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 Table of Contents  
Year : 2022  |  Volume : 17  |  Issue : 3  |  Page : 632-636

Sonoelastographic characterization of parotid and submandibular lesions our initial experience: A prospective observational study

Department of Radio-Diagnosis, DMIMS, Jawaharlal Nehru Medical College, Wardha, Maharashtra, India

Date of Submission30-Nov-2020
Date of Decision31-Mar-2021
Date of Acceptance18-Jul-2021
Date of Web Publication2-Nov-2022

Correspondence Address:
Dr. Suresh V Phatak
Department of Radio-Diagnosis, DMIMS, Jawaharlal Nehru Medical College, Sawangi, Wardha - 442 001, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jdmimsu.jdmimsu_419_20

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Context: Sonoelastography is an emerging noninvasive imaging modality used for the assessment of soft tissue lesions. Parotid and submandibular glands are relatively superficial structures which can be easily assessed and examined to characterize the lesions. Aim: The aim of the present study is to evaluate the sonoelastographic features of various benign and malignant parotid and submandibular gland lesions, and correlate their findings with pathology. Materials and Methods: In a prospective observational study conducted in Acharya Vinoba Bhave Rural Hospital of JNMC College, Sawangi, Wardha, 24 patients who presented with salivary gland lesions were evaluated with sonoelastography during 2 years. Results: The most common age group in this study was 51–60 years, followed by 31–40 years. Benign lesions were more common than malignant ones. Higher values of strain ratio were seen in cases of malignant tumours correlating well with score of 3 and 4 on elastography. Conclusions: Sonoelastography is a recent advance in ultrasound for the evaluation of salivary gland lesions showing good correlation with pathology so it can be employed routinely in presurgical evaluation.

Keywords: Parotid tumors, sonoelastography, submandibular gland

How to cite this article:
Manoj M, Phatak SV, Harshith Gowda K B, Ghanta P, Jain S, Gupta R. Sonoelastographic characterization of parotid and submandibular lesions our initial experience: A prospective observational study. J Datta Meghe Inst Med Sci Univ 2022;17:632-6

How to cite this URL:
Manoj M, Phatak SV, Harshith Gowda K B, Ghanta P, Jain S, Gupta R. Sonoelastographic characterization of parotid and submandibular lesions our initial experience: A prospective observational study. J Datta Meghe Inst Med Sci Univ [serial online] 2022 [cited 2023 Feb 8];17:632-6. Available from: http://www.journaldmims.com/text.asp?2022/17/3/632/360222

  Introduction Top

The parotid gland is the largest salivary gland out of the three major salivary glands. Unlike the other two glands, it is a serous gland, situated in the retro-mandibular region. The submandibular gland is a triangular shaped mixed type of salivary gland situated in the submandibular triangle.

Out of the three major salivary glands in our body, parotid and salivary glands can be assessed using sonography because of their relatively superficial location. On high-resolution sonography, salivary gland appears as uniformly hyperechoic structure in comparison to the surrounding musculature. The amount of intra-glandular fat determines the echogenicity of the glands.[1] Parotid gland has two parts-superficial and deep, separated by the facial nerve and its branches. On sonography, the facial nerve is not always readily visualized. Therefore, retro-mandibular vein, which is formed by the union of temporomaxillary and posterior facial vein, is used as the landmark to differentiate the two lobes. The deep parotid lobe, owing its location, can only be visualized partially.

Salivary gland disorders are relatively uncommon disorders, ranging from developmental to neoplastic conditions. Out of these, inflammatory lesions are the most common. The incidence of salivary gland tumors varies with the community, their environment, and other factors like occupational exposures. The overall prevalence of these lesions varies between 3% and 6% of all the head and neck tumors.[2] In Central India, the incidence of neoplastic lesions was found to be 2.77% of all the lesions involving salivary glands.[3] In general, the aggressiveness of salivary gland tumors depends on the size of the gland i.e., benign lesions tend to be more common in parotid glands than the other two. Parotid glands are the most commonly affected glands and the most common benign neoplasm affecting parotid gland is Pleomorphic adenoma, accounting for 70%–80%. Overall, Mucoepidermoid carcinoma and adenoid cystic carcinoma are the most common malignant tumors affecting the salivary glands. These tumors can exhibit perineural spread and distant metastases to lungs, bones and soft tissue.[4]

Most salivary gland tumors present as asymptomatic swelling near the jaw, neck or mouth. Sometimes they can present with nonspecific symptoms like facial nerve palsy or lymphadenopathy. These tumors can grow rapidly in size and attain large sizes weighing several kilograms depending on the aggressiveness of the lesion.[5]

The gold standard in diagnosis of salivary gland tumors is fine-needle aspiration cytology, although its sensitivity and specificity varies widely. It ranges from 57% to 98% and 56% to 100% respectively, with accuracy ranging from 78% to 98%.[6],[7] Due to its relatively low sensitivity and specificity, preoperative imaging plays a pivotal role in further management of these lesions.

The treatment of choice for benign lesions is local excision or partial removal of the gland whereas for malignant lesions, surgical removal of the entire gland followed by adjuvant therapy has to be done.[4]

The main noninvasive imaging modalities include sonography, computed tomography (CT), and Magnetic resonance imaging (MRI). An initial evaluation using sonography is usually followed by CT or MRI evaluation. Ultrasonography (USG) with elastography can be very valuable in differentiating benign and malignant salivary gland neoplasms.

At present, the data regarding the use of sonoelastography in the assessment of parotid gland lesions is limited. The aim of the present study is to evaluate the sonoelastographic features of various benign and malignant parotid and submandibular gland lesions, and correlate their findings with pathology.

  Materials and Methods Top

A prospective observational study of patients presenting with clinically suspected salivary gland masses was conducted at Radio-diagnosis Department, AVBRH Jawaharlal Nehru medical college Sawangi Maharashtra. A total of 24 subjects were included in the study which was done from December 2016 to December 2018, 24 salivary gland masses were examined. Eighteen patients were female and six patients were male. The inclusion criterion was a palpable mass that was located within a salivary gland on ultrasound. Exclusion criteria were postoperative cases and patients with known histopathology reports. In addition, images of isolated intra-parotid lymph nodes of normal shape and size were excluded from analysis. The gold standard for diagnosis was pathological correlation.

Both the parotid and submandibular glands were evaluated in supine position with the patient's neck hyper-extended using a linear transducer (12–18 MHz frequency) in a high-end ultrasound machine, Hitachi Aloka Arietta S70 with strain elastography [Table 1], [Table 2], [Table 3], [Table 4].
Table 1: Pathological diagnosis of lesions

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Table 2: Distribution of benign lesions

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Table 3: Elastography score of various lesions

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Table 4: Comparison of sonoelastographic diagnosis with pathology (gold standard)

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The entire gland was evaluated in orthogonal planes and echogenicity, echotexture, shape, margins, size, and presence of calcifications or cystic components within the lesion were noted. The whole neck including the contra-lateral gland was also evaluated for enlarged lymph nodes. Grey-scale and sonoelastography images of all the cases were obtained. Grayscale imaging was followed by Doppler study and Elastography to characterize the vascularity and tissue composition of the lesion, respectively. A 4-point elastography scoring system developed by Itoh et al. was used to categorize the lesions. According to this scoring system, Score 1 was given to lesions which showed similar mixture of green, yellow and red areas to the surrounding. Lesions with <50% of blue was given a Score of 2, >50% blue was 3 and entirely blue was 4. Score 3 and 4 were considered to be malignant lesions.[8]

  Ethical clearance Top

The Institutional Ethics Committee of DMIMSDU has approved the Research work proposed to be carried out at Jawaharlal Nehru Medical College, Sawangi(M), Wardha. Date : 16th Feb 2019 with Reference no DMIMS(DU)/IEC/2019-20/44.

  Results Top

Out of the 24 patients who underwent radiological and pathological evaluation, 18 were female and 6 were male, and the mean age was found to be 52.5 years (range 27–61 years). Most of the cases where in the age group of 51–60 years, followed by 31–40 and 41–50 years.

Out of the 19 benign lesions found, 47.3% was pleomorphic adenoma, 26.3% was sialadenitis, 15.7% was Warthin's tumor and 10.5% was abscess.

On elastography, the average strain ratio of benign and malignant lesions was found to be 1.75 ± 0.45 and 3.78 ± 0.51 respectively. Based on sonoelastography scoring, lesions were classified as Score 1 for 5 lesions, Score 2 for 15, Score 3 for 2, and Score 4 was assigned to another 2 lesions.

On imaging and pathological correlation, sonoelastographic findings of 22 cases were found to be consistent with the final pathological report whereas 2 cases were found to be inconsistent. Two lesions which were falsely diagnosed as benign lesions on sonoelastography turned out to be malignant lesions on pathology [Figure 1], [Figure 2], [Figure 3], [Figure 4] and [Chart 1] and [Chart 2].
Figure 1: Ultrasonography of parotid gland shows an ill-defined hypoechoic lesion in the superficial lobe. Sonoelastography shows >50% of blue colour (Score 3) and a strain ratio of 3.83, indicating a malignant nature of the lesion, later on confirmed to be a case of Mucoepidermoid carcinoma

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Figure 2: Ultrasonography of parotid gland shows an ill-defined hypoechoic lesion in the superficial lobe. Sonoelastography shows <50% of blue colour (Score 2) and a strain ratio of 1.55, indicating a benign nature of the lesion, later on confirmed to be a case of Pleomorphic adenoma

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Figure 3: (a) Ultrasonography of parotid gland shows a well-defined hypoechoic lesion with cystic component in central part, low-level internal echoes and septation in the parotid gland. (b) Sonoelastography shows blue-green-red pattern in central part, indicating a cystic nature of the lesion, later on confirmed to be a case of Parotid abscess

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Figure 4: (a) Ultrasonography of parotid gland shows diffuse hypoechogenecity in the parotid gland. (b) Sonoelastography shows a similar blue, green and red pattern to the surrounding tissue (Score 1), indicating a benign nature of the lesion, later on confirmed to be a case of Sialadenitis

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  Discussion Top

Pleomorphic adenoma and Warthin's tumors are the most common benign neoplasms affecting the major salivary glands. Clinically, these tumors present as asymptomatic lesions which are often diagnosed incidentally, or as slow-growing painless masses. On USG, benign lesions typically present as well-defined hypoechoic lobulated lesions with or without anechoic areas within. Warthin's tumor often exhibit hypervascularity compared to Pleomorphic adenomas which show poor vascularity on Doppler. Other benign tumors such as oncocytoma, basal cell adenoma, hemangioma, lipoma, and schwannoma are encountered less frequently. Mucoepidermoid carcinoma and adenoid cystic carcinoma are the two most common malignant neoplasms involving major salivary glands.[9] Other lesions squamous cell carcinoma, acinic cell carcinoma and adenocarcinoma are uncommon. Malignant lesions are more common in submandibular than parotid gland. These neoplasms exhibit rapid growth and local invasion as well as local and distal metastasis. Although distal metastasis is relatively rare. On sonography, these lesions typically present as ill-defined heterogeneous lesions with high vascularity on Doppler. Malignant lesions can also sometimes present as well-defined homogeneous lesions or as cystic lesions with intramural nodules.[10],[11] Increased vascularity on Doppler of these lesions is not a pathognomic finding as it can also be seen in benign conditions like Warthin's tumor.[12] Whereas presence of enlarged necrotic lymph nodes along with a mass strongly suggests possibility of malignancy.

Other nonneoplastic lesions like abscess and inflammation can also present with swelling of the gland. On sonography examination, abscess appears as hypoechoic to anechoic collections with posterior acoustic shadowing, internal low level echoes and septations. These lesions typically show peripheral vascularity on Doppler. Acute inflammation of the gland presents as diffusely enlarged hypoechoic gland with increased vascularity on Doppler. Both the lesions can be associated with reactive lymphadenopathy.

Elastography is a novel imaging technology which allows us to determine the stiffness of tissue under evaluation. There are two basic types of imaging technique: Strain and shear wave imaging. In strain imaging, a manual compressive force is applied on the lesion by the transducer and strain measurements are displayed as a semitransparent colour map, which overlaps B-mode image. Typically, stiff tissue is displayed in blue whereas a soft tissue is displayed in red, although the color scale can differ. However, cystic lesions show a distinct (blue-green-red) pattern on sonoelastography. Strain ratio is calculated as a ratio of stiffness of region of interest in lesion to region of interest of normal tissue. Whereas in shear wave imaging, a dynamic stress is created, this measures both qualitative and quantitative elasticity of the tissue.[13] This study was done using strain elastography imaging.

In a similar study done by Dumitriu et al. in 2011, 66 subjects were included. Sonoelastography parameters were recorded. The mean elastography score of benign and malignant lesions was found to be 2.41 ± 0.87 and 2.94 ± 0.87, respectively. Based on their sonoelastographic scoring system, 8 lesions were assigned Score 1, 29 Score 2, 26 Score 3 and 11 Score 4.[14]

In our study, the mean strain ratio of benign and malignant lesions was 1.75 ± 0.45 and 3.78 ± 0.51, respectively. Higher strain ratios are usually associated with malignancy. Based on sonoelastographic scoring system, benign lesions showed Score 1 and 2 whereas malignant lesion showed Score 3 and 4.

  Conclusions Top

High-resolution USG is used as the primary imaging modality for the evaluation of salivary glands as it is the most readily available and affordable modality. Other advantages like lack of ionizing radiation and dynamic imaging make it an ideal screening modality. The disadvantages of USG in imaging salivary glands are its inability to visualize deeper structures, assess extend of the lesion, and operator dependency. But in experienced hands, USG can be quite valuable in evaluating various pathologies of salivary glands. Efficient evaluation of these glands by USG would allow us to differentiate the lesions as nonneoplastic and neoplastic, thereby avoiding unnecessary biopsies. Elastography can greatly improve the diagnostic accuracy of USG and differentiate benign and malignant lesions from each other. In this prospective observational study, sonoelastographic findings of most of the salivary gland lesions correlated with the pathological diagnosis, which is considered to be the gold standard indicating its diagnostic value and future prospects in presurgical diagnosis and staging, helping in patient management.


The limitation of this study was small sample size. Findings of this study need to be verified with a large series of patients.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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Araya J, Martinez R, Niklander S, Marshall M, Esguep A. Incidence and prevalence of salivary gland tumours in Valparaiso, Chile. Med Oral Patol Oral Cir Bucal 2015;20:e532-9.  Back to cited text no. 2
Sardar MA, Ganvir SM, Hazarey VK. A demographic study of salivary gland tumors. SRM J Res Dent Sci 2018;9:67.  Back to cited text no. 3
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Das DK, Petkar MA, Al-Mane NM, Sheikh ZA, Mallik MK, Anim JT. Role of fine needle aspiration cytology in the diagnosis of swellings in the salivary gland regions: A study of 712 cases. Med Princ Pract 2004;13:95-106.  Back to cited text no. 7
Itoh A, Ueno E, Tohno E, Kamma H, Takahashi H, Shiina T, et al. Breast disease: Clinical application of US elastography for diagnosis. Radiology 2006;239:341-50.  Back to cited text no. 8
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Howlett DC. High resolution ultrasound assessment of the parotid gland. Br J Radiol 2003;76:271-7.  Back to cited text no. 11
Schick S, Steiner E, Gahleitner A, Böhm P, Helbich T, Ba-Ssalamah A, et al. Differentiation of benign and malignant tumors of the parotid gland: Value of pulsed Doppler and color Doppler sonography. Eur Radiol 1998;8:1462-7.  Back to cited text no. 12
Sigrist RM, Liau J, El Kaffas A, Chammas MC, Willmann JK. Ultrasound elastography: Review of techniques and clinical applications. Theranostics 2017;7:1303.  Back to cited text no. 13
Dumitriu D, Dudea S, Botar-Jid C, Baciut M, Baciut G. Real-time sonoelastography of major salivary gland tumors. Am J Roentgenol 2011;197:W924-30.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1], [Table 2], [Table 3], [Table 4]


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