Imaging of cervical lymphadenopathy.

Imaging of the neck is important to diagnose occult lesions and stage the neck in cancer patients and, to a lesser extent, help differentiate swellings in the neck. Furthermore, extension of tumors can be depicted, although assessment of operability is not very reliable. Conventional imaging techniques, such as CT, MR imaging, and US, are rapidly evolving by improvement of spatial resolution and contrast, reduction of artifacts, and development of new contrast agents. Unreliable criteria for metastases, such as size and shape, will be replaced in the future by the depiction of the microstructure inside lymph nodes and the development of specific contrast agents. US-guided aspiration is currently one of the most accurate techniques to assess occult metastases as it overcomes the criteria used by CT, MR imaging, or US without aspiration. It should be noted, however, that approximately 25% of electively operated sides of the neck contain exclusively metastases smaller than 3 mm, limiting the sensitivity in these necks to 75% for all imaging modalities. New imaging modalities, such as immunoimaging with SPECT, thallium SPECT, PET, and fused images, are rapidly developing. Although these techniques will probably become very accurate for the staging of the neck, it is doubtful whether they will be used routinely to stage the neck because of the issues of cost and availability. Their role will probably be more in the detection of unknown primaries, distant metastases, and follow-up, after radiotherapy in case of clinical doubt.