Multiparametric liver assessment in patients successfully treated for hepatitis C: a 4-year follow-up.

BACKGROUND: Hepatitis C virus (HCV) is a major cause of chronic liver disease, in which liver stiffness increases. Liver stiffness measurements (LSM) are therefore essential in diagnosing liver diseases and predicting disease development. The study objective was to perform a comprehensive prospective assessment of the liver before, after and 4 years after treatment for HCV, including an assessment of the long-term outcome of fibrosis, steatosis and inflammation. METHODS AND FINDINGS: Patients eligible for HCV treatment were included prospectively in 2018 (n = 47). Liver stiffness was measured using transient elastography and 2D shear-wave elastography (SWE). Blood tests, B-mode ultrasound (US) and SWE, were performed before, after (end of treatment [EOT]), 3 months after (EOT3) and 4 years after treatment (4Y). At the final visit, we added attenuation imaging and shear-wave dispersion slope (SWDS) measurements to assess steatosis and inflammation. Three months after treatment, the sustained virologic response rate was 93%. The median liver stiffness for baseline, EOT, EOT3 and 4Y was 8.1, 5.9, 5.6 and 6.3 kPa, respectively. There was a significant reduction in liver stiffness from baseline to EOT, and from EOT to EOT3. After 4 years, the mean attenuation coefficient (AC) was 0.58 dB/cm/MHz, and the mean SWDS value was 14.3 (m/s)/kHz. CONCLUSION: The treatment for HCV was highly effective. Measurements of liver stiffness decreased significantly after treatment and remained low after 4 years. AC measurements indicated low levels of liver steatosis. Shear-wave dispersion values indicated inflammation of the liver, but the clinical implication is undetermined and should be explored in larger studies.Clinicaltrials.gov: NCT03434470. ABBREVIATIONS: AC: attenuation coefficient; APRI: aspartate aminotransferase to platelet ratio index; ATI: attenuation imaging; cACLD: compensated advanced chronic liver disease; CAP: controlled attenuation parameter; FIB-4: Fibrosis-4 Index for liver fibrosis; HCC: hepatocellular carcinoma; LSM: liver stiffness measurement; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; SWDS: shear-wave dispersion slope; SWE: shear-wave elastography; US: ultrasound.

Spectral-based Quantitative Ultrasound Imaging Processing Techniques: Comparisons of RF Versus IQ Approaches.

Quantitative ultrasound (QUS) is an imaging technique which includes spectral-based parameterization. Typical spectral-based parameters include the backscatter coefficient (BSC) and attenuation coefficient slope (ACS). Traditionally, spectral-based QUS relies on the radio frequency (RF) signal to calculate the spectral-based parameters. Many clinical and research scanners only provide the in-phase and quadrature (IQ) signal. To acquire the RF data, the common approach is to convert IQ signal back into RF signal via mixing with a carrier frequency. In this study, we hypothesize that the performance, that is, accuracy and precision, of spectral-based parameters calculated directly from IQ data is as good as or better than using converted RF data. To test this hypothesis, estimation of the BSC and ACS using RF and IQ data from software, physical phantoms and in vivo rabbit data were analyzed and compared. The results indicated that there were only small differences in estimates of the BSC between when using the original RF, the IQ derived from the original RF and the RF reconverted from the IQ, that is, root mean square errors (RMSEs) were less than 0.04. Furthermore, the structural similarity index measure (SSIM) was calculated for ACS maps with a value greater than 0.96 for maps created using the original RF, IQ data and reconverted RF. On the other hand, the processing time using the IQ data compared to RF data were substantially less, that is, reduced by more than a factor of two. Therefore, this study confirms two things: (1) there is no need to convert IQ data back to RF data for conducting spectral-based QUS analysis, because the conversion from IQ back into RF data can introduce artifacts. (2) For the implementation of real-time QUS, there is an advantage to convert the original RF data into IQ data to conduct spectral-based QUS analysis because IQ data-based QUS can improve processing speed.

Coincidental items in the definition of metabolic dysfunction-associated fatty liver are useful in identifying patients having significant fibrosis with fatty liver.

AIM: We aimed to establish a method that will identify patients at a high risk for progressive phenotype of fatty liver. METHODS: Patients with fatty liver who underwent liver biopsy between July 2008 and November 2019 were included as cohort 1, and those who underwent abdominal ultrasound screening examination by general physicians between August 2020 and May 2022 served as cohort 2. According to the definition of metabolic dysfunction-associated fatty liver (MAFLD), the subjects were classified by body mass index of ≥23, diabetes mellitus, and coexistence of two or more metabolic risk items. The progressive phenotype of MAFLD is defined by significant fibrosis complicated with either nonalcoholic fatty liver disease activity score ≥4 (BpMAFLD) or steatosis grade ≥2 by ultrasound examination (UpMAFLD). RESULTS: One hundred sixty-eight patients and 233 patients were enrolled in cohorts 1 and 2, respectively. In cohort 1, the prevalence of BpMAFLD was 0% in patients without a complicating factor (n = 10), 13% in those with one complicating factor (n = 67), 32% in those with two (n = 73), and 44% in those with all three complicating factors (n = 36). A logistic regression analysis revealed that factors in the MAFLD definition were significantly associated with BpMAFLD. In cohort 2, a criterion of two or more positive MAFLD definitions was found to have a 97.4% negative predictive value for the diagnosis of UpMAFLD. CONCLUSION: Patients with two or more complicating factors in the MAFLD definition should have further evaluation for liver fibrosis.

A Comparative Study of Ultrasound Attenuation Imaging, Controlled Attenuation Parameters, and Magnetic Resonance Spectroscopy for the Detection of Hepatic Steatosis.

OBJECTIVES: To investigate the methodology and clinical application of ultrasound attenuation imaging (ATI) and comparative analyze the diagnostic performance of ATI and controlled attenuation parameters (CAP) for detecting and grading hepatic steatosis. METHODS: A total of 159 patients with NAFLD were prospectively enrolled. CAP and ATI examinations were performed within a week before proton magnetic resonance spectroscopy (1 H-MRS). Ten liver attenuation coefficient (AC) measurements by ATI were obtained in each patient. The interclass correlation coefficients (ICCs) of the intraobserver consistencies and the ICCs between the median of the first two through the first nine measurements and all 10 measurements were calculated. The correlations between 1 H-MRS, CAP, biological data, and ATI were evaluated. The significant factors associated with ATI and the diagnostic performance of ATI and CAP for detecting hepatic steatosis was evaluated. RESULTS: The median value of AC for detecting hepatic steatosis was 0.831 dB/cm/MHz. For the intraobserver consistency of ATI, the ICC was 0.931. Compared with 10 measurements, a minimum of four ATI measurements was required. The correlation of AC with hepatic fat fraction (HFF) was significantly higher than that of CAP (0.603 vs 0.326, P = .0015). The HFF and triglyceride (TG) were the significant factors for the ATI. The area under the receiver operating characteristics (ROC) curves of ATI and CAP were 0.939 and 0.788 for detecting ≥10% hepatic steatosis; 0.751 and 0.572 for detecting >33% hepatic steatosis. The cutoff values of ATI and CAP were 0.697 dB/cm/MHz and 310 dB/m for detecting ≥10% hepatic steatosis; 0.793 dB/cm/MHz and 328 dB/m for detecting >33% hepatic steatosis. The sensitivity of ATI and CAP were 85.92% and 52.11% for detecting ≥10% hepatic steatosis; 87.50% and 82.14% for detecting >33% hepatic steatosis. The specificity of ATI and CAP were 94.12% and 100% for detecting ≥10% hepatic steatosis; 54.37% and 43.69% for detecting >33% hepatic steatosis. CONCLUSIONS: ATI technology showed excellent intraobserver consistency and the optimal minimum number of ATI measurements was 4. ATI is a promising noninvasive, quantitative and convenient tool for assessing hepatic steatosis.

Interobserver Variability in Ultrasound-Based Liver Fat Quantification.

OBJECTIVES: To assess interobserver variability in ultrasound-based quantitative liver fat content measurements and to determine how much time these quantitative ultrasound (QUS) techniques require. METHODS: One hundred patients with known or suspected of having nonalcoholic fatty liver disease were included in this prospective study. Two observers who were blinded to each other measurements performed tissue attenuation imaging (TAI) and tissue scatter distribution imaging (TSI) techniques independently. Both observers assessed hepatic steatosis visually and obtained 5 measurements for each QUS technique and the median values of the measurements were recorded. Spearman's correlation test was used to assess the correlation between QUS measurements and visual hepatic stetaosis grades. Intraclass correlation coefficient (ICC) test was used to assess interobserver variability in QUS measurements. RESULTS: The median values of TAI measurements for the observers 1 and 2 were 0.75 and 0.74 dB/cm/MHz, respectively. The median values of TSI measurements for the observers 1 and 2 were 93.53 and 92.58, respectively. The interobserver agreement in TAI (ICC: 0.970) and TSI (ICC: 0.938) measurements were excellent. The mean of the required time period for TAI technique were 55.1 ± 7.8 and 59.9 ± 6.6 seconds for the observers 1 and 2, respectively. The mean of the required time period for TSI technique were 49.1 ± 5.8 and 54.1 ± 5.4 seconds for the observers 1 and 2, respectively. CONCLUSION: The current study revealed that both TAI and TSI techniques are highly reproducible and can be implemented into daily practice with little additional time requirement.

Quantitative evaluation of hepatic steatosis using attenuation imaging in a pediatric population: a prospective study.

BACKGROUND: Obesity and fatty-liver disease are increasingly common in children. Hepatic steatosis is becoming the most common cause of chronic liver disease during childhood. There is a need for noninvasive imaging methods that are easily accessible, safe and do not require sedation in the diagnosis and follow-up of the disease. OBJECTIVE: In this study, the diagnostic role of ultrasound attenuation imaging (ATI) in the detection and staging of fatty liver in the pediatric age group was investigated using the magnetic resonance imaging (MRI)-proton density fat fraction as the reference. MATERIALS AND METHODS: A total of 140 children with both ATI and MRI constituted the study group. Fatty liver was classified as mild (S1, defined as ≥ 5% steatosis), moderate (S2, defined as ≥ 10% steatosis), or severe (S3, defined as ≥ 20% steatosis) according to MRI-proton density fat fraction values. MRI studies were performed on the same 1.5-tesla (T) MR device without sedation and contrast agent. Ultrasound examinations were performed independently by two radiology residents blinded to the MRI data. RESULTS: While no steatosis was detected in half of the cases, S1 steatosis was found in 31 patients (22.1%), S2 in 29 patients (20.7%) and S3 in 10 patients (7.1%). A strong correlation was found between attenuation coefficient and MRI-proton density fat fraction values (r = 0.88, 95% CI 0.84-0.92; P < 0.001). The area under the receiver operating characteristic curve values of ATI were calculated as 0.944 for S > 0, 0.976 for S > 1 and 0.970 for S > 2, based on 0.65, 0.74 and 0.91 dB/cm/MHz cut-off values, respectively. The intraclass correlation coefficient values for the inter-observer agreement and test-retest reproducibility were calculated as 0.90 and 0.91, respectively. CONCLUSION: Ultrasound attenuation imaging is a promising noninvasive method for the quantitative evaluation of fatty liver disease.

Ultrasound attenuation imaging: a reproducible alternative for the noninvasive quantitative assessment of hepatic steatosis in children.

BACKGROUND: Pediatric hepatic steatosis is a global public health concern, as an increasing number of children are affected by this condition. Liver biopsy is the gold standard diagnostic method; however, this procedure is invasive. Magnetic resonance imaging (MRI)-derived proton density fat fraction has been accepted as an alternative to biopsy. However, this method is limited by cost and availability. Ultrasound (US) attenuation imaging is an upcoming tool for noninvasive quantitative assessment of hepatic steatosis in children. A limited number of publications have focused on US attenuation imaging and the stages of hepatic steatosis in children. OBJECTIVE: To analyze the usefulness of ultrasound attenuation imaging for the diagnosis and quantification of hepatic steatosis in children. MATERIAL AND METHODS: Between July and November 2021, 174 patients were included and divided into two groups: group 1, patients with risk factors for steatosis (n = 147), and group 2, patients without risk factors for steatosis (n = 27). In all cases, age, sex, weight, body mass index (BMI), and BMI percentile were determined. B-mode US (two observers) and US attenuation imaging with attenuation coefficient acquisition (two independent sessions, two different observers) were performed in both groups. Steatosis was classified into four grades (0: absent, 1: mild, 2: moderate and 3: severe) using B-mode US. Attenuation coefficient acquisition was correlated with steatosis score according to Spearman's correlation. Attenuation coefficient acquisition measurements' interobserver agreement was assessed using intraclass correlation coefficients (ICC). RESULTS: All attenuation coefficient acquisition measurements were satisfactory without technical failures. The median values for group 1 for the first session were 0.64 (0.57-0.69) dB/cm/MHz and 0.64 (0.60-0.70) dB/cm/MHz for the second session. The median values for group 2 for the first session were 0.54 (0.51-0.56) dB/cm/MHz and 0.54 (0.51-0.56) dB/cm/MHz for the second. The average attenuation coefficient acquisition was 0.65 (0.59-0.69) dB/cm/MHz for group 1 and 0.54 (0.52-0.56) dB/cm/MHz for group 2. There was excellent interobserver agreement at 0.94 (95% CI 0.92-0.96). There was substantial agreement between both observers (κ = 0.77, with a P < 0.001). There was a positive correlation between ultrasound attenuation imaging and B-mode scores for both observers (r = 0.87, P < 0.001 for observer 1; r = 0.86, P < 0.001 for observer 2). Attenuation coefficient acquisition median values were significantly different for each steatosis grade (P < 0.001). In the assessment of steatosis by B-mode US, the agreement between the two observers was moderate (κ = 0.49 and κ = 0.55, respectively, with a P < 0.001 in both cases). CONCLUSION: US attenuation imaging is a promising tool for the diagnosis and follow-up of pediatric steatosis, which provides a more repeatable form of classification, especially at low levels of steatosis detectable in B-mode US.

Hepatic Fat Quantification With Novel Ultrasound Based Techniques: A Diagnostic Performance Study Using Magnetic Resonance Imaging Proton Density Fat Fraction as Reference Standard.

Purpose: To assess the diagnostic performances of novel Tissue attenuation imaging (TAI) and Tissue scatter distribution imaging (TSI) tools in quantification of liver fat content using magnetic resonance imaging proton density fat fraction (MRI PDFF) as reference standard. Methods: Eighty consecutive patients with known or suspected non-alcoholic fatty liver disease (NAFLD) who volunteered to participate in the study comprised the study cohort. All patients underwent MRI PDFF scan and quantitative ultrasound (QUS) imaging using TAI and TSI tools. The cutoff values of ≥5%, ≥16.3% and ≥21.7% on MRI PDFF were used for mild, moderate and severe steatosis, respectively. Area under the Receiver operating characteristic (AUROC) curves were used to assess the diagnostic performance of TAI and TSI in detecting different grades of hepatic steatosis. Results: The AUROCs of TAI and TSI tools in detecting hepatosteatosis (MRI PDFF ≥5%), were 0.95 [95% Confidence Interval (CI): 0.91-0.99] (P < 0.001) and 0.96 (95% CI: 0.93-0.99) (P < 0.001), respectively. In distinguishing between different grades of steatosis, the values of 0.75, 0.86 and 0.96 dB/cm/MHz have 88%, 88% and 100% sensitivity, respectively, for TAI tool; and the values of 92.44, 96.64 and 99.45 have 90%, 92% and 91.7% sensitivity, respectively, for TSI tool. Conclusion: TAI and TSI tools accurately quantify liver fat content and can be used for the assessment and grading of hepatosteatosis in patients with known or suspected NAFLD.

Diagnosis of hepatic steatosis based on ultrasound attenuation imaging is not influenced by liver fibrosis.

AIM: Recently, a new technique using attenuation imaging (ATI) was developed to diagnose hepatic steatosis. The aim of this study was to investigate whether ATI for the evaluation of hepatic steatosis is influenced by liver fibrosis. METHODS: A total of 328 patients with chronic liver disease were enrolled to study the associations between histological hepatic steatosis or liver fibrosis and ATI findings. The interaction between liver fibrosis and ATI was also analyzed. RESULTS: Median ATI values according to steatosis grade and fibrosis stage increased in line with the progression of liver steatosis (p < 0.001) and fibrosis (p < 0.05). However, in each steatosis grade, ATI values according to fibrosis stage were not significantly increased. In multiple regression analyses for assessment of the effect of their interaction, the p values for fibrosis stage, steatosis grade, and fibrosis stage × steatosis grade were 0.096, <0.001, and 0.077, respectively. Variance inflation factor values for fibrosis stage, steatosis grade, and fibrosis stage × steatosis grade were 1.079, 1.094, and 1.074, respectively. CONCLUSION: Attenuation imaging values are not influenced by liver fibrosis.

A Pre-Release Algorithm With a Confidence Map for Estimating the Attenuation Coefficient for Liver Fat Quantification.

OBJECTIVES: To compare the estimates of attenuation coefficient (AC) for liver fat quantification between 2 Ultrasound systems and to evaluate the quality measure of a pre-released software. METHODS: AC were obtained in 30 participants in this single-center IRB-approved, HIPAA compliant study. Images were obtained on the Philips Epiq Elite system using experimental software and the Canon Medical Systems Aplio i800 with released software. Five AC measurements were taken and the median and IQR/M were calculated. Region of interest placement was based on a confidence map. ROI was at the same depth and size for each system. The concordance was estimated using the Lin's concordance correlation coefficient (CCC), the r Pearson's correlation coefficient, the bias-correction factor (Cb), and the Bland-Altman method. RESULTS: The ACs varied from 0.45 to 1.0 dB/cm/MHz for the Philips system and 0.30 to 0.96 dB/cm/MHz for the Canon system. The CCC (95% CI) was 0.792 (0.666-0.918), Pearson's r was 0.839 with Cb of 0.944, and the mean difference was 0.03 (-0.101; 0.162) suggesting the 2 methods are considered to be in agreement. Based on a Philips confidence map to determine the best location for performing the measurements, a depth of 3.5 to 4.0 cm from the liver capsule was determined, which might be significantly different than that of the Canon system. CONCLUSIONS: Estimation of the AC of the 2 systems showed a high agreement, that is, a similar trend. Assessment of the placement of the measurement box based on the quality of the measurement might be different between the 2 systems.

Estimation of Tissue Attenuation from Ultrasonic B-Mode Images-Spectral-Log-Difference and Method-of-Moments Algorithms Compared.

We report on results from the comparison of two algorithms designed to estimate the attenuation coefficient from ultrasonic B-mode scans obtained from a numerical phantom simulating an ultrasound breast scan. It is well documented that this parameter significantly diverges between normal tissue and malignant lesions. To improve the diagnostic accuracy it is of great importance to devise and test algorithms that facilitate the accurate, low variance and spatially resolved estimation of the tissue's attenuation properties. A numerical phantom is realized using k-Wave, which is an open source Matlab toolbox for the time-domain simulation of acoustic wave fields that facilitates both linear and nonlinear wave propagation in homogeneous and heterogeneous tissue, as compared to strictly linear ultrasound simulation tools like Field II. k-Wave allows to simulate arbitrary distributions, resolved down to single voxel sizes, of parameters including the speed of sound, mass density, scattering strength and to include power law acoustic absorption necessary for simulation tasks in medical diagnostic ultrasound. We analyze the properties and the attainable accuracy of both the spectral-log-difference technique, and a statistical moments based approach and compare the results to known reference values from the sound field simulation.

[Research Progress of Quantitative Ultrasound Assessment of Liver Steatosis in Non-alcoholic Fatty Liver Disease].

The incidence of non-alcoholic fatty liver disease(NAFLD)keeps on rise.Without intervention,it may develop to steatohepatitis,cirrhosis,and even hepatocellular carcinoma.Liver biopsy,the gold standard for evaluating the steatosis severity of NAFLD,is invasive and unsuitable for large-scale screening.In recent years,magnetic resonance imaging(MRI)-related examinations have been used as a gold standard only second to liver biopsy,which still have disadvantages in large-scale application.Ultrasound has the advantages of simple operation,low cost,and safety,and may become an important method for accessing NALFD.This review summarizes the current studies about the diagnosis of liver steatosis by quantitative ultrasound assessment,including controlled attenuation parameters,attenuation imaging,ultrasonic liver/kidney intensity ratio and liver attenuation rate,and integrated backscatter.

Attenuation imaging based on ultrasound technology for assessment of hepatic steatosis: A comparison with magnetic resonance imaging-determined proton density fat fraction.

AIM: A new method has recently been developed for diagnosing hepatic steatosis based on attenuation measurement using ultrasound. We investigated the ability of attenuation imaging (ATI) to detect steatosis that was identified by proton density fat fraction (PDFF) on magnetic resonance imaging (MRI) in patients with chronic liver disease. METHODS: A total of 119 patients with chronic liver disease (non-B, non-C) were analyzed. The relationship between ATI values and steatosis grades determined by PDFF was evaluated. Additionally, the diagnostic ability of ATI was evaluated using receiver operating characteristic curve analysis, and the correlation between ATI values and PDFF values was determined. RESULTS: The ATI values of steatosis grades 0, 1, 2, and 3 were 0.55, 0.61, 0.74, and 0.84 dB/cm/MHz, respectively (P < 0.001). There was a statistically significant trend of higher ATI values with higher steatosis grades (P < 0.001). The correlation coefficient (r) between PDFF values and ATI values was 0.70 (95% confidence interval [CI] 0.59-0.78; P < 0.001), corresponding to a strong relationship. The diagnostic ability of ATI for steatosis grades ≥1, ≥2, and 3, as determined by PDFF, were 0.81 (95% CI 0.73-0.89), 0.87 (95% CI 0.79-0.96), and 0.94 (95% CI 0.89-0.98), respectively. The r between PDFF values and ATI values was 0.49 (95% CI 0.31-0.63; P < 0.001) for patients with mild or no steatosis (grade ≤1), and 0.75 (95% CI 0.57-0.86; P < 0.001) for obese patients (body mass index ≥25 kg/m2 ). CONCLUSION: ATI values had an excellent diagnostic ability to detect hepatic steatosis.

Diagnostic performance of two-dimensional shear wave elastography and attenuation imaging for fibrosis and steatosis assessment in chronic liver disease.

PURPOSE: We investigated the diagnostic performance of two-dimensional shear wave elastography (2D-SWE) and attenuation imaging (ATI) in detecting fibrosis and steatosis in patients with chronic liver disease (CLD), comparing them with established methods. METHODS: In 190 patients with CLD, 2D-SWE and vibration-controlled transient elastography (VCTE) were used for liver stiffness measurement (LSM), and ATI and controlled attenuation parameter (CAP) were used for steatosis quantification. The correlations between these new and established methods were analyzed. RESULTS: Significant correlations were found between 2D-SWE and VCTE (r = 0.78, P < 0.001), and between ATI and CAP (r = 0.70, P < 0.001). Liver stiffness tended to be lower with 2D-SWE compared with that with VCTE, especially in cases with higher LSM, and ATI was less influenced by skin-capsular distance than CAP. Area under the receiver-operating characteristics curves (AUCs) and optimal cut-offs of 2D-SWE for diagnosing liver fibrosis stages F2, F3, and F4 were 0.73 (8.7 kPa), 0.79 (9.1 kPa), and 0.88 (11.6 kPa), respectively. The AUCs and optimal cut-offs of ATI for diagnosing hepatic steatosis grades S1, S2, and S3 were 0.91 (0.66 dB/cm/MHz), 0.80 (0.79 dB/cm/MHz), and 0.88 (0.86 dB/cm/MHz), respectively. A subgroup analysis of 86 patients with metabolic dysfunction-associated steatotic liver disease also demonstrated good performance for 2D-SWE and ATI. CONCLUSION: 2D-SWE and ATI performed comparably with conventional VCTE and CAP in evaluating CLD, offering reliable alternatives for diagnosing liver fibrosis and steatosis.

Role of multiparametric US in the preoperative assessment of hepatic parenchyma in patients with liver tumors.

OBJECTIVES: The aim of this study was to evaluate the diagnostic performance of shear wave elastography (SWE), shear wave dispersion (SWD), and attenuation imaging (ATI) in assessment of hepatic parenchyma in patients with liver tumors before resection. METHODS: Patients with liver tumors were prospectively enrolled in this study. All participants underwent SWE, SWD, and ATI examinations. Fibrosis stage, necroinflammatory activity and hepatic steatosis grade were determined histopathologically. We evaluated the stability of ATI, SWE and SWD examinations. Multivariable linear regression analyses were conducted to determine the determinant factors for SWE, SWD, attenuation coefficient (AC) values. A receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic performance of multiparametric US (ultrasond). RESULTS: A total of 280 participants were enrolled in this study. TG (triglyceride) and steatosis for AC value were significant determinant factors. PLT (platelet), PT (prothrombin time), GGT (glutamyl transpeptidase), and fibrosis stage for SWE value were significant determinant factors. PLT, fibrosis stage and inflammation activity for SWD value were significant determinant factors. AC value was correlated with hepatic steatosis. Both SWE and SWD values were correlated with fibrosis stage, inflammation activity, respectively. The area under the ROC (AUROC) curve of ATI for predicting hepatic steatosis grade were 0.910(≥ S1), 0.927(≥ S2), 0.962(= S3), respectively. The AUROC curve of SWE for predicting fibrosis stage were 0.923(≥ S1), 0.934(≥ S2), 0.930(≥ S3), 0.895(= S4), respectively. The AUROC curve of SWD for predicting fibrosis stage were 0.858(≥ S1), 0.886(≥ S2), 0.866(≥ S1) (≥ S3), 0.825(= S4). The AUROC curve of SWE for predicting inflammation activity were 0.846(≥ G1), 0.724(≥ G2), 0.787 (≥ G3), respectively. The AUROC curve of SWD for predicting inflammation activity were 0.777(≥ G1), 0.727(≥ G2), 0.803 (≥ G3), respectively. CONCLUSIONS: For patients with liver tumors, ATI technology showed excellent feasibility and diagnostic performance for detecting and grading hepatic steatosis, SWE was more accurate in detecting fibrosis stage than SWD, SWD was not superior to SWE in detecting inflammation activity.

Hepatic steatosis: Qualitative and quantitative sonographic assessment in comparison to histology.

Introduction: Globally, B-mode ultrasound is the most common modality used for the diagnosis of hepatic steatosis. We aimed to assess the correlation between qualitative liver ultrasound parameters, attenuation imaging (ATI) and histopathology-diagnosed steatosis grade obtained from liver biopsy. Our secondary aim was to examine the interobserver variability of qualitative ultrasound features. Methods: A retrospective cohort study was performed which included adult patients (age ≥ 18 years) who had same-day liver ultrasound, ATI and liver biopsy for grading hepatic steatosis severity between 2018 and 2022. The qualitative US features for hepatic steatosis were independently scored by three radiologists and interobserver variability was examined. Histologic steatosis grade, ATI and qualitative ultrasound parameters were compared. Results: Ninety patients were included; 67% female with a median age of 54 (IQR 39-65) years. The radiologist's overall impression had the highest correlation (very strongly correlated) with histologic steatosis grade (r = 0.82, P < 0.001). ATI coefficient and all qualitative ultrasound B-mode features except for liver echotexture and focal fat sparing were strongly correlated with histologic steatosis grade (r ≥ 0.70, P < 0.001). Most qualitative ultrasound features had good agreement between observers (Kappa statistic 0.61-1.0, P < 0.001), (Kendall coefficient 0.92, P < 0.001). Conclusion: The examined qualitative ultrasound parameters and ATI had good-excellent performance for diagnosing clinically significant hepatic steatosis; however, the radiologist's overall impression had the best correlation with histologic steatosis grade. Our findings suggest an ongoing role for qualitative liver ultrasound assessment of hepatic steatosis despite the emergence of newer quantitative measures.

Pulse-echo ultrasound attenuation tomography.

Objective.We present the first fully two-dimensional attenuation imaging technique developed for pulse-echo ultrasound systems. Unlike state-of-the-art techniques, which use line-by-line acquisitions, our method uses steered emissions to constrain attenuation values at each location with multiple crossing wave paths, essential to resolve the spatial variations of this tissue property.Approach.At every location, we compute normalized cross-correlations between the beamformed images that are obtained from emissions at different steering angles. We demonstrate that their log-amplitudes provide the changes between attenuation-induced amplitude losses undergone by the different incident waves. This allows us to formulate a linear tomographic problem, which we efficiently solve via a Tikhonov-regularized least-squares approach.Main results.The performance of our tomography technique is first validated in numerical examples and then experimentally demonstrated in custom-made tissue-mimicking phantoms with inclusions of varying size, echogenicity, and attenuation. We show that this technique is particularly good at resolving lateral variations in tissue attenuation and remains accurate in media with varying echogenicity.Significance.Based on a similar principle, this method can be easily combined with computed ultrasound tomography in echo mode for speed-of-sound imaging, paving the way towards a multi-modal ultrasound tomography framework characterizing multiple acoustic tissue properties simultaneously.

Head-to-head comparison of three different US-based quantitative parameters for hepatic steatosis assessment: a prospective study.

PURPOSE: To evaluate the diagnostic performance of attenuation coefficient (AC), hepato-renal index (HRI) and controlled attenuation parameter (CAP) in quantitative assessment of hepatic steatosis by employing histopathology as reference standard. METHODS: Participants with suspected metabolic-associated fatty liver disease (MAFLD) who underwent US-based parameter examinations and liver biopsy were prospectively recruited. The distributions of US parameters across different grades of steatosis were calculated, and diagnostic performance was determined based on the areas under the receiver operating characteristic curve (AUC). RESULTS: A total of 73 participants were included, with hepatic steatosis grades S0, S1, S2, and S3 distributed as follows: 13, 20, 27, and 13 respectively. The correlation coefficients for CAP, AC, and HRI ranged from 0.67 to 0.74. AC and HRI showed a strong correlation with steatosis grade. The AUC for CAP and AC in diagnosing steatosis ≥ S1 were significantly higher at 0.99 and 0.98 compared to HRI's value. For diagnosing steatosis ≥ S2, the AUC of CAP (AUC: 0.85) was lower than that of AC (AUC: 0.94), and HRI (AUC: 0.94). Similarly for diagnosing steatosis S3, the AUC of CAP (AUC: 0.68) was lower than that of AC (AUC: 0.88), and HRI (AUC: 0.88). CONCLUSION: The AC and HRI values increased with the progression of hepatic steatosis grade, while CAP increased from S0 to S2 but not from S2 to S3. For mild steatosis diagnosis, CAP and AC showed superior diagnostic performance compared to HRI, while AC and HRI were more advantageous in differentiating moderate and severe steatosis.

WFUMB Guidelines/Guidance on Liver Multiparametric Ultrasound. Part 2: Guidance on Liver Fat Quantification.

The World Federation for Ultrasound in Medicine and Biology (WFUMB) has promoted the development of this document on multiparametric ultrasound. Part 2 is a guidance on the use of the available tools for the quantification of liver fat content with ultrasound. These are attenuation coefficient, backscatter coefficient, and speed of sound. All of them use the raw data of the ultrasound beam to estimate liver fat content. This guidance has the aim of helping the reader in understanding how they work and interpret the results. Confounding factors are discussed and a standardized protocol for measurement acquisition is suggested to mitigate them. The recommendations were based on published studies and experts' opinion but were not formally graded because the body of evidence remained low at the time of drafting this document.

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.