Assessment of Hepatic Steatosis in Nonalcoholic Fatty Liver Disease by Using Quantitative US

Abstract

N onalcoholic fatty liver disease (NAFLD) affects approximately 25% of the human population (1,2) and may soon overtake hepatitis C as the leading cause of liver transplantation (3). The earliest and characteristic histologic feature of NAFLD is hepatic steatosis, defined as the accumulation of fat droplets within hepatocytes. Steatosis can lead to nonalcoholic steatohepatitis, a more rapidly progressive variant of NAFLD. Nonalcoholic steatohepatitis occurs in 20% of adults with NAFLD, and can contribute to development of fibrosis, cirrhosis, and even hepatocellular carcinoma (1,2). Liver biopsy is the current reference standard for NAFLD diagnosis (4). Proton density fat fraction (PDFF) measured at confounder-corrected chemical shift-encoded MRI is an accurate, repeatable, and reproducible noninvasive method for hepatic steatosis quantification (5-7). However, chemical shift-encoded MRI is not routinely available.There is a critical need to develop noninvasive, widely available, accurate, and cost-effective methods to assess steatosis. US is a promising modality for this purpose, but conventional US is limited by its qualitative nature, system and operator dependency, and modest accuracy (4). Various methods have been investigated to extract quantitative information from US to improve steatosis assessment (8-16), each with its own strengths and weaknesses. For example, the hepatorenal index is accurate for steatosis assessment ( 8), but it depends on the right kidney being normal and disease-free. The right kidney is not always visible on US images. Controlled attenuation parameter is

Novel Method for Ultrasound‐Derived Fat Fraction Using an Integrated Phantom

“…In a recent clinical study, Han et al 43 used a linear model of the Lizzi-Feleppa midband and k parameter to predict the fat fraction. They reported a Pearson Figure 3 Bland-Altman plot of the difference between UDFF and MRI-PDFF versus the average of the measures.…”

“…The horizontal lines indicate the mean and ± 1.96 SD values. This study included some of the participants of the study by Han et al 43 However, the data analysis was different in several aspects. First, a linear model was used in the work of Han et al 43 to predict the fat fraction, whereas the UDFF model is a quadratic fit using AC and BSC parameters.…”

“…This study included some of the participants of the study by Han et al 43 However, the data analysis was different in several aspects. First, a linear model was used in the work of Han et al 43 to predict the fat fraction, whereas the UDFF model is a quadratic fit using AC and BSC parameters. Moreover, the RP data used in the analysis by Han et al 43 were acquired immediately after participants' US scans.…”

“…First, a linear model was used in the work of Han et al 43 to predict the fat fraction, whereas the UDFF model is a quadratic fit using AC and BSC parameters. Moreover, the RP data used in the analysis by Han et al 43 were acquired immediately after participants' US scans. The UDFF model used multiple speckle realizations of an RP acquired offline.…”

“…In a recent clinical study of 102 participants, Han et al 43 developed multivariate QUS models to detect hepatic steatosis and predict the fat fraction. The results showed good agreement between the predicted fat fraction and MRI-PDFF.…”