Role of Sonoelastography for Differentiating Benign and Malignant Cervical Lymph Nodes: A Cross-sectional Study

Abstract

Introduction: Cervical nodes form one of the major groups of Lymph Nodes (LN) that are frequently involved in inflammatory and neoplastic diseases. Metastasis causes the most apparent change in consistency of the node among the various nodal pathologies. Ultrasound elastography provides an estimate of tissue consistency by measuring the degree of distortion under the application of an external force. Aim: To estimate the diagnostic accuracy of sonoelastography in the differentiation of malignant and benign cervical LN with Fine Needle Aspiration Cytology (FNAC)/biopsy considered as a gold standard. Materials and Methods: A cross-sectional study was carried out from March 2020 to January 2021 in a tertiary care hospital in south India, a total of 50 patients with cervical lymphadenopathy underwent ultrasonography followed by elastography of superficial neck LN using high frequency linear transducer by freehand technique. The ultrasound characteristics of selected LN were determined and colour elastogram pattern was assessed using colour mapping elastography. The Chi-square test was performed. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were obtained. The results were then compared to the fine needle aspiration cytology. Results: A total of 50 subjects (median age of 40.5±18.71 years; 19 (38%) males and 31 (62%) females). The grayscale and colour Doppler features of cervical LN which helped predict malignancy were short axis ≥8 mm, Short:Long axis diameter ratio (S:L) ≥0.5, absence of normal central fatty hilum, abnormal echogenicity, lobulated border, presence of calcification and peripheral/mixed vascularity. With reference to the above variables of cervical LN characterisation on grayscale, colour doppler ultrasound and sonoelastography findings, elastography pattern was the most promising variable to differentiate malignant from benign cervical LN with 95.2% sensitivity, 75.0% specificity, 95.2% PPV, 75.0% NPV and 92.0% accuracy. Conclusion: Sonoelastography is useful in the assessment of elastic properties of cervical LN with short examination time required, real-time display, immediate interpretation and limited cost. Sonoelastography had higher diagnostic accuracy than gray scale and doppler ultrasound in differentiating benign from malignant cervical LN. Sonoelastography is an effective supplement to conventional gray scale and colour doppler ultrasound and that the combination is clinically recommended for a more accurate diagnosis of metastatic LN.

Keywords

• colour elastogram pattern
• colour doppler
• elastography