Neck Surgery of PUMS. The primary predictor variable was type of parotid pathology, and secondary predictor variables were patient age and the duration and intensity of complaints. Ultrasound pictures were compared with elastography values of parotid parenchyma.

Results

Mean elasticity values for pSS (111 Kilopascals (kPa), Stensen’s duct stenosis (63 kPa), sialolithiasis (82 kPa), and chronic inflammation (77 kPa) were significantly higher than the mean value for healthy patients (24 kPa). Elasticity increased proportionally to the intensity of complaints: mild (51 kPa), moderate (78 kPa), and strong (90 kPa). Increased elasticity did not correspond with ultrasonographic pictures. In pSS the parenchyma was almost twice as stiff as in chronic inflammation (p=0.02), although subjective complaints were mostly mild or moderate, and the ultrasonographic picture did not present features of fibrosis.

Conclusions

Sonoelastography, by improving routine ultrasonographic assessment, might be a useful tool for parotid evaluations during the course of chronic inflammation. An extraordinarily high degree of stiffness was revealed in pSS despite lack of fibrosis by ultrasonography and moderate subjective complaints, suggesting that sonoelastography could be a valuable diagnostic tool.