神山 直久

Naohisa KAMIYAMA

GEヘルスケア超音波製品開発部

Ultrasound Division, GE Healthcare

キーワード : ultrasound tissue characterization, Q-US, chronic liver disease, attenuation measurement, fatty liver

超音波診断装置の受信信号には生体内の様々な物理情報が含まれており，これを利用して新たな診断情報を提供するための研究が古くからなされている．本稿では，肝臓の組織性状診断に対して筆者がこれまでに行ってきた研究開発内容について，その歴史を振り返りながら概説を行う．肝実質のテクスチャ解析では，当初は肝線維化の特徴量抽出を目的に検討を行ってきたが，肝脂肪化の定量にも好適（むしろ有利）であることの知見が得られ，そのニーズに合わせて解析アルゴリズムと装置機能の仕様が改良されていった．その後，非アルコール性脂肪肝炎（non-alcoholic steatohepatitis：NASH）早期発見の重要性を受け，脂肪肝に伴う超音波減衰の定量化の研究開発に移行し，いくつかの試作を重ねた結果，リアルタイム定量計測機能の製品化が実現した．

The ultrasound echo signals from organs contain various physical information, and many studies have been conducted for a long time to provide new diagnostic information using these signals. In this article, an overview of the research and development that the author has conducted for the diagnosis of liver tissue characteristics are described while looking back on the history. In the case of texture analysis, the purpose of the study was initially to extract the features of liver fibrosis, but it was found that it is suitable (rather advantageous) for the quantification of fatty liver. Thus, the analysis algorithm and product specifications were also improved to meet that need. As for fatty liver, the importance of early detection of non-alcoholic steatohepatitis (NASH) has increased, so we extended the investigation to quantification of the attenuation coefficient of the liver, and after some trials of prototypes, the real-time quantitative measurement function was realized.