膵の囊胞性疾患の診断―USを中心に

Ultrasound in Its Use for the Diagnosis of Cysts of the Pancreas

要旨　超音波検査は卓越した簡便性と描出能を持ち，膵囊胞性疾患の臨床に欠くことのできない診断法となってきた。実質性腫瘤との鑑別をはじめ，従来，診断困難であった小さな囊胞の見つけ出し，仮性囊胞や腫瘍性囊胞の質的診断などに役立つ検査法である．膵囊胞の大部分は仮性囊胞ないし貯留囊胞であるが，腫瘍性囊胞の鑑別は臨床的に重要な問題である．そこで，臨床的な立場から腫瘍性囊胞と非腫瘍性囊胞に大きく分け，腫瘍性囊胞においては，質的診断に有用な特徴的所見について，また，非腫瘍性囊胞においては，病態診断や原因診断を中心に超音波診断の有用性を述べた．また，超音波映像下に行われる経皮的穿刺は診断ばかりでなく，最近，仮性嚢胞の治療にも応用される．経皮的穿刺吸引法あるいはドレナージ法の急性期仮性囊胞における治療上の有用性を示し，適応について考察を加えた．

　Ultrasound, because of the simplicity of its use, and the excellent results obtained in practice for detecting tissue-quality differences, has become an indispensable means for the diagnosis of cysts of the pancreas. Besides the differentiation of cysts from solid tumors, it is useful in various aspects of clinical diagnosis, for instance, in the detection of small cysts which are hardly detectable by usual means, in the as-sessment of conditions of pseudocysts, in the manage-ment and the differentiation of neoplastic cysts from others. Cysts of the pancreas are mostly pseudocysts and retention cysts. Although neoplastic cysts are rare, it is clinically important to differentiate them accurately. In this article, ultrasound of neoplastic and non-neoplastic cysts is discussed from practical view points. The characteristic findings about neo-plastic cysts were stressed. Concerning non-neoplastic cysts, mostly pseudocysts, ultrasound was shown to be useful in demonstrating their morbid conditions and clarifying causative lesions.

　Recently, puncture technique performed during actual ultrasound monitoring has been applied not only to the diagnosis but also to the treatment of pseudocysts. Based on our results, percutaneous aspiration and drainage can be said to be useful for the treatment of acute pseudocysts with the rate of their resolution as high as 79%. Points indicated by our practical findings are discussed.