Ultrasound findings requiring special attention in head and neck

Abstract

Cervical cystic disease or peritracheal tumors can be difficult to differentiate on ultrasound of the head and neck. Cervical cystic diseases include congenital cystic lesions and tuberculosis. Lymph node metastasis of papillary thyroid carcinoma and human papillomavirus-related oropharyngeal carcinoma should be considered in the differential diagnosis. Appropriate diagnosis and treatment are required because target ages and treatment methods are different. The characteristics of each disease and the tests necessary for differentiation are herein described. Peritracheal mass lesions include various diseases such as thyroid tumors, parathyroid tumors, paratracheal lymph node metastasis, and schwannoma. Since many structures are densely packed in a narrow area, it is often difficult to distinguish them using only ultrasonography. It is necessary to comprehensively judge clinical findings, various imaging examinations, and pathological examinations to make the differential diagnosis. Use of chemoradiotherapy, which is one form of curative treatment for head and neck cancer, is increasing in recent years. Ultrasonography is also useful for evaluating the response to chemoradiotherapy for cervical lymph node metastasis. Degeneration after treatment occurs gradually over 8 to 16 weeks, so it is important to continue monitoring the patient. Reduction in lymph node size, changes in echogenicity, and disappearance of fluid and blood flow components are observed after treatment. Ultrasonography can be used to observe qualitative changes in lymph nodes that cannot be visualized with CT or MRI. By combining ultrasonography with other imaging examinations, it may be possible to assess the response to treatment with higher accuracy.