Hepatorenal Index by B-Mode Ratio Versus Imaging and Fatty Liver Index to Diagnose Steatosis in Alcohol-Related and Nonalcoholic Fatty Liver Disease

Modern ultrasound techniques for diagnosing liver steatosis and fibrosis: A systematic review with a focus on biopsy comparison

BACKGROUND

This review evaluated the diagnostic effectiveness of various ultrasound (US) methods compared to liver biopsy.

AIM

To determine the diagnostic accuracy of US techniques in assessing liver fibrosis and steatosis in adults, using the area under the receiver operating characteristic curve (AUROC) as the standard measure.

METHODS

The review included original retrospective or prospective studies published in the last three years in peer-reviewed medical journals, that reported AUROC values. Studies were identified through PubMed searches on January 3 and April 30, 2024. Quality was assessed using the QUADAS-2 tool. Results were tabulated according to the diagnostic method and the type of liver pathology.

RESULTS

The review included 52 studies. For liver fibrosis detection, 2D-shear wave elastography (SWE) AUROCs ranged from 0.54 to 0.994, showing better accuracy for advanced stages. Modifications, including 2D-SWE with propagation map guidance and supersonic imagine achieved AUROCs of 0.84 to nearly 1.0. point SWE and classical SWE had AUROCs of 0.741-0.99, and 0.507-0.995, respectively. Transient elastography (TE), visual TE, vibration-controlled TE (VCTE), and FibroTouch reported AUROCs close to 1.0. For steatosis, VCTE with controlled attenuation parameter showed AUROCs up to 0.89 (for ≥ S1), acoustic radiation force impulse ranged from 0.762 to 0.784, US attenuation parameter from 0.88 to 0.93, and normalized local variance measurement from 0.583 to 0.875. Most studies had a low risk of bias across all or most domains, but evidence was limited by variability in study quality and small sample sizes. Innovative SWE variants were evaluated in a single study.

CONCLUSION

Modern US techniques can serve as effective noninvasive diagnostic tools for liver fibrosis and steatosis, with the potential to reduce the reliance on biopsies.

The Effect of Backscatter Anisotropy in Assessing Hepatic Steatosis Using Ultrasound Hepatorenal Index

OBJECTIVES

To discuss challenges in assessing hepatic steatosis using ultrasound hepatorenal index (HRI).

METHODS

We retrospectively analyzed HRI and liver magnetic resonance imaging-based proton density fat fraction (MRI-PDFF) in 134 adult participants (53 men and 81 women, mean age 55 years). The diagnostic performance of HRI for determining hepatic steatosis was tested by the area under the receiver operating characteristic curve (AUROC) using liver MRI-PDFF as the reference. Regression plots were employed to compare the sampling sites in liver and kidney that were used to calculate HRIs.

RESULTS

In 11 of 134 cases (8.2%), we failed to acquire HRI measurements. In the remaining 123 cases, AUROC for HRI (cutoff: 1.69 ± 0.13 [mean ± standard deviation]) for defining the HRI threshold for diagnosing hepatic steatosis was 0.83. In 60 of 123 cases (49%) with HRI measurement IQR/median >0.3, slopes of the regression lines in the liver showed backscatter intensity changes consistent with signal attenuation. However, in the kidney, the backscatter intensity was inverted yielding position-dependent HRI cutoff values, mid-pole = 2.24 ± 0.20 and upper pole = 1.08 ± 0.16.

CONCLUSIONS

HRI is used to estimate liver steatosis based on backscattered ultrasound. In order to compensate for effects such as body habitus and transducer frequency, the liver backscatter is divided by backscatter from a corresponding region at the same depth in the right renal cortex. Theoretically, this compensation should make HRI sampling position independent. Yet, due to renal cortical backscatter anisotropy, this compensation method does not work in general, potentially producing inaccurate liver fat estimates.

Consistency analysis of two US techniques for evaluating hepatic steatosis in patients with metabolic dysfunction-associated steatotic liver disease

BACKGROUND

US tools to quantify hepatic steatosis have recently been made clinically available by different manufacturers, but comparative data on their consistency are lacking.

OBJECTIVE

US tools to quantify hepatic steatosis have recently been made clinically available by different manufacturers, but comparative data on their consistency are lacking. The aim of our study was to compare the diagnostic consistency for evaluating hepatic steatosis by two different US techniques, hepatorenal index by B-mode Ratio and attenuation coefficient by attenuation imaging (ATI).

METHODS

Patients with suspicion or previously diagnosed of metabolic dysfunction-associated steatotic liver disease (MASLD) who attended fatty liver consulting room from June 2023 to September 2023 were prospectively recruited. Patients underwent two different US techniques of B-mode Ratio and ATI, and laboratory test were collected. According to previously proposed cut-off values, B-mode Ratio ≥ 1.22, 1.42, 1.54, and ATI ≥ 0.62, 0.70, and 0.78 dB/cm/MH were used for assessing of mild, moderate, and severe hepatic steatosis, respectively. Kappa consistency test was used to evaluate the consistency of hepatic steatosis.

RESULTS

A total of 62 patients were enrolled, including 44 males (71.0%) with an age of (41 ± 13) years and a body mass index of (27.0 ± 3.5) kg/m2. In the hyperlipidemia group, the B-mode Ratio and ATI were significantly higher than those in the non-hyperlipidemia group, with values of 1.68 ± 0.39 vs. 1.28 ± 0.35 (p = 0.001) and 0.74 ± 0.12 dB/cm/MH vs. 0.64 ± 0.11 dB/cm/MH (p = 0.005), respectively. The correlation coefficient between B-mode Ratio and ATI was 0.732 (p < 0.001). Using B-mode Ratio and ATI as diagnostic criteria for MASLD, the proportion of patients with MASLD was 79% and 82%, respectively. The Kappa coefficient for assessing MASLD was 0.90 (p < 0.001). Furthermore, these two different US techniques were used for grading hepatic steatosis, with no, mild, moderate, and severe steatosis accounting for 21%, 18%, 13%, and 48%, as well as 18%, 29%, 22%, and 31%, respectively. The linear weighted Kappa coefficient for staging hepatic steatosis was 0.78 (95% confidence interval: 0.68-0.87, p < 0.001).

CONCLUSION

The non-invasive methods of two different US techniques based on B-mode Ratio and ATI have good consistency for evaluating hepatic steatosis, and can be used for large-scale community screening.

Enhanced Diagnostic Imaging: Arrival-Time Parametric Imaging in Contrast-Enhanced Ultrasound for Multi-Organ Assessment

Contrast-enhanced ultrasonography (CEUS) is a novel technology in ultrasound medicine that has gained widespread application in clinical practice. While CEUS offers various quantitative and qualitative parameters, it is limited by factors such as the single-color transient coverage of the contrast agent and its dependence on the operator, rendering it less suitable for detecting blood in organ lesions. Additionally, fluid dynamic perfusion remains unsatisfactory. Recently, arrival-time parametric imaging (At-PI) has emerged as a promising alternative; this technology not only uses color overlay to statically represent the dynamic perfusion of blood flow within lesions but also enhances visualization, minimizes operator variability, and provides insights into the vascular patterns of both benign and malignant lesions. At-PI has demonstrated numerous advantages and has been successfully applied to the liver, adrenal gland, breast, lymph nodes, prostate, and gastrointestinal tract, yielding encouraging preliminary results. This review synthesizes existing research findings, highlights significant parameters, examines the current global research landscape regarding this technology, and outlines the research directions pursued by scholars in the field. Furthermore, we offer a critical analysis and discussion of the limitations of these findings. The ultimate aim is to elucidate the role of At-PI in clinical diagnosis and treatment.

Revisiting the Hepatorenal Index in the Quantification of Hepatic Steatosis: How it is done and the utility

METHODS

Twenty-three peer-reviewed articles on HRI measurements published between 2018 through 2023 were reviewed, and 11 were selected based on common subjects. The search terms included "hepatorenal index," "HRI," "HRI ultrasound," "hepatorenal ultrasound index," and "HRI ultrasound measurement."Three common subject areas were identified in the literature and synthesized down to 11 articles. The common subjects identified were HRI technique, HRI limitations, and HRI diagnostic accuracy. The matrix provided a quick overview of the general information in each piece, aiding in the paper's overall organization. Thirteen articles were rejected as not relevant or out of date. The research question leading this review was, "What does the literature say about the value of HRI in determining moderate to severe hepatic steatosis?"

RESULTS

The literature revealed that HRI could be valuable in determining moderate to severe hepatic steatosis. HRI could not accurately determine normal or mild steatosis and has several limitations.

CONCLUSIONS

HRI is a more objective method for determining the degree of hepatic steatosis compared with traditional B-mode ultrasound scoring and does not require additional or specialized equipment. Many studies excluded patients with various liver diseases, which may not make HRI a practical tool for clinical usefulness. Further studies should be conducted with larger patient cohorts, a greater degree of hepatic steatosis, and determine specific standardized cutoff values.

Validity of fatty liver prediction scores for diagnosis of fatty liver by Fibroscan

BACKGROUND

The Korea National Health and Nutrition Examination Survey nonalcoholic fatty liver disease (K-NAFLD) score was recently developed with the intent to operationally define nonalcoholic fatty liver disease (NAFLD). However, there remained an external validation that confirmed its diagnostic performance, especially in patients with alcohol consumption or hepatitis virus infection.

METHODS

Diagnostic accuracy of the K-NAFLD score was evaluated in a hospital-based cohort consisting of 1388 participants who received Fibroscan®. Multivariate-adjusted logistic regression models and the contrast estimation of receiver operating characteristic curves were used for validation of the K-NAFLD score, fatty liver index (FLI), and hepatic steatosis index (HSI).

RESULTS

K-NAFLD-moderate [adjusted odds ratio (aOR) = 2.53, 95% confidence interval (CI): 1.13-5.65] and K-NAFLD-high (aOR = 4.14, 95% CI: 1.69-10.13) groups showed higher risks of fatty liver compared to the K-NAFLD-low group after adjustments for demographic and clinical characteristics, and FLI-moderate and FLI-high groups revealed aORs of 2.05 (95% CI: 1.22-3.43) and 1.51 (95% CI: 0.78-2.90), respectively. In addition, the HSI was less predictive for Fibroscan®-defined fatty liver. Both K-NAFLD and FLI also demonstrated high accuracy in the prediction of fatty liver in patients with alcohol consumption and chronic hepatitis virus infection, and the adjusted area under curve values were comparable between K-NAFLD and FLI.

CONCLUSIONS

Externally validation of the K-NAFLD and FLI showed that these scores may be a useful, noninvasive, and non-imaging modality for the identification of fatty liver. In addition, these scores also predicted fatty liver in patients with alcohol consumption and chronic hepatitis virus infection.

Prospective study comparing hepatic steatosis assessment by magnetic resonance imaging and four ultrasound methods in 105 successive patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is becoming a major health problem, resulting in hepatic, metabolic and cardio-vascular morbidity.

AIM

To evaluate new ultrasonographic tools to detect and measure hepatic steatosis.

METHODS

We prospectively included 105 patients referred to our liver unit for NAFLD suspicion or follow-up. They underwent ultrasonographic measurement of liver sound speed estimation (SSE) and attenuation coefficient (AC) using Aixplorer MACH 30 (Supersonic Imagine, France), continuous controlled attenuation parameter (cCAP) using Fibroscan (Echosens, France) and standard liver ultrasound with hepato-renal index (HRI) calculation. Hepatic steatosis was then classified according to magnetic resonance imaging proton density fat fraction (PDFF). Receiver operating curve (ROC) analysis was performed to evaluate the diagnostic performance in the diagnosis of steatosis.

RESULTS

Most patients were overweight or obese (90%) and had metabolic syndrome (70%). One third suffered from diabetes. Steatosis was identified in 85 patients (81%) according to PDFF. Twenty-one patients (20%) had advanced liver disease. SSE, AC, cCAP and HRI correlated with PDFF, with respective Spearman correlation coefficient of -0.39, 0.42, 0.54 and 0.59 (P < 0.01). Area under the receiver operating characteristic curve (AUROC) for detection of steatosis with HRI was 0.91 (0.83-0.99), with the best cut-off value being 1.3 (Se = 83%, Sp = 98%). The optimal cCAP threshold of 275 dB/m, corresponding to the recent EASL-suggested threshold, had a sensitivity of 72% and a specificity of 80%. Corresponding AUROC was 0.79 (0.66-0.92). The diagnostic accuracy of cCAP was more reliable when standard deviation was < 15 dB/m with an AUC of 0.91 (0.83-0.98). An AC threshold of 0.42 dB/cm/MHz had an AUROC was 0.82 (0.70-0.93). SSE performed moderately with an AUROC of 0.73 (0.62-0.84).

CONCLUSION

Among all ultrasonographic tools evaluated in this study, including new-generation tools such as cCAP and SSE, HRI had the best performance. It is also the simplest and most available method as most ultrasound scans are equipped with this module.

Non-invasive evaluation of liver steatosis with imaging modalities: New techniques and applications

In the world, nonalcoholic fatty liver disease (NAFLD) accounts for majority of diffuse hepatic diseases. Notably, substantial liver fat accumulation can trigger and accelerate hepatic fibrosis, thus contributing to disease progression. Moreover, the presence of NAFLD not only puts adverse influences for liver but is also associated with an increased risk of type 2 diabetes and cardiovascular diseases. Therefore, early detection and quantified measurement of hepatic fat content are of great importance. Liver biopsy is currently the most accurate method for the evaluation of hepatic steatosis. However, liver biopsy has several limitations, namely, its invasiveness, sampling error, high cost and moderate intraobserver and interobserver reproducibility. Recently, various quantitative imaging techniques have been developed for the diagnosis and quantified measurement of hepatic fat content, including ultrasound- or magnetic resonance-based methods. These quantitative imaging techniques can provide objective continuous metrics associated with liver fat content and be recorded for comparison when patients receive check-ups to evaluate changes in liver fat content, which is useful for longitudinal follow-up. In this review, we introduce several imaging techniques and describe their diagnostic performance for the diagnosis and quantified measurement of hepatic fat content.

US Backscatter for Liver Fat Quantification: An AIUM-RSNA QIBA Pulse-Echo Quantitative Ultrasound Initiative

Nonalcoholic fatty liver disease (NAFLD) is believed to affect one-third of American adults. Noninvasive methods that enable detection and monitoring of NAFLD have the potential for great public health benefits. Because of its low cost, portability, and noninvasiveness, US is an attractive alternative to both biopsy and MRI in the assessment of liver steatosis. NAFLD is qualitatively associated with enhanced B-mode US echogenicity, but visual measures of B-mode echogenicity are negatively affected by interobserver variability. Alternatively, quantitative backscatter parameters, including the hepatorenal index and backscatter coefficient, are being investigated with the goal of improving US-based characterization of NAFLD. The American Institute of Ultrasound in Medicine and Radiological Society of North America Quantitative Imaging Biomarkers Alliance are working to standardize US acquisition protocols and data analysis methods to improve the diagnostic performance of the backscatter coefficient in liver fat assessment. This review article explains the science and clinical evidence underlying backscatter for liver fat assessment. Recommendations for data collection are discussed, with the aim of minimizing potential confounding effects associated with technical and biologic variables.