Development of a multiparametric ultrasound image using an integrated system and method to assess hepatic steatosis

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease that includes a progression from steatosis, nonalcoholic steatohepatitis (NASH), to cirrhosis. Currently, liver biopsy is the gold standard for identifying the histologic characteristics of NAFLD; nevertheless, its use is restricted due to its invasiveness, sample inaccuracy, and other hazards. There is an ongoing clinical need for the ability to detect, accurately stage, and reliably monitor NAFLD noninvasively. We have recently presented an in vivo multiparametric ultrasound (mpUS) imaging method for the evaluation of NAFLD. The mpUS imaging combines contrast-enhanced ultrasound (CEUS), shear wave elastography (SWE), and H-scan ultrasound (US) measurements. In this study, we developed a mpUS map for the detection of early liver steatosis. Using Sprague-Dawley rats fed either standard control chow $(N=8)$ or a methionine and choline deficient (MCD) diet ($N=12$) that is known to induce liver steatosis, mpUS imaging was performed at baseline and again at 2 wk. After the animals were euthanized, the livers were removed for ex vivo examination. The MCD diet fed animals showed statistically significant differences ($p\lt0.05$) in their mean mpUS map data between baseline and two weeks. These results were confirmed by histological findings showing that rats given the MCD diet had liver steatosis.