福原 隆宏

Takahiro FUKUHARA

鳥取大学医学部感覚運動医学講座耳鼻咽喉・頭頸部外科学分野

Department of Otolaryngology, Head and Neck Surgery, Tottori University Faculty of Medicine

キーワード : cervical ultrasonography, cervical lymph node, metastatic lymph node, head and neck cancer, elastography

頭頸部領域で使用する高周波リニアプローブの分解能は高く細かな構造まで観察可能であり，頭頸部領域での超音波検査の有用性は高い．ただし，頸部は解剖が複雑であるため，頸部の超音波評価のためには，まず解剖を理解する必要がある．頸部は複数の筋膜が重なった構造をしており，深頸筋膜浅葉と深葉に挟まれた層に血管や深頸リンパ節の流れがある．頸部リンパ節腫脹や腫瘤の多くはこの層に存在するため，頸部超音波検査ではここを中心に観察する．リンパ節の良悪性を判定する場合，リンパ節の内部構造をBモードとドプラで観察する．癌腫によって特徴的な超音波像を示すものもあり，原発の予測にも役立つ．良性のリンパ節腫脹の中でも結核性リンパ節炎はその鑑別が難しく，診断が困難なため注意を要する．頭頸部癌は原発部位によって転移や再発の様式が異なる．さらに頭頸部癌術後の頸部再発のフォローのための超音波検査は，手術で頸部の解剖が大きく変わっているため注意を要する．手術記録や術前の超音波検査所見などの診療情報が役に立つ．以上の内容について本文で詳しく解説をおこなった．

High-frequency linear probes used in the head and neck region have high resolution and can observe fine structures. Therefore, ultrasonography in the head and neck region is highly useful. However, the anatomy of the neck is complex, and it is necessary to understand the anatomy of the neck for ultrasound evaluation. The neck is composed of multiple overlapping fascia, and blood vessels and cervical lymph node flow are in the layer between the shallow and deep lobes of the deep cervical fascia. Since most cervical lymphadenopathies and masses are located in this layer, the examiner should focus on this area during cervical ultrasonography. When determining whether a lymph node is benign or malignant, the internal structures of the lymph node are assessed using B-mode and Doppler ultrasound. Some metastatic lymph nodes show characteristic ultrasound images depending on the carcinoma, which is also helpful in predicting the primary site. Among benign lymphadenopathies, tuberculous lymphadenitis requires attention because it is difficult to distinguish and diagnose. The mode of metastasis or recurrence of head and neck cancer differs depending on the primary site. Furthermore, ultrasonography for follow-up of cervical recurrence after head and neck surgery should be performed with caution because the anatomy of the neck has changed significantly after surgery. Medical information such as surgical records and preoperative ultrasound findings can be helpful. These topics are discussed in detail in this text.