Noninvasive assessment of liver steatosis using ultrasound methods

Abstract

Hepatic steatosis is a condition frequently encountered in clinical practice, with potential progression towards chirrhosis and hepatocellular carcinoma. Ultrasonography (US) is one of the noninvasive imaging techniques used in the diagnosis of steatosis. We will review the US diagnostic criteria, the US performance in the diagnosis and grading of hepatic steatosis, the US steatosis models, but also its limitations in the diagnosis of steatosis. In addition, we will discuss 2 modern methods of assessing hepatic steatosis using ultrasounds, namely the computerized processing of data forming the US image and the controlled attenuation parameter measured with unidimensional transient elastography.

Diagnostic Accuracy of Controlled Attenuation Parameter Measured by Transient Elastography for the Non-invasive Assessment of Liver Steatosis: a Prospective Study

“…The majority of patients were female (61.2%), with a median age of 51 years. The median size of the liver biopsy specimens was 15 (12)(13)(14)(15)(16)(17)(18)(19)(20) mm, with a median of 14 (10-22) portal spaces. The clinical, biochemical and histopathological characteristics of the patients are presented in Table I.…”

“…Ultrasonography is considered the imaging technique of choice for steatosis screening given its low cost, safety and wide availability [16], but it is operator-dependent [14] and it detects steatosis only if it involves at least 20% of all hepatocytes [17]. The method cannot establish with certainty the degree of fatty infiltration and cannot accurately discriminate steatosis from fibrosis, since both result in increased liver echogenity [18]. The ultrasonographic hepatorenal index was used in an attempt to grade steatosis [19], but it is cumbersome and time-consuming and requires specialized software.…”

Performance of Ultrasound Techniques and the Potential of Artificial Intelligence in the Evaluation of Hepatocellular Carcinoma and Non-Alcoholic Fatty Liver Disease

“…Another noteworthy remark was the fact that the sensitivity and specificity of hepatic vein blurring was higher than the one of the portal vein blurring, and there was a high concordance between hepatic vein blurring and the increased echogenicity. Therefore, the combination of portal vein blurring and liver brightness was a better sonographic predictor for hepatic steatosis [30].…”

“…The use of computers in US image analysis started several years ago with the introduction of methods like grayscale analysis, ultrasound histogram, attenuation and/or texture information, and computer-assisted quantitative analysis of ultrasound beam echo amplitude [120][121][122]. Another method that can appraise steatosis severity is the computerized calculation of the hepatorenal ratio, with a sensibility of 91.3% and a specificity of 83% if the hepato-renal difference is ≥7 dB [30]. However, the efficacy of these rudimentary computerized methods remains questionable and the progress towards the applications of artificial intelligence is within our grasp.…”

Non-Alcoholic Fatty Liver Disease in Obese Youth With Insulin Resistance and Type 2 Diabetes

“…However, US does not support the diagnosis or grading of hepatic steatosis in children and, although a paper published in 1997 gave a greater diagnostic power to the US (208), recent evidence suggests a comparable diagnostic accuracy between ALT and US, with a moderate capacity to detect pathological fat accumulation (209). Therefore, it is currently used as screening test (210) The inability to distinguish between a simple steatosis from steatohepatitis and to quantify fatty infiltration are the main limits correlated to this imaging method (211).…”