Non-invasive assessment of nonalcoholic fatty liver disease: shear wave elastography and ultrasound-guided attenuation parameter

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K09371
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Gastroenterology
• Research Institution: Iwate Medical University
• Principal Investigator: Kuroda Hidekatsu 岩手医科大学, 医学部, 特任准教授 (70382596)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: NASH / 肝線維化 / 肝脂肪化 / 超音波エラストグラフィ / 超音波減衰イメージング

Outline of Final Research Achievements

We analyzed 133 NAFLD patients. 2D-shear wave elastography (SWE), Ultrasound-guided attenuation parameter (UGAP), and liver biopsy were performed at our institution. The Liver stiffness (LS) of each fibrosis stage was F0/F1/F2/F3/F4：5.6/6.3/7.8/9.4/14.9 (kPa), respectively, demonstrating a stepwise increase with increasing severity of liver fibrosis (p<0.0001). Attenuation coefficient (AC) of in each steatosis grade was S0/S1/S2/S3：0.43/0.57/0.68/0.72 (dB/cm/MHz), respectively, demonstrating a stepwise increase with increasing severity of liver steatosis (p<0.0001). By multiple logistic regression analysis, P＝1/(1＋e-λ)，λ=0.478×LS+20.242×AC-14.196 were calculated, which form a calculated composite score for the diagnosis of NASH. The AUROC of this scoring model for predicting NASH was 0.889.　Non-invasive ultrasound evaluation using 2D-SWE and UGAP　may estimate liver fibrosis and steatosis, and which developed a new scoring system for detecting NASH accurately.

Free Research Field

消化器、肝疾患、超音波診断

Academic Significance and Societal Importance of the Research Achievements

超音波を駆使し、エラストグラフィと減衰イメージングの2つのモダリティの長所を活かすことで、NASHの組織性状変化をリアルタイムかつ低侵襲に定量化する試みは、これまでにない新しい技術開発の基盤となり独創性が高い。また、本研究が臨床応用されれば、低侵襲、低コストで繰り返し可能な超音波検査がNASH診断の主軸となり、肝生検をする事なくNASHの早期拾い上げや早期治療導入が可能で、スクリーニングへの応用、超音波診断技術の標準化など臨床的価値が非常に高い。さらには、超音波画像のテクスチャ解析は、コンピュータ支援画像診断技術の最先端を担う手法であり、独創性や創造性の高い研究と考える。