Ultrasonography

Ultrasonography is used to evaluate superficial lesions, lymph nodes and to guide needle aspiration biopsies (NAB). NAB is used in order to confirm metastatic lymph nodes. Chaukar et al. reported that ultrasonography is insufficient as a stand-alone method for evaluating cervical lymph nodes (sensitivity 79%, specificity 69%) [17].

In oral cancer, intraoral USG with color-Doppler can also be used in order to assess the involvement of lymph nodes. It can show an increased vascularity within the tumor (blood flow), microvascular changes, size of the lesion and its thickness and the distance between mucous membrane and the front of the tumor [44]. The formation of new vessels can have a prognostic value [45,46]. Intrapapillary capillary loops of the mucous membrane have been recently studied with narrow-band imaging. This helps localize lesions of the mucous membrane and therefore early stages of cancer. However, it cannot detect lesions beyond mucous membrane [47].

Ultrasound imaging can be helpful is assessing lymph nodes following a radical surgical resection with or without adjuvant radiation therapy. According to Wu-Chia et al., ultrasound-guided fine needle aspiration (UsFNA) results in an improved assessment of disease recurrence in lymph nodes. Moreover, they showed that secondary lesions not exposed to radiation therapy had a lower frequency of calcification than lymph nodes treated with radiation. Radiotherapy has an effect on image of the classical ultrasound, however, it does not limit UsFNA [48].