Hepatic steatosis: Ultrasound assessment using attenuation imaging (ATI) with liver biopsy correlation

Associations Between Multiparametric US-Based Indicators and Pathological Status in Patients with Metabolic Associated Fatty Liver Disease

OBJECTIVE

Noninvasive evaluation of metabolic dysfunction-associated fatty liver disease (MAFLD) using ultrasonography holds significant clinical value. The associations between ultrasound (US)-based parameters and the pathological spectra remain unclear and controversial. This study aims to investigate the associations thoroughly.

METHODS

The participants with MAFLD undergoing liver biopsy and multiparametric ultrasonography were prospectively recruited from December 2020 to September 2022. Three US-based parameters, namely attenuation coefficient (AC), liver stiffness (LS) and dispersion slope (DS) were obtained. The relationship between these parameters and steatosis grades, inflammation grades and fibrosis stages was examined.

RESULTS

In this study with 116 participants, AC values significantly differed across distinct steatosis grades (p < 0.001), while DS and LS values varied among inflammation grades (p < 0.001) and fibrosis stages (p < 0.001). The area under the receiver operating characteristic curves (AUCs) of AC ranged from 0.82 to 0.84 for differentiating steatosis grades, while AUCs of LS ranged from 0.62 to 0.76 for distinguishing inflammation grades and 0.83-0.95 for discerning fibrosis stages. AUCs for DS ranged from 0.79 to 0.81 in discriminating inflammation grades and 0.80-0.88 for differentiating fibrosis stages. Subgroup analysis revealed that LS demonstrated different trends in inflammation grade but consistent trends in fibrosis stage across subgroups, whereas DS showed consistent trends for both inflammation grade and fibrosis stage across all subgroups.

CONCLUSION

AC values indicate the degree of hepatic steatosis but not inflammation or fibrosis. LS values are determined only by fibrosis stage and are not associated with inflammation grades. DS values are associated with both fibrosis and inflammation grades.

Validation of attenuation imaging coefficient, shear wave elastography, and dispersion as emerging tools for non-invasive evaluation of liver tissue in children

Introduction

The number of children with acute and chronic liver disease is rising. Moreover, liver involvement may be limited to subtle changes in organ texture especially in early childhood and some syndromic conditions, such as ciliopathies. Attenuation imaging coefficient (ATI), shear wave elastography (SWE), and dispersion (SWD) are emerging ultrasound technologies providing data about attenuation, elasticity, and viscosity of liver tissue. This additional and qualitative information has been correlated with certain liver pathologies. However, limited data are available for healthy controls and have mainly been raised in adults.

Methods

This prospective monocentric study was conducted at a university hospital with a specialization in pediatric liver disease and transplantation. Between February and July 2021, 129 children aged 0-17.92 years were recruited. Study participants attended outpatient clinics due to minor illnesses excluding liver or cardiac diseases, acute (febrile) infections or other conditions affecting liver tissue and function. ATI, SWE, and SWD measurements were performed on an Aplio i800 (Canon Medical Systems) with an i8CX1 curved transducer by two different investigators with long-standing experience in pediatric ultrasound according to a standardized protocol.

Results

Considering multiple potential covariates, we derived percentile charts for all 3 devices relying on the Lambda-Mu-Sigma (LMS) approach. 112 children were considered for further analysis, excluding those with abnormal liver function and under-/overweight (BMI SDS<-1.96/> 1.96, respectively). Age range was 0-17.92 years (mean 6.89±0.50SD), 58% were male. The mean duration of the ultrasound examination (basic ultrasound plus SWE, SWD, and ATI) was 6.67±0.22 minutes and it was well tolerated in 83% (n=92) of cases. While ATI was related to age, SWD was found to depend on BMI SDS, and SWE on abdominal wall thickness and sex. ATI correlated with neither SWE nor SWD, but SWE was correlated with SWD.

Conclusions

Our study provides norm values and reference charts for ATI, SWE, and SWD considering important covariates including age, sex and, BMI. This may help to implement these promising tools into imaging diagnostics of liver disease and to improve the diagnostic relevance of liver ultrasound. In addition, these noninvasive techniques proved to be time-effective and highly reliable, which make them ideal for application in children.

Correlation between hepatorenal index and attenuation imaging for assessing hepatic steatosis

INTRODUCTION

Hepatic steatosis screening is required to assess high-risk populations, identify those for intervention, monitor response and prevent disease progression and complications. Liver biopsy and magnetic resonance imaging proton density fat fraction are current gold standards, but are limited by biopsy risk factors, patient tolerance and cost. Non-invasive, cost-effective, semi-quantitative and quantitative ultrasound assessment exists. The aim of this study was to assess the correlation between the semi-quantitative hepatorenal index (HRI) to assess hepatic steatosis using the quantitative attenuation imaging (ATI) as a reference standard, in adults with varied suspected liver pathologies.

METHODS

Data were collected prospectively between April 2019 and March 2020 at a tertiary institution on any patient >18 years referred to US assessment of suspected liver pathology. The only exclusion criteria were absent or invalid HRI or ATI measurements. Three hundred fifty eight patients were included.

RESULTS

There was a significant weak positive correlation between HRI and ATI (r = 0.351, P < 0.001) and between HRI steatosis grade (SG) and ATI SG (r = 0.329, P < 0.001), using previously established cut-off values. With ATI as the reference standard, there was no significant correlation between HRI and hepatic steatosis within steatosis grades, nor for no (SG = 0) or any (SG > 0) hepatic steatosis.

CONCLUSIONS

Our study in a typical heterogeneous clinical population suggests the semi-quantitative HRI is of limited use in hepatic steatosis imaging. As HRI is the objective measure of the subjective brightness (B)-mode assessment, this imaging feature may not be as reliable as previously thought. Quantitative ATI may be the preferred non-invasive technique for hepatic steatosis assessment.