Sonoelastography techniques in the evaluation and diagnosis of parotid neoplasms

Abstract

Ultrasound is the first-line imaging investigation in the evaluation of parotid gland lesions; however, ultrasound alone cannot differentiate between benign and malignant lesions. An imaging technique with this capability would be of great value, as fine needle aspiration cytology (FNAC) is not always accurate and partial/total parotidectomy is associated with facial nerve palsy and Frey's syndrome. Sonoelastography is a novel imaging technique that has been employed in the research setting in the evaluation of tissues including breast, thyroid, prostate and the salivary glands. More recently it has been used as a diagnostic adjunct in the sonographic evaluation of major salivary gland lesions. This review article outlines the current role of sonoelastography in the diagnostic imaging of parotid lesions, with particular reference to the findings of two research papers published in European Radiology. These papers employ slightly different techniques: the first utilises shear wave elastography whilst the second uses real-time sonoelastography. Sonoelastography may have potential as a diagnostic imaging adjunct to conventional ultrasound. However, it seems likely that FNAC/core biopsy will continue to be necessary. Further studies to evaluate the reproducibility of sonoelastographic results across a range of operators and systems are also needed. Key Points • Ultrasound is the initial and often definitive investigation for parotid lesions • Ultrasound-based strain elastography has been attempted but offered little additional information • New shear wave elastographic techniques did not confer much advantage either • However, analysis of elastographic patterns seems to provide advantages over ultrasound alone.

Real-Time Tissue Elastography as Promising Diagnostic Tool for Diagnosis of Lymph Node Metastases in Patients with Malignant Melanoma: A Prospective Single-Center Experience

“…The results of the tissue compression are displayed as an image called elastogram with color-coded tissue appearing on the strain image as red, yellow, green and blue in ascending order of tissue hardness. The color code is freely selectable and was chosen in our study according to former investigations about the differentiation between benign and malignant lesions in the above-mentioned organs [8,9,10,11,12,13,14,15]. Similar to findings in solid tumors, elasticity may be one of the differentiating criteria for metastatic and reactive LNs according to the hypothesis that tumor cells differ in their consistency from adjacent normal tissue.…”

“…The term ‘elastography' was first mentioned about 20 years ago by Ophir et al [7] to define an imaging technique that conveyed information about a tissue's relative firmness in response to compression. Meanwhile, this technique has been successfully introduced in the evaluation of various tissues including breast, thyroid, prostate and the salivary glands, particularly concerning the differentiation between benign and malignant tumors [8,9,10,11,12,13,14,15]. Elastography is based on the principle that softer tissue deforms more easily than harder tissue when light compression is performed by manual freehand operation [7].…”

Sonoelastographic Modalities in the Evaluation of Salivary Gland Characteristics in Sjögren's Syndrome

“…During the past few years, there has been a major improvement in ultrasonographic modalities such as real-time tissue elastography (RTTE), Virtual Touch imaging (VTI) and Virtual Touch quantification (VTQ), enabling the provision of qualitative and quantitative information on the mechanical stiffness of the examined tissue or region (Benson and Fan 2012;Bhatia et al 2010Bhatia et al , 2012Westerland and Howlett 2012). These new modalities could find their way into the daily clinic routine for various indications in several clinical specialties and, meanwhile, are part of the assessment of the thyroid gland or mammary lesions (Wojcinski et al 2013;Zhang et al 2015).…”

ARFI quantitative elastography of the submandibular glands. Normal measurements and the diagnosis value of the method in radiation submaxillitis

“…Color-coded static elastographic procedures have a global disadvantage of being semiquantitative. They first emphasize the tumoral masses when these have different stiffness from that of the surrounding parenchyma [11]. The information provided through color-coded procedures regarding the submandibular parenchyma in diffuse conditions is discouraged as it is considered just guiding and highly subjective [12].…”