Grey-scale sonography in assessment of cervical lymphadenopathy: review of sonographic appearances and features that may help a beginner.

Ultrasound examinations of the neck in 218 patients with confirmed cervical lymphadenopathy were reviewed. Lymph nodes were assessed for their size, shape, internal architecture, echogenicity, nodal border, posterior enhancement, and ancillary features (adjacent soft tissues oedema, and matting). The hilus is a linear, echogenic, non-shadowing structure containing nodal vessels, and is continuous with fat around the node. Coagulation necrosis is an ill-defined, rounded, non-shadowing echogenic area within a node. It is less echogenic than the hilus and is not continuous with the fat around the node. Calcification is a highly echogenic focus within the node, which may be dense or punctate echogenic foci. It is not continuous with the fat around the node. Dense intranodal calcification usually produces shadowing. However, fine punctate calcification may not have posterior shadowing though, if the transducer frequency is increased, it may show thin lines. Cystic necrosis is focal, often ill-defined echolucent area within the node. Echogenicity of lymph nodes is usually compared with the adjacent muscles, and is classified as hypoechogenicity, isoechogenicity, and hyperechogenicity. The nodal border is assessed for its sharpness. Posterior enhancement is when the structures posterior to the node look more echogenic than neighbouring areas. Oedema of soft tissues is an ill-defined, hypoechoic area around the node with loss of adjacent fascial planes. Nodes are considered matted when they are clumped or adherent to each other with no normal intervening soft tissue between them. Ultrasound features that help only in identifying abnormal nodes include size, shape, echogenic hilus, hypoechogenicity or isoechogenicity, echogeneity, coagulation necrosis, and a sharp nodal border. Ultrasound features that help to identify abnormal nodes as well as giving clues to the primary lesion include hyperechogenicity, intranodal calcification, intranodal cystic necrosis, ragged nodal border, posterior enhancement, adjacent soft tissue oedema, and matting.