Ultrasound Elastography for the Evaluation of Lymph Nodes.

Bin Wang,Yang Yu,Xin-Wu Cui,Qi Guo,Jia-Yu Wang,Ai-Jiao Yi,Christoph F Dietrich

doi:10.3389/fonc.2021.714660

Abstract

The differential diagnosis of lymphadenopathy is important for predicting prognosis, staging, and monitoring the treatment, especially for cancer patients. Conventional computed tomography and magnetic resonance imaging characterize lymph node (LN) with disappointing sensitivity and specificity. Conventional ultrasound with the advantage of high resolution has been widely used for the LN evaluation. Ultrasound elastography (UE) using color map or shear wave velocity can non-invasively demonstrate the stiffness and homogeneity of both the cortex and medulla of LNs and can detect early circumscribed malignant infiltration. There is a need of a review to comprehensively discuss the current knowledge of the applications of various UE techniques in the evaluation of LNs. In this review, we discussed the principles of strain elastography and shear wave-based elastography, and their advantages and limitations in the evaluation of LNs. In addition, we comprehensively introduced the applications of various UE techniques in the differential diagnosis of reactive LNs, lymphoma, metastatic LNs, and other lymphadenopathy. Moreover, the applications of endoscopic UE and endobronchial UE are also discussed, including their use for improving the positive rate of diagnosis of fine-needle aspiration biopsy.

Highlights

Various benign and malignant disorders can result in lymphadenopathy; the differential diagnosis of lymph node (LN) is important for predicting prognosis, staging, and monitoring the treatment
This review aims to comprehensively discuss the current knowledge of the applications of various Ultrasound elastography (UE) techniques in the evaluation of LNs
UE is a promising method for measuring tissue hardness and has been widely used in differentiating reactive LNs, lymphoma, metastatic LNs, and other lymphadenopathy

Summary

Introduction

Various benign and malignant disorders can result in lymphadenopathy; the differential diagnosis of lymph node (LN) is important for predicting prognosis, staging, and monitoring the treatment. Conventional computed tomography (CT) and magnetic resonance imaging (MRI) characterize LN relying on size and topographic distribution, but with disappointing sensitivity and specificity, since it is not rare that malignant LN infiltration occurs in normal-sized LN. Conventional ultrasound (US) with the advantage of high resolution has been widely used for imaging superficial organs, for the LN evaluation. Compared with conventional CT and MRI, B-mode US can provide more detailed information on shape, contour, inner texture, maximum short axis diameter, long to short axis ratio, absence of hilus, and presence of necrosis. Color Doppler US and spectral Doppler US can image the hemodynamic characters of LN and add values for the differentiation of malignant from benign LNs. Benign LNs often show hilar predominant vessel

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