Ultrasound of malignant cervical lymph nodes

Abstract

Malignant lymph nodes in the neck include metastases and lymphoma. Cervical nodal metastases are common in patients with head and neck cancers, and their assessment is important as it affects treatment planning and prognosis. Neck nodes are also a common site of lymphomatous involvement and an accurate diagnosis is essential as its treatment differs from other causes of neck lymphadenopathy. On ultrasound, grey scale sonography helps to evaluate nodal morphology, whilst power Doppler sonography is used to assess the vascular pattern. Grey scale sonographic features that help to identify metastatic and lymphomatous lymph nodes include size, shape and internal architecture (loss of hilar architecture, presence of intranodal necrosis and calcification). Soft tissue oedema and nodal matting are additional grey scale features seen in tuberculous nodes or in nodes that have been previously irradiated. Power Doppler sonography evaluates the vascular pattern of nodes and helps to identify the malignant nodes. In addition, serial monitoring of nodal size and vascularity are useful features in the assessment of treatment response.

Figure 1

Grey scale sonogram showing a metastatic lymph node which is enlarged, hypoechoic, well-defined and without an echogenic hilus (arrows).

Figure 2

Grey scale sonogram showing a metastatic lymph node from papillary carcinoma of the thyroid (arrows). Note the hyperechoic component within the node which may be related to intranodal deposition of thyroglobulin (arrowheads).

Figure 3

Longitudinal grey scale sonogram showing a metastatic cervical node (arrows) with intranodal cystic necrosis which appears ill-defined and echolucent (arrowheads).

Figure 4

Transverse grey scale sonogram of a metastatic lymph node from papillary carcinoma of the thyroid (arrows) with echogenic, punctate calcification (arrowheads).

Figure 5

Power Doppler sonogram of a metastatic lymph node with peripheral vascularity (arrowheads).

Figure 6

Spectral Doppler sonogram showing measurement of the resistive index (RI) and pulsatility index (PI) of a metastatic lymph node. Measurement of the peak systolic velocity (PSV) and end diastolic velocity (EDV) is also demonstrated. Note the measurements are obtained from three consecutive waveforms.

Figure 7

Grey scale sonogram showing multiple hypoechoic lymphomatous nodes. Arrowheads indicate the intranodal reticulation, commonly seen in lymphomatous nodes using high-resolution transducers.

Figure 8

Directional power Doppler sonogram showing a lymphomatous lymph node with both hilar (arrows) and peripheral (arrowheads) vascularity, which are commonly seen in lymphoma.

Figure 9

Grey scale ultrasound images of a lymphomatous cervical lymph node at the start (top) and at peak enhancement (bottom) of contrast administration. The lymph node parenchyma enhances uniformly with contrast. A region of interest is drawn to include the lymph node to calculate a time-enhancement curve.

Figure 10

Grey scale ultrasound images of the same lymph node (as in Fig. 9) after chemotherapy, at the start (top) and at peak enhancement (bottom) of contrast administration. The lymph node is smaller in size, the parenchyma enhances less (lower peak enhancement) and enhancement is more heterogeneous.

Figure 11

Dynamic time-enhancement curves before (top) and after chemotherapy (bottom) for the same affected cervical lymph node as in Figs. 9 and 10. The time to peak contrast enhancement has lengthened from 34.9 s to 44.8 s. The peak and total (area under curve) contrast enhancement are both lower after treatment.