田中 弘教

Hironori TANAKA

宝塚市立病院消化器内科

Department of Gastroenterology and Hepatology, Takarazuka Municipal Hospital

キーワード : hepatocellular carcinoma, ultrasound, contrast-enhanced ultrasound, Sonazoid, fusion

超音波検査（US）は，安価で，非侵襲的に肝細胞癌（HCC）をリアルタイムに検出できるため，代表的かつ普遍的な肝癌サーベイランス方法である．USの所見は病理学的特徴を反映するため，正確なUS診断には病理学的特徴に関する知識が不可欠である．US機器の近年の進歩によって，腫瘍悪性度や正確な位置診断など，さらに多くの情報も得られるようになってきた．HCCの悪性度評価は，腫瘍が小さい場合の治療方針決定に重要であり，特にカラードプラや造影USを使用した血流動態の診断が有用である．これに加え近年，低速血流を検知することができるSuperb Microvascular Imaging等の新たな微細血流描出法も開発され，さらなる診断精度の向上に期待がもたれる．一方でFusion imagingは，経皮的なラジオ波焼灼術やマイクロ波凝固療法の補助だけではなく，通常の検査では描出困難な微小HCCの検出補助にも不可欠な技術となっている．本稿では，HCCの診断と治療における実臨床での超音波検査およびSonazoid造影超音波検査の役割について概説する．

Ultrasonography (US) is a major, sustainable hepatocellular carcinoma (HCC) surveillance method as it provides inexpensive, real-time, and noninvasive detection. Since US findings are based on pathological features, knowledge of pathological features is essential for delivering a correct US diagnosis. Recent advances in US equipment have made it possible to provide more information, such as malignancy potential and accurate localization diagnosis of HCC. Evaluation of malignancy potential is important to determine the treatment strategy, especially for small HCC. Diagnosis of blood flow dynamics using color Doppler and contrast-enhanced US is one of the most definitive approaches for evaluating HCC malignancy potential. Recently, a new Doppler microvascular imaging technique, superb microvascular imaging, which can detect Doppler signals generated by low-velocity blood flow, was developed. A fusion imaging system, another innovative US technology, has already become an indispensable technology over the last few years not only for US-guided radiofrequency ablation but also for the detection of small, invisible HCC. This article reviews the evidence on the use of ultrasound and contrast-enhanced ultrasound with Sonazoid for the practical management of HCC.