南 康範^{1, 2}, 工藤 正俊^{1, 2}, 河野 優子^{2, 3}

Yasunori MINAMI^{1, 2}, Masatoshi KUDO^{1, 2}, Yuko KONO^{2, 3}

¹近畿大学消化器内科, ²ACR CEUS LI-RADS Working Group, ³Division of Gastroenterology and Hepatology, University of California

¹Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, ²ACR CEUS LI-RADS Working Group, ³Division of Gastroenterology and Hepatology, University of California

キーワード : contrast-enhanced sonography, hepatocellular carcinoma, LI-RADS, US LI-RADS, CEUS LI-RADS, Sonazoid, Lumason/SonoVue, Definity/Luminity

LI-RADS（Liver Imaging Reporting and Data System）とはAmerican College of Radiology（ACR）から提唱されている肝細胞癌の診断アルゴリズムで，LI-RADSにはUSによるスクリーニングを目的としたUS LI-RADS，造影所見による診断を目的としたCT/MRI LI-RADSとCEUS LI-RADS，そして治療効果判定のCT/MRI LI-RADS treatment response algorithmがある．最近ではLI-RADSを用いたレポーティングシステムが米国の病院に広く採用されるようになり，肝細胞癌診断の標準化につながった．そして，2018年に米国肝臓学会によってLI-RADSが肝細胞癌の診断基準として正式に採用されるに至った．また，CT/MRI LI-RADSは11ヵ国語，CEUS LI-RADS は8ヵ国語の言語に翻訳され，世界中から注目を集める診断アルゴリズムとなっている．一方，日本では本学会が定めた腹部超音波検診判定マニュアルや肝腫瘤の超音波診断基準が日常診療に広く受け入れられている．現行のCEUS LI-RADSは日本で認可されている超音波造影剤（Sonazoid）に対応していないこともあり，日本の日常診療においてUSおよびCEUS LI-RADSが用いられる機会は非常に限定的である．しかし，CEUS LI-RADSがSonazoidに対応することで将来の世界標準となる可能性もあり，その動向が注視される．

The Liver Imaging Reporting and Data System (LI-RADS), endorsed by the American College of Radiology (ACR), includes four algorithms: ultrasound (US) LI-RADS for hepatocellular carcinoma (HCC) screening and surveillance, contrast-enhanced US (CEUS) LI-RADS and computed tomography/magnetic resonance imaging (CT/MRI) LI-RADS for HCC diagnosis, and CT/MRI LI-RADS treatment response algorithm. Recently, LI-RADS has been adopted in clinical practice throughout the United States, and the standardization and consensus regarding the imaging diagnosis of HCC have been improved. LI-RADS achieved consistency with and integration into the American Association for the Study of Liver Diseases HCC clinical practice guidance in 2018. LI-RADS has been gaining international attention, with CT/MRI LI-RADS and CEUS LI-RADS translations now available in 11 and nine languages, respectively. Meanwhile, two US clinical guidelines, supported by the Japan Society of Ultrasonics in Medicine, the manual for abdominal US in cancer screening and health checkups and the ultrasound diagnostic criteria for hepatic tumors, have been adopted in clinical practice in Japan. Sonazoid is available clinically in Japan but not in the United States; therefore, the use of Sonazoid is not supported by CEUS LI-RADS. At present, US LI-RADS and CEUS LI-RADS are not commonly used in Japan. However, CEUS LI-RADS has the potential to become a global standard in the event of the additional inclusion of Sonazoid. We have to keep our eyes on future developments in the area of CEUS LI-RADS.