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

Does ultrasound elastography have a role as a diagnostic method for Sjögren's syndrome in the salivary glands? A systematic review

OBJECTIVE

This systematic review was performed to examine the usefulness of salivary gland ultrasound elastography (USE) as a diagnostic tool for Sjögren's syndrome (SjS).

METHODS

Electronic databases (MEDLINE, EMBASE, the Cochrane Library, and Web of Science: Science Citation Index) were searched to identify studies using USE to diagnose SjS from database inception to 15 July 2022. The primary outcome was improved diagnostic accuracy for SjS with the use of USE. Risk of bias and applicability concerns were assessed using the GRADE system, which is continuously developed by the GRADE Working Group.

RESULTS

Among 4550 screened studies, 24 full-text articles describing the applications of USE to diagnose SjS were reviewed. The overall risk of bias was determined to be low for 17 of the 24 articles, medium for 5, and high for 2. Articles comparing patients with SjS and healthy subjects reported high diagnostic accuracy of USE, with most results showed statistically significant differences (parotid glands: 15 of the 16 articles, submandibular glands: 11 of the 14 articles).

CONCLUSIONS

This systematic review suggests that the assessment of salivary glands using USE is a useful diagnostic tool for SjS.

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.

Shear wave elastography as a potential additional diagnostic tool in primary Sjögren's syndrome: an observational study

The primary aim of this study was to verify if shear wave elastography can be used to evaluate salivary gland involvement in primary Sjögren's syndrome (pSS). The secondary objective was to establish an accurate cut-off value for parotid and submandibular salivary gland stiffness and to verify whether there are any distinctions among pSS patients with or without subjective mouth dryness. This prospective study included 45 patients with pSS (2016 ACR/EULAR classification criteria) and 108 healthy controls. All subjects underwent bilateral shear wave elastography of the parotid and submandibular salivary glands. Clinical data of pSS patients were collected and compared to elastography results. Patients with pSS had significantly higher shear wave elastography values for the parotid and submandibular salivary glands than the controls. There were no statistical differences in SWE values between patients with or without mouth dryness. The optimal cut-off value (mean value of 4 salivary glands shear wave elastography results) to distinguish patients with or without pSS was 13.19 kPa with sensitivity = 97.8% and specificity = 100.0%. It was, therefore, confirmed that shear wave elastography measurement of salivary glands has strong predictive ability in pSS detection (AUC 97.8%, 95% CI 93.4-100.0%). Shear wave elastography seems to be a promising, non-invasive and simple quantitative adjunct test to support the diagnosis of pSS with good sensitivity and specificity. More extensive prospective studies are needed to standardize a study protocol.

Preliminary Study on the Diagnostic Performance of a Deep Learning System for Submandibular Gland Inflammation Using Ultrasonography Images

This study was performed to evaluate the diagnostic performance of deep learning systems using ultrasonography (USG) images of the submandibular glands (SMGs) in three different conditions: obstructive sialoadenitis, Sjögren’s syndrome (SjS), and normal glands. Fifty USG images with a confirmed diagnosis of obstructive sialoadenitis, 50 USG images with a confirmed diagnosis of SjS, and 50 USG images with no SMG abnormalities were included in the study. The training group comprised 40 obstructive sialoadenitis images, 40 SjS images, and 40 control images, and the test group comprised 10 obstructive sialoadenitis images, 10 SjS images, and 10 control images for deep learning analysis. The performance of the deep learning system was calculated and compared between two experienced radiologists. The sensitivity of the deep learning system in the obstructive sialoadenitis group, SjS group, and control group was 55.0%, 83.0%, and 73.0%, respectively, and the total accuracy was 70.3%. The sensitivity of the two radiologists was 64.0%, 72.0%, and 86.0%, respectively, and the total accuracy was 74.0%. This study revealed that the deep learning system was more sensitive than experienced radiologists in diagnosing SjS in USG images of two case groups and a group of healthy subjects in inflammation of SMGs.

Ultrasonography predicts the results of labial salivary gland biopsy in patients with suspected Sjögren's syndrome: a matrix risk model

Objective:

Although a positive result of labial salivary gland biopsy (LSGB) is critical for the diagnosis of Sjögren’s syndrome, rheumatologists prefer assessing the non-invasive objective items and hope to learn the predicted probability of positive LSGB before referring patients with suspected Sjögren’s syndrome to receive biopsy. This study aimed to explore the predictive value of combined B-mode ultrasonography (US) and shear-wave elastography (SWE) examination on LSGB results.

Methods:

A derivation cohort and later a validation cohort of patients with suspected Sjögren’s syndrome were recruited. All participants received clinical assessments, B-mode US and SWE examination on bilateral parotid and submandibular glands before LSGB. Positive LSGB was defined by a focus score ⩾1 per 4 mm² of glandular tissue.

Results:

In the derivation cohort of 91 participants, either the total US scores or the total SWE values of four glands significantly distinguished patients with positive LSGB from those with negative results (area under the curve (AUC) = 0.956, 0.825, both p < 0.001). The positive predictive value (PPV) was 100% in patients with total US scores ⩾9 or with total SWE values ⩾33 kPa. The negative predictive value (NPV) was 100% in patients with total US scores <5, but 68% in patients with total SWE values <27 kPa. A matrix risk model was derived based on the combination of total US scores and total SWE values. Patients can be stratified into high, moderate, and low risk of positive LSGB. In the validation cohort of 52 participants, the PPV was 94% in the high-risk subpopulation and the NPV was 93% in the low-risk subpopulation.

Conclusion:

A novel matrix risk model based on the combined B-mode US and SWE examination can help rheumatologists to make a shared decision with suspected Sjögren’s syndrome patients on whether the invasive procedure of LSGB should be performed.

Combination of high-frequency ultrasound and virtual touch tissue imaging and quantification improve the diagnostic efficiency for mild carpal tunnel syndrome

Background

Carpal tunnel syndrome (CTS) is the most common entrapment symptom in the peripheral nerves. High-frequency ultrasound (HFUS) is widely used in the diagnosis of CTS. Virtual Touch Tissue Imaging and Quantification (VTIQ), which provides more information about the hardness of organization, is used to diagnose CTS. However, the data of diagnostic value of them in various degrees of CTS are limited. Whether the combination of HFUS and VTIQ can improve the diagnostic efficiency also remains unknown. The study aimed to explore the diagnostic value of HFUS and VTIQ in various degrees of CTS and whether combination of HFUS and VTIQ could improve the diagnostic efficiency of CTS.

Methods

A collection and analysis of 133 CTS patients and 35 volunteers from January 2016 to January 2019 were performed. We compared the clinical characteristics, cross-sectional area (CSA) value and shear wave velocity SWV_mean value of CTS group with volunteer group.

Results

The CSA value and SWV_mean value of CTS cohort were significantly higher than volunteer group (10.79 ± 2.88 vs. 8.06 ± 1.39, p < 0.001, 4.36 ± 0.95 vs. 3.38 ± 1.09, p < 0.001, respectively). The area under the curve (AUC) of receiver operating characteristic (ROC) curve of CSA value and SWV_mean value were 0.794 and 0.757, respectively. Hierarchical analysis of CSA value and SWV_mean value showed that the AUC in the moderate and severe CTS group were higher than in mild CTS group. Furthermore, the CSA value combined with SWV_mean value used to diagnose mild CTS was 0.758, which was higher than that of single CSA value or single SWV_mean value.

Conclusions

Both HFUS and VTIQ technology were feasible to evaluate CTS. HFUS was suitable for use in diagnosis of moderate and severe CTS. For mild CTS, combination of HFUS and VTIQ was relevant to improve the diagnostic efficiency of CTS.

Narrative review of multiparametric ultrasound in parotid gland evaluation

Disorders affecting parotid gland represent a heterogeneous group comprising congenital, inflammatory and neoplastic diseases which show a focal or diffuse pattern of appearance. The differentiation of neoplastic from non-neoplastic conditions of parotid glands is pivotal for the diagnostic imaging. Frequently there is evidence of overlapping between the clinical and the imaging appearance of the various pathologies. The parotid gland is also often object of study with the combination of different techniques [ultrasound-computed tomography-magnetic resonance imaging (US-CT-MRI), ex.]. Compared to other dominant methods of medical imaging, US has several advantages providing images in real-time at lower cost, and without harmful use of ionizing radiation and of contrast enhancement. B-mode US, and the microvascular pattern color Doppler are usually used as first step evaluation of parotid lesions. Elastography and contrast-enhanced US (CEUS) has opened further possible perspectives to improve the differentiation between benign and malignant parotid lesions. The characterization of the parotid tumors plays a crucial role for their treatment planning and for the prediction of possible surgical complications. We present, here an updated review of the most recurrent pathologies of parotid gland focusing on the diagnostic power of multiparametric US including CEUS and ultrasound elastography (USE); limitations, advantages and the main key-points will be presented.

Shear wave elastography as a new method to identify parotid lymphoma in primary Sjögren Syndrome patients: an observational study

Parotid non-Hodgkin lymphoma (NHL) in primary Sjögren syndrome (pSS) has no specific biomarker for diagnosis. Salivary glands ultrasound (US) is largely used, but its contribution in detecting parotid NHL has not been established. The aim of our study was to determine the added value of bidimensional shear wave elastography (2D-SWE) in pSS diagnosis and to determine its accuracy in identifying parotid NHL. Grey-scale US (GSUS) and 2D-SWE of salivary glands were performed in 35 patients with pSS and 35 healthy controls. The GSUS scores were calculated and the mean of three SWE consecutive measurements was used to appreciate the gland stiffness. SWE increase the diagnostic rate at a cut-off of 6.45 kPa (from 88.6 to 94.2%, p < 0.001) only if applied in patients with insufficient GSUS criteria for pSS diagnosis. The parotid glands with NHL (8 patients, all mucosa-associated lymphoid tissue type) had hyperechoic bands in more than half of the glandular parenchyma (in 68.75% of the glands), large hypoechoic area > 20 mm (all glands), traced gland area over 5 cm² (all glands), parotid US score greater than 13 (in 68.75% of the glands), and high stiffness (elasticity modulus 13.9 ± 4.08 vs 6.32 ± 2.24) (all p < 0.001). These findings give high sensitivity (92.3%), specificity (100%), and positive (100%) and negative predictive values (98.3%) for NHL identification. The rest of GSUS findings did not correlate with the classic risk factors for lymphoma development (all p > 0.05). 2D-SWE had added value for pSS diagnosis in cases where GSUS aspect is normal or nonspecific. The higher stiffness of parotid NHL can be used for early diagnosis, biopsy guidance, and, possible, for treatment monitoring.

Imaging methods in primary Sjögren's syndrome as potential tools of disease diagnostics and monitoring

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease that affects exocrine glands, especially salivary and lacrimal glands, leading to their progressive destruction. With highly differentiated clinical course the approach to the definition of pSS is constantly evolving and the pSS classification criteria have been modified over the past years. In the past sialography and scintigraphy were frequently used in pSS diagnostics. Recently no imaging method has been included in the pSS classification criteria. That raises the question about the benefits of using novel imaging techniques such as ultrasonography, elastography and magnetic resonance imaging to diagnose and monitor pSS patients. The purpose of this review is to evaluate the advantages and limitations of widely used imaging methods in pSS and their possible future development.

Strain and shear wave ultrasound elastography in evaluation of chronic inflammatory disorders of major salivary glands

OBJECTIVE

The aim of this study was to assess chronic inflammatory conditions of major salivary glands by ultrasound elastography.

METHODS

21 patients with chronic inflammatory conditions of major salivary glands and 21 healthy adult volunteers were included in this study. All participants underwent B-mode sonography and ultrasound elastography. The diagnostic performance of strain ratio and shear wave velocity was evaluated by sensitivity and specificity at the optimum cutoff point and the area under the receiver operating characteristic curve.

RESULTS

Cases showed statistically significant higher median strain ratio of parotid and submandibular gland than control group (p-value = 0.001). Total cases showed statistically significant higher median scores than control group (p-value < 0.001). At cut-off value of (1.13); diagnostic accuracy, sensitivity and specificity were 97.6, 95.2 and 100% respectively with AUROC 0.954 and confidence interval: 0.840-0.995. Cases showed statistically significant higher median shear wave velocity of parotid gland than control group (p-value = 0.022), with no statistically significant difference in submandibular gland in the two groups (p-value = 0.216). Total cases showed statistically significant higher median scores than control group (p-value < 0.001). At cut-off value of (23.5), diagnostic accuracy was 78.6% with a sensitivity of 81% and specificity of 76.2% with 0.819 AUROC and onfidence interval :0.669-0.920.

CONCLUSION

Our initial experience suggests that elastography may be potentially useful for diagnosis of chronic inflammatory conditions of the major salivary glands. This conclusion needs to be further validated large sample studies.

Laryngological manifestations of Sjögren's syndrome

Sjögren’s syndrome (SS) is a systemic autoimmune disease characterized by lymphocytic infiltration of exocrine glands and a range of extra-glandular features. The most common and earliest symptoms are oral and ocular dryness. The aim of this study is to present the most common otolaryngological manifestations of SS, their pathomechanism and possible aetiology. The most common oral signs and symptoms are xerostomia, tooth decay, fungal infections, traumatic oral lesions, dysphagia, dysgeusia, and inflammation of the salivary glands. The salivary glands of SS patients are characterised by chronic inflammation. The presence of foci is thus a hallmark of SS. A biopsy can be taken from either the labial or the parotid salivary gland. The most significant complication of SS is the development of lymphoproliferative malignancy, which occurs in about 5% of SS patients. The ultrasonic greyscale scoring system, glandular volume measurement, and intraglandular power Doppler ultrasonography are specific ultrasound parameters of SS.

Ultrasound elastography in assessment of salivary glands involvement in primary Sjögren's syndrome

OBJECTIVE

Our study aimed to assess the pathological sonoelastographic changes in the major salivary glands and to demonstrate the diagnostic effectiveness of Sonoelastography as an additional method to US in Sjögren's syndrome.

METHODS

Fifty eight patients with primary Sjögren's syndrome (pSS) were selected according to the American-European Consensus Group Classification criteria. Twenty five healthy volunteers involved in this study. All patients were evaluated with B-mode and elastography by using Hitachi EUB 7500 digital ultrasound equipment. All subjects were female. The sonoelastography examination, which allowed us to assess the elasticity of the parenchyma, was performed and strain ratios were measured by comparing with the adjacent tissues.

RESULTS

Statistically significant differences were found between the pSS and control groups for the elastographic scores and strain ratios (p < 0.001). The highest sensitivity and specificity levels were obtained when the strain ratio cut-off value was taken as 1.55 for the submandibular gland and 2.45 for the parotid gland (sensitivity and specificity were 83% and 88% respectively for the submandibular gland and 83% and 92% respectively for the parotid gland). However, no statistically significant differences were found between the disease duration and the elasticity scores or strain ratios in pSS group (p > 0.05).

CONCLUSION

US examination is an efficient method to assess major salivary gland involvement in the diagnosis of pSS. Sonoelastography is a modality which can contribute to the diagnosis by improving specificity in the differential diagnosis of pSS. Strain ratio measurement, which is a semi-quantitative method, increases the diagnostic effectiveness by providing high sensitivity, specificity, and negative predictive values.

Elastographic ultrasound: an additional image tool in Sjögren's syndrome

AIM

To evaluate the stiffness of parotid and submandibular glands using elastography ultrasound and to correlate it with B-mode ultrasonographical, clinical and serological features, salivary profibrotic and inflammatory chemokines, and salivary gland fibrosis.

METHODS

We performed B-mode and elastography ultrasound of major salivary glands of 26 patients with primary Sjögren's syndrome. We registered the shear wave velocity (SWV) and correlated it with the morphologic ultrasonographic changes assessed by the Hocevar scale. We assessed the European League Against Rheumatism (EULAR) Sjögren's Syndrome Disease Activity Index (ESSDAI), EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI), non-stimulated whole salivary flow rate (NSWSF), C3 and C4 levels, anti-Ro/La antibodies, salivary inflammatory (C-X-C motif ligand 13 [CXCL13], CXCL10, CXCL8, C-C motif ligand 2 [CCL2], interleukin 10 [IL-10] and IL-6) and pro-fibrotic (CXCL14, CCL28, tumor necrosis factor-related apoptosis-inducing ligand and transforming growth factor β) chemokines and cytokines and evaluated the presence of fibrosis in the minor salivary gland.

RESULTS

Ninety-two percent of patients were women; mean age was 51.1 ± 11 years; median disease duration was 6.1 years; 92.3% had oral symptoms and 26.9% fibrosis. The median B-mode score was 22.2 points and the median SWV 2.5 m/s (τ = 0.53, P = 0.001). The SWV correlated with the NSWSF (τ = -0.53, P = 0.001), ESSDAI (τ = 0.31, P = 0.03), glandular ESDDAI domain (τ = 0.36, P = 0.02), C4 levels (τ = -0.32, P = 0.04), salivary CXCL13 (τ = 0.29, P = 0.03) and CXCL10 (τ = 0.30, P = 0.003), but not with age and fibrosis.

CONCLUSION

WV correlated with the B-mode ultrasound score, systemic and glandular activity and in a large degree with CXCL10, an inflammatory chemokine, but not with fibrosis. An increased SWV might represent chronic glandular inflammation rather than fibrotic changes in these patients.

Virtual Touch Quantification of the Salivary Glands for Diagnosis of Primary Sjögren Syndrome

OBJECTIVES

To investigate the value of salivary gland stiffness measured by Virtual Touch quantification (VTQ; Siemens Medical Solutions, Erlangen, Germany) for assessment of primary Sjögren syndrome.

METHODS

Fifty-four patients with primary Sjögren syndrome, 35 patients without primary Sjögren syndrome (patients with dry mouth and dry eye symptoms), and 52 healthy control volunteers were included in this study. Patients with primary Sjögren syndrome were classified as early or advanced stage by labial gland biopsies. All participants underwent B-mode sonography, on which the salivary glands (parotid and submandibular) were identified and VTQ measurements of shear wave velocity (SWV) were obtained. The diagnostic performance of SWV was evaluated by sensitivity and specificity at the optimum cutoff point and the area under the receiver operating characteristic curve.

RESULTS

For submandibular glands, the mean SWV ± SD values were 2.25 ± 0.34 m/s in patients with early-stage primary Sjögren, 1.84 ± 0.20 m/s in patients without primary Sjögren syndrome, and 1.82 ± 0.27 m/s in healthy controls (P< .001). With cutoff values of 2.15 and 2.10 m/s to separate patients with early-stage primary Sjögren syndrome from those without Sjögren syndrome and healthy controls, the sensitivity and specificity were 77.1% and 85.4% and 79.2% and 83.9%, respectively. For parotid glands, the SWV values were 2.78 ± 0.82 m/s in patients with early-stage primary Sjögren syndrome, 1.93 ± 0.33 m/s, in patients without primary Sjögren syndrome, and 1.85 ± 0.31 m/s in healthy controls (P < .001). With cutoff values of 2.18 and 2.10 m/s to separate patients with early-stage primary Sjögren syndrome from those without Sjögren syndrome and healthy controls, the sensitivity and specificity were 89.3 % and 75.3% and 91.4% and 80.0%.

CONCLUSIONS

The VTQ technique might be a useful noninvasive strategy for assessment of salivary glands in the early stage of primary Sjögren syndrome.

Ultrasonic Elastography Evaluation in Optic Neuritis

PURPOSE

In the present study, we attempted to determine whether ultrasonic elastography (USE) evaluation can be used in a diagnosis of optic neuritis (ON).

MATERIALS AND METHODS

Thirteen patients who each had one normal eye and one eye with a diagnosis of ON were included in the study. Ultrasonography (US) and USE examinations were performed on the affected and non-affected eyes of all participants. Optic nerve and adjacent fat tissue regions at the same depth were selected, and USE measurements were obtained. The optic nerve diameter was measured in both normal and affected eyes.

RESULTS

The mean USE values for the optic nerve were 2.58 ± 0.50 m/s in ON eyes and 1.91 ± 0.39 m/s in normal eyes (p = 0.001). The mean USE values for the optic-nerve adjacent tissue were 2.26 ± 0.45 m/s in ON eyes and 1.77 ± 0.22 m/s in normal eyes (p = 0.001). The mean optic-nerve diameter was 3.80 ± 1.09 mm in ON eyes and 3.28 ± 0.98 mm in normal eyes (p = 0.005).

CONCLUSIONS

USE may be considered an accessible, safe technique for the detection of significant optic-nerve tissue stiffness in ON and may be used an adjunctive tool for confirming this diagnosis.

Ultrasound Elastography for Distinction Between Parathyroid Adenomas and Thyroid Nodules

OBJECTIVES

The aim of this study was to detect the level of stiffness of parathyroid adenomas and to distinguish them from benign and malignant thyroid nodules using ultrasound elastography with acoustic radiation force impulse imaging.

METHODS

Twenty-one patients with parathyroid adenomas and 71 patients with thyroid nodules were evaluated by acoustic radiation force impulse imaging in this study. Acoustic radiation force impulse elastograms were obtained after evaluation of the thyroid nodules, which were predicted to undergo fine-needle aspiration biopsy, and patients with a diagnosis of hyperparathyroidism, which was identified by sonography at the same time.

RESULTS

An analysis of mean shear wave velocity (SWV) values for parathyroid adenomas and thyroid nodules showed that parathyroid adenomas had significantly higher stiffness levels compared to benign thyroid nodules (mean SWV ± SD, 3.09 ± 0.75 versus 2.20 ± 0.39 m/s; P < .001) and lower stiffness levels compared to malignant thyroid nodules (mean SWV, 3.09 ± 0.75 versus 3.59 ± 0.43 m/s; P < .001).

CONCLUSIONS

Acoustic radiation force impulse imaging has high sensitivity and specificity for differentiating parathyroid adenomas from benign and malignant thyroid nodules. As an adjunctive tool, it can help distinguish parathyroid adenomas from thyroid nodules, including posteriorly located nodules.

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.