Evaluation of Non-alcoholic Fatty Liver Disease Using Acoustic Radiation Force Impulse Imaging Elastography in Rat Models

The aim of this study is to evaluate the utility of acoustic radiation force impulse (ARFI) elastography for assessing hepatic fibrosis stage and non-alcoholic fatty liver disease (NAFLD) severity, as well as the relationship among hepatic histologic changes using shear wave velocity (SWV). Animal models with various degrees of NAFLD were established in 110 rats. The right liver lobe was processed and embedded in a fabricated gelatin solution (porcine skin). Liver mechanics were measured using SWV induced by acoustic radiation force. Among the histologic findings, liver elasticity could be used to differentiate normal rats from rats with simple steatosis (SS) as well as distinguish SS from non-alcoholic steatohepatitis (NASH), with areas under the receiver operating characteristic curves (AUROC) of 0.963 (95% confidence interval = 0.871–0.973) and 0.882 (95% confidence interval = 0.807–0.956), respectively. For NAFLD rats, the diagnostic performance of ARFI elastography in predicting significant fibrosis (F ≥ 2) had an AUROC of 0.963. For evaluating steatosis severity, we found a progressive increase in ARFI velocity proportional to steatotic severity in NAFLD rat models, but we observed no significant differences for steatotic severity after excluding the rats with fibrosis. ARFI elastography may be used to differentiate among degrees of severity of NAFLD and hepatic fibrotic stages in NAFLD rat models.     

Acoustic Radiation Force Impulse and Conventional Ultrasound in the Prediction of Cirrhosis Complicating Fatty Liver: Does Body Mass Index Independently Alter the Results?

We investigated whether ultrasound (US) could quantify steatosis and fibrosis in non-alcoholic fatty liver disease (NAFLD). Estimates of fat by gray-scale, hepatorenal index (HRI) and fibrosis by acoustic radiation force impulse (ARFI) were made using the interquartile range (IQR)/median for ARFI quality. Biopsy was the gold standard. US fat assessment correlated with histologic grade and predicted steatosis. HRI predicted steatosis but did not improve accuracy. ARFI of good quality was highly sensitive toward severe fibrosis. The median ARFI value depended linearly on body mass index (BMI). Poor quality ARFI data had higher histologic steatosis, leading to higher mean steatosis grades in rejected data (p = 0.018). The ARFI quality cut with IQR/median >0.15 or >0.3 excluded many more patients with severe steatosis versus normal, influenced by increasing BMI. By combining the baseline US with ARFI, patients can be concurrently diagnosed for steatosis and fibrosis, two of the key pathologies of NAFLD and non-alcoholic steatohepatitis (NASH). However, severe steatosis and high BMI may falsely alter ARFI results.     

Factors Which Influence the Accuracy of Acoustic Radiation Force Impulse (ARFI) Elastography for the Diagnosis of Liver Fibrosis in Patients with Chronic Hepatitis C

Our study tried to identify the factors associated with discordance between liver stiffness values assessed by acoustic radiation force impulse (ARFI) elastography and histologic fibrosis in 106 chronic hepatitis C patients. Liver biopsy (LB) and ARFI measurements were performed in the same session. A discordance of at least two stages of fibrosis in the Metavir scoring system between ARFI results and LB was defined as significant. The performance of ARFI elastography was assessed using the following cut-offs: F1-1.19 m/s, F2-1.34 m/s, F3-1.55 m/s and F4-1.80 m/s. Discordance of at least two stages of fibrosis between ARFI results and histologic assessment were observed in 31.7% of the patients. In an univariate analysis, female sex (p = 0.004), interquartile range interval (IQR) ≥30% (p = 0.04), high alanine aminotransferases (p = 0.008) and high aspartate aminotransferases levels (p = 0.003) were associated with discordances. In a multivariate analysis, the female sex (p = 0.006) and IQR ≥30% (p = 0.004) were associated with discordances. Therefore, IQR parameter should be used for ARFI measurements.     

Comparison of Acoustic Radiation Force Impulse Imaging and Transient Elastography for Non-invasive Assessment of Liver Fibrosis in Patients with Chronic Hepatitis B

The aims of this study were to compare the performance of acoustic radiation force impulse (ARFI) elastography and transient elastography (TE) in the assessment of liver fibrosis in patients with chronic hepatitis B and to evaluate the impact of elevated alanine transaminase levels on liver stiffness assessment using ARFI elastography. One hundred eighty consecutive patients with chronic hepatitis B were enrolled in this study and evaluated with respect to histologic and biochemical features. All patients underwent ARFI elastography and TE. ARFI elastography and TE correlated significantly with histologically assessed fibrosis (r = 0.599, p < 0.001, for ARFI elastography; r = 0.628, p < 0.001, for TE) and necro-inflammatory activity (r = 0.591, p < 0.001, for ARFI elastography; r = 0.616, p < 0.001, for TE). Areas under the receiver operating characteristic curves for ARFI elastography and TE were 0.764 and 0.813 (p = 0.302, ≥stage 2), 0.852 and 0.852 (p = 1.000, ≥stage 3) and 0.825 and 0.799 (p = 0.655, S = 4), respectively. The optimum cutoff values for ARFI elastography were 1.63 m/s for stage ≥2, 1.74 m/s for stage ≥3 and 2.00 m/s for stage 4 in patients for whom alanine transaminase levels were evaluated. The cutoff values decreased to 1.24 m/s for ≥ stage 2, 1.32 m/s for ≥ stage 3 and 1.41 m/s for stage 4 in patients with normal alanine transaminase levels. ARFI elastography may be a reliable method for diagnosing the stage of liver fibrosis with diagnostic performance similar to that of TE in patients with chronic hepatitis B. In addition, liver stiffness values obtained with ARFI elastography, like those obtained with TE, may be influenced by alanine transaminase levels.     

Shear Wave Elastography for Assessment of Steatohepatitis and Hepatic Fibrosis in Rat Models of Non-Alcoholic Fatty Liver Disease

The purpose of this study was to evaluate shear wave elastography (SWE) as a method for determining the severity of non-alcoholic fatty liver disease (NAFLD) and the stage of hepatic fibrosis, as well as the major determinants of liver elasticity among the various histologic and biomolecular changes associated with NAFLD. Rat NAFLD models with various degrees of NAFLD severity were created and imaged using SWE. The explanted livers were subjected to histopathologic evaluation and RNA expression analysis. Among the histologic and biomolecular findings, the fibrosis stage and the collagen RNA level were significant independent factors associated with liver elasticity (p < 0.001). Liver elasticity was effective in detecting non-alcoholic steatohepatitis (NASH) and in determining fibrosis stage, and the corresponding areas under the receiver operating characteristic curves were 0.963 and 0.927–0.997, respectively. In conclusion, SWE is a potential non-invasive method for the detection of NASH and staging of hepatic fibrosis in patients with NAFLD.     

Acoustic Radiation Force Impulse and Supersonic Shear Imaging Versus Transient Elastography for Liver Fibrosis Assessment

Our study compared three elastographic methods—transient elastography (TE), acoustic radiation force impulse (ARFI) imaging and supersonic shear imaging (SSI)—with respect to the feasibility of their use in liver fibrosis evaluation. We also compared the performance of ARFI imaging and SSI, with TE as the reference method. The study included 332 patients, with or without hepatopathies, in which liver stiffness was evaluated using TE, ARFI and SSI. Reliable measurements were defined as a median value of 10 (TE, ARFI imaging) or 5 (SSI) liver stiffness measurements with a success rate ≥60% and an interquartile range interval <30%. A significantly higher percentage of reliable measurements were obtained using ARFI than by using TE and SSI: 92.1% versus 72.2% (p < 0.0001) and 92.1% versus 71.3% (p < 0.0001). Higher body mass index and older age were significantly associated with inability to obtain reliable measurements of liver stiffness using TE and SSI. In 55.4% of patients, reliable liver stiffness measurements were obtained using all three elastographic methods, and ARFI imaging and TE were similarly accurate in diagnosing significant fibrosis and cirrhosis, with TE as the reference method.     

Accuracy of Controlled Attenuation Parameter and Liver Stiffness Measurement in Patients with Non-alcoholic Fatty Liver Disease

We evaluated the diagnostic accuracy of the controlled attenuation parameter (CAP) and liver stiffness measurements (LSM) measured with either an M or XL probe against liver biopsy (LB) in patients with non-alcoholic fatty liver disease (NAFLD). This study was a cross-sectional prospective study that included 179 NAFLD patients. With a cutoff value for CAP ≥345, we can exclude significant steatosis in 87% (79.4%–92.5%) of our population. With respect to the LSM, the highest accuracy was obtained for F ≥ F3 (area under the receiver operating characteristic curve [AUROC] = 0.98) and F = F4 (AUROC = 0.98). In a multivariable linear regression model, significant predictors influencing LSM were fibrosis stage (β = 2.6, p < 0.001) as a positive predictor and lobular inflammation (β = –0.68, p = 0.04) as a negative predictor, without significant influence after adjustment for CAP and probe type. We found that CAP is a satisfactory method for excluding advanced steatosis, while LSM is a good non-invasive marker for the exclusion of fibrosis.     

Noninvasive in vivo liver fibrosis evaluation using supersonic shear imaging: a clinical study on 113 hepatitis C virus patients

Supersonic shear imaging (SSI) has recently been demonstrated to be a repeatable and reproducible transient bidimensional elastography technique. We report a prospective clinical evaluation of the performances of SSI for liver fibrosis evaluation in 113 patients with hepatitis C virus (HCV) and a comparison with FibroScan (FS). Liver elasticity values using SSI and FS ranged from 4.50 kPa to 33.96 kPa and from 2.60 kPa to 46.50 kPa, respectively. Analysis of variance (ANOVA) shows a good agreement between fibrosis staging and elasticity assessment using SSI and FS (p < 10⁻⁵). The areas under receiver operating characteristic (ROC) curves for elasticity values assessed from SSI were 0.948, 0.962 and 0.968 for patients with predicted fibrosis levels F ≥ 2, F ≥ 3 and F = 4, respectively. These values are compared with FS area under the receiver operating characteristic curve (AUROC) of 0.846, 0.857 and 0.940, respectively. This comparison between ROC curves is particularly significant for mild and intermediate fibrosis levels. SSI appears to be a fast, simple and reliable method for noninvasive liver fibrosis evaluation.     

The relationship of serum uric acid with non-alcoholic fatty liver disease

Objectives

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological entity which is characterized by the presence of fat droplets in hepatocytes without alcohol consumption, representing a spectrum of hepatic injuries, ranging from simple steatosis (SS) to non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. In recent years, experimental and observational studies suggest a role for serum uric acid (SUA) in NAFLD. However, there are few reports investigating SUA in histologically proven NAFLD. The aim of the present study was to evaluate the relationship of SUA with liver histology in non-diabetic patients with NAFLD.

Design and methods

A total of 242 male patients with NAFLD (102 with NASH and 140 with SS) were included. Histopathological evaluation was carried out according to Kleiner's scoring scale. Hyperuricemia was diagnosed as SUA of more than 7 mg/dL.

Results

The prevalence of hyperuricemia was 33.4%. SUA levels in patients with NASH were significantly higher than those of SS (p = 0.035). Univariate and multivariate analyses both demonstrated that hyperuricemia had a significant association with younger age [OR (95%CI), 0.930 (0.884–0.979), p = 0.005], higher body mass index [OR (95%CI), 1.173 (1.059–1.301), p = 0.002] and hepatocellular ballooning [OR (95%CI), 1.678 (1.041–2.702), p = 0.033].

Conclusions

Hyperuricemia is a common finding in patients with NAFLD and is independently associated with early histological findings in this clinically relevant condition. Further longitudinal studies are needed to characterize the role of SUA in the natural history of NAFLD.     

Liver elasticity in NASH patients evaluated with real-time elastography (RTE)

Liver elasticity as assessed by real-time elastography (RTE) has been shown to be correlated to liver fibrosis in various chronic liver diseases. The aim of our study was to assess the RTE performance in the evaluation of liver fibrosis in nonalcoholic steatohepatitis (NASH), as well as the histopathologic variables determining the eventual discordance between the RTE-predicted and the biopsy-proven fibrosis. Fifty-two consecutive biopsy proven NASH patients and 20 controls were studied. Liver tissue elasticity measurements were performed using the Hitachi EUB-8500 sonographer and the EUP-L52 Linear (3–7 MHz) probe. RTE liver tissue mean elasticity (TME) values were calculated and correlated to the histologic fibrosis, activity and steatosis scores. A decrease in TME was observed with increasing fibrosis (r = −0.75). Similarly, TME varied together consistently with steatosis (r = −0.3). In contrast, TME did not show any correlation with the severity of inflammation. Multiple regression analysis showed that fibrosis was the only variable able to significantly (p < 0.0001) modify TME values. The diagnostic accuracy of TME measurement for F > 0 evaluated by AUC-ROC analysis was 0.86. The diagnostic accuracy of TME measurement for F ≥ 2 was 0.92. We suggest that RTE could be used as a complementary imaging method to evaluate liver fibrosis in NASH patients. Future studies of larger patient cohorts are necessary for the validation of the technique.     

The Influence of Food Intake on Liver Stiffness Values Assessed by Acoustic Radiation Force Impulse Elastography—Preliminary Results

The present study assessed the influence of food intake on acoustic radiation force impulse elastography (ARFI) measurements. Seventy-three healthy volunteers were included: 57 subjects in the study group (on whom ARFI measurements were performed first in fasting condition, followed by measurements made 1h and 3h after food intake); and 16 subjects in the control group (on whom ARFI measurements were performed 3 times during a 3-h interval without eating). All subjects included in the study group received the same standard solid meal. In the study group, the mean liver stiffness (LS) values by ARFI increased significantly 1 h after food intake (1.51 ± 0.40 m/s vs. 1.27 ± 0.23, p = 0.003), but 3 h after the meal the differences were no longer significant (1.46 ± 0.51 vs. 1.27 ± 0.23, p = 0.06). In the control group, the mean LS values were similar in all 3 measurements. In conclusion, food intake significantly increased the LS values, thus ARFI measurements should be performed in fasting conditions.     

Factors that Influence Kidney Shear Wave Speed Assessed by Acoustic Radiation Force Impulse Elastography in Patients without Kidney Pathology

Our aim was to assess kidney shear wave speed by means of acoustic radiation force impulse (ARFI) elastography in patients without kidney pathology (“normal” patients) and to identify the factors that influence it. We analyzed 91 “normal” patients in whom kidney shear wave speed was assessed by means of ARFI elastography. Five valid ARFI elastographic measurements were obtained in all “normal” patients in both kidneys. In univariate analysis, age (r = −0.370, p = 0.003), gender (female vs. male, r = −0.305, p = 0.003) and measurement depth (r = −0.285, p = 0.01) were significantly correlated with kidney shear wave speed values assessed by ARFI elastography, whereas body mass index, kidney length and renal parenchyma thickness were not correlated. In multivariate analysis, only age (p = 0.006) and gender (p = 0.03) were significantly correlated with kidney shear wave speed values. In conclusion, kidney shear wave speed values assessed by ARFI elastography in “normal” patients are influenced mainly by age and gender and less by measurement depth.     

声辐射力脉冲成像定量评价非酒精性脂肪性肝病与病理对照研究

目的 本研究应用声脉冲辐射力成像技术(ARFI)对非酒精性脂肪性肝病(NAFLD)患者进行检测和分析,探讨该技术在无创定量评价NAFLD的临床应用价值.方法 对67例NAFLD患者应用ARFI技术对肝脏的实时超声弹性进行测量,所有患者均进行超声引导下肝脏穿刺活检,以病理结果为金标准,对肝脏的ARFI测值与肝脏脂肪变性、小叶内炎症及肝纤维化程度关系进行统计分析.结果 NAFLD患者不同脂肪变性和小叶内炎症程度间ARFI测值差异无统计学意义(P>0.05),肝纤维化分期为S0~S4期的ARFI测值分别为(1.18±0.28)m/s,(1.25±0.31)m/s,(1.44±0.52)m/s,(1.54±0.50)m/s和(1.86±0.73)m/s,组间比较差异具有统计学意义(P<0.05).肝脏ARFI测值与肝纤维化分期存在相关性,相关系数为0.42(P<0.001).ARFI技术诊断NAFLD肝纤维化S≥1,S≥2,S≥3和S=4的受试者工作特征曲线下面积分别为0.631、0.714、0.765和0.853.结论 声脉冲辐射力成像技术作为一种实时超声弹性成像技术,可较准确的无创定量评价NAFLD肝纤维化程度,具有良好的临床应用前景.     

High NAFLD fibrosis score in non-alcoholic fatty liver disease as a predictor of carotid plaque development: a retrospective cohort study based on regular health check-up data in China

PurposesThere is increasing concern regarding cardiovascular risk in non-alcoholic fatty liver disease (NAFLD) patients with liver fibrosis. This study aims: (1) to assess the association between NAFLD and liver fibrosis status and the development of carotid plaque (CP), and (2) to identify CP risk factors among general population with different baseline NAFLD and liver fibrosis status.MethodsThis retrospective cohort study included 14,288 adult participants who went for regular health check-ups between 2014 and 2019, in one hospital in Zhejiang, China. NAFLD was diagnosed by abdominal ultrasound and the NAFLD fibrosis score (NFS) was calculated to reflect the extent of liver fibrosis. Cox proportional hazards analyses were applied to assess the risk of CP development across groups with different baseline NAFLD and NFS status.ResultsNAFLD participants with high NFS had higher risk of CP compared to non-NAFLD participants (adjusted hazard ratio 1.68, 95% confidence interval [CI] 1.43–1.96, p < .001). Progression from NAFLD free and NAFLD with low NFS to NAFLD with high NFS are associated with 1.56-fold (95% CI 1.21–2.01, p = .001) and 1.43-fold (95% CI 1.11-1.84, p = .006) increased risk of CP, respectively. Risk factors associated with CP vary based on baseline NAFLD and NFS status. Among NAFLD participants with high NFS, hypertension is the only significant risk factor after adjustment for other potential influencing factors.ConclusionsNAFLD and liver fibrosis status can be an independent predictor for CP development regardless of metabolic abnormalities. Hypertension is a major risk factor for CP development among NAFLD patients with high NFS.

KEY MESSAGES

• Non-alcoholic fatty liver disease (NAFLD) and liver fibrosis status can be an independent predictor for development of carotid plaque.
• Progression from NAFLD free and NAFLD with low NAFLD fibrosis score (NFS) to NAFLD with high NFS are associated with increased risk of carotid plaque.
• Risk factors associated with carotid plaque vary based on baseline NAFLD and NFS status, and hypertension plays the most important role among patients with NAFLD and high NFS.

     

Prospective Comparison of the Diagnostic Performance of Magnetic Resonance Elastography with Acoustic Radiation Force Impulse Elastography for Pre-operative Staging of Hepatic Fibrosis in Patients with Hepatocellular Carcinoma

The purpose of this study was to compare the diagnostic accuracy of magnetic resonance (MR) elastography with that of acoustic radiation force impulse (ARFI) elastography for pre-operative staging of hepatic fibrosis in patients with hepatocellular carcinoma. We prospectively enrolled 77 patients who were scheduled to undergo hepatectomy for hepatocellular carcinoma. Pre-operative MRE and ARFI elastography examinations were performed on the same day, and liver stiffness/velocity values were determined. Fibrosis stage and necro-inflammatory activity of resected specimens were determined histopathologically using the METAVIR scoring system. Correlations between MRE and ARFI elastography findings and histologic findings were determined by receiver operating characteristic (ROC) analysis. Correlation of MRE was excellent and correlation of ARFI elastography was good with fibrosis stage. MRE had better diagnostic performance than ARFI elastography in estimating substantial fibrosis (F2), severe fibrosis (F3) and cirrhosis (F4). The optimal cutoff value and the area under the ROC curve (AUROC) were determined using ROC curve analysis. The highest Youden index was used as a criterion for selecting the optimal cutoff value. ROC analysis revealed that MRE discriminated advanced stages of fibrosis (F?≥?2) well in patients with hepatocellular carcinoma at a cutoff value of 3.0?kPa with an AUROC value of 0.93, and ARFI elastography did so at a cutoff value of 1.77?m/s with an AUROC value of 0.81 for predicting advanced stages of fibrosis (F?≥?2). In conclusion, MRE is a more accurate imaging modality than ARFI elastography in estimating advanced stages of fibrosis and cirrhosis.     

Liver fibrosis: noninvasive assessment using supersonic shear imaging and FIB4 index in patients with non-alcoholic fatty liver disease

Purpose

Shear wave elastography (SWE) has been validated in chronic hepatitis C and B; however, limited data are available in non-alcoholic fatty liver disease (NAFLD). This study aimed to evaluate the accuracy of SWE and FIB4 index for the diagnosis of fibrosis in a cohort of consecutive patients with biopsy-proven NAFLD, and to evaluate the effects of other histologic parameters on SWE measurement.

Methods

Written informed consent was obtained from all patients, and this study was approved by our internal review board and ethics committee. Seventy-one patients with histologically proven NAFLD (mean age 50.8 years ± 15.7) were examined. All patients underwent SWE (Aixplorer?; SuperSonic Imagine) and FIB4 index (based on age, aspartate aminotransferase and alanine aminotransferase levels, and platelet counts) measurements. SWE measurements were compared with the histologic features based on the NAFLD activity score and FIB4 index.

Results

The area under the ROC curve for the diagnosis of hepatic fibrosis stage 3 or higher was 0.821 (optimal cut-off value 13.1 kPa, sensitivity 62.5%, specificity 57.4%) for SWE and 0.822 (optimal cut-off value 1.41, sensitivity 71.9%, specificity 53.9%) for FIB4 index. The median liver stiffness values measured using SWE showed a stepwise increase with increasing hepatic fibrosis stage (P < 0.001), inflammation score (P = 0.018), and ballooning score (P < 0.001), and showed a stepwise decrease with increasing hepatic steatosis stage (P = 0.046).

Conclusions

SWE and FIB4 index are useful noninvasive tools for estimating the severity of fibrosis in NAFLD patients. However, the presence of severe steatosis may affect the liver stiffness measurement, resulting in underestimations of liver fibrosis.

     

Diagnostic Performance of 2-D Shear-Wave Elastography with Propagation Maps and Attenuation Imaging in Patients with Non-Alcoholic Fatty Liver Disease

We aimed to investigate the diagnostic performance of new 2-D shear-wave elastography (SWE) with propagation maps and attenuation imaging (ATI) for quantification of fibrosis and steatosis in non-alcoholic fatty liver disease (NAFLD). Consecutive patients with NAFLD and healthy volunteers underwent liver stiffness measurement and steatosis quantification by means of vibration-controlled transient elastography coupled with the controlled attenuation parameter as the reference and by 2-D shear-wave elastography (2-D-SWE) with propagation maps and ATI as the investigational methods. We included 232 participants (164 in the NAFLD group and 68 in the healthy control group): 51.7%/49.3% women/men; mean age, 54.2 ± 15.2 y; mean body mass index, 29.4 ± 6.5 kg/m². Significant correlations were found between 2-D-SWE and vibration-controlled transient elastography (r = 0.71, p < 0.0001) and between ATI and the controlled attenuation parameter (r = 0.72, p < 0.0001). NAFLD-specific 2-D-SWE liver stiffness measurement cutoffs were as follows—F ≥ 2: 7.9 kPa (area under the curve [AUC] = 0.91); F ≥ 3: 10 kPa (AUC = 0.92); and F = 4: 11.4 kPa (AUC = 0.95). For steatosis, the best cutoffs by ATI were as follows—S1 = 0.73 dB/cm/MHz (AUC = 0.86); S2 = 0.76 dB/cm/MHz (AUC = 0.86); and S3 = 0.80 dB/cm/MHz (AUC = 0.83). According to Baveno VI criteria, the optimal 2-D-SWE liver stiffness measurement for diagnosing liver cirrhosis is 15.5 kPa (AUC = 0.94), and for ruling out compensated advanced chronic liver disease it is 9.2 kPa (AUC = 0.92). To conclude, 2-D-SWE with propagation maps and ATI is reliable for quantification of liver fibrosis and steatosis in patients with NAFLD.     

Comparison of Acoustic Structure Quantification,Transient Elastography (FibroScan) and Histology in Patients with Chronic Hepatitis B and without Moderate to Severe Hepatic Steatosis

The purpose of this study was to compare acoustic structure quantification (ASQ) with transient elastography for staging liver fibrosis. One hundred eighty-two patients with chronic hepatitis B and without moderate to severe hepatic steatosis scheduled for liver biopsy underwent ASQ and transient elastography examinations. All ASQ parameters, including total mode, total average, red mode, red average, red standard deviation, blue mode, blue average, blue standard deviation and focal disturbance (FD) ratio and liver stiffness obtained via transient elastography were found to correlate with fibrosis stage (Spearman's r?=?0.783, 0.791, 0.750, 0.771, 0.544, 0.718, 0.691, 0.439, 0.815 and 0.814, respectively; all p values < 0.001). Among the ASQ parameters, the FD ratio had the highest correlation with the stage of fibrosis. The areas under the receiver operating characteristic curves (AUCs) of FD ratio and liver stiffness were 0.911 and 0.906 for F ≥ F1, 0.918 and 0.882 for F ≥ F2, 0.911 and 0.914 for F ≥ F3 and 0.926 and 0.978 for F?=?F4, respectively. There was no significant difference in AUCs between FD ratio and liver stiffness in predicting different stages of fibrosis (p?=?0.062–0.912). ASQ is a promising technique for assessing liver fibrosis in the absence of moderate to severe hepatic steatosis.     

Tissue Elasticity Quantification by Acoustic Radiation Force Impulse for the Assessment of Renal Allograft Function

Acoustic radiation force impulse (ARFI) quantification, a novel ultrasound-based elastography method, has been used to measure liver fibrosis. However, few studies have been performed on the use of ARFI quantification in kidney examinations. We evaluated renal allograft stiffness using ARFI quantification in patients with stable renal function (n = 52) and those with biopsy-proven allograft dysfunction (n = 50). ARFI quantification, given as shear wave velocity (SWV), was performed. The resistance index (RI) was calculated by pulsed-wave Doppler ultrasound, and clinical and laboratory data were collected. Morphologic changes in transplanted kidneys were diagnosed by an independent pathologist. Mean SWV was more significantly negatively correlated with estimated glomerular filtration rate (eGFR) (r = –0.657, p < 0.0001) than was RI (r = –0.429, p = 0.0004) in transplanted kidneys. Receiver operating characteristic curve analysis revealed that the sensitivity and specificity of quantitative ultrasound in the diagnosis of renal allograft dysfunction were 72.0% and 86.5% (cutoff value = 2.625), respectively. The latter values were better than those of RI, which were 62.0% and 69.2% (cutoff value = 0.625), respectively. The coefficient of variation for repeat SWV measurements of the middle part of transplanted kidney was 8.64%, and inter-observer agreement on SWV was good (Bland-Altman method, ICC = 0.890). In conclusion, tissue elasticity quantification by ARFI is more accurate than the RI in diagnosing renal allograft function.     

Comparison Between Different Manufacturers’ 2-D and Point Shear Wave Elastography Techniques in Staging Liver Fibrosis in Chronic Liver Disease Using Liver Biopsy as the Reference Standard: A Prospective Study

The purpose of this study was to assess the utility of 2-D shear wave elastography (SWE) in assessing liver fibrosis in patients with chronic liver disease by comparing its performance with that of point shear wave elastography (pSWE) using liver histological staging as the reference standard. In this ethics committee-approved, single-institution prospective study, pSWE and 2-D SWE velocity measurements were obtained in 121 adult patients (age: 18–70 y, median: 45 y) immediately before a liver biopsy for chronic liver disease. Shear wave velocity (SWV) and Ishak scores were compared using the Kruskal–Wallis test, Spearman's correlation and receiver operating characteristic (ROC) curve analysis. Youden's index was used to determine the optimal cutoff point. There was no technical failure using pSWE and 2-D SWE. The mean difference for SWV between pSWE and 2-D SWE was 0.0223 (limits of agreement: –1.1009, 1.1145). Values for both pSWE and 2-D SWE were significantly correlated with fibrosis stage (Spearman's ρ = 0.606, p < 0.0001; ρ = 0.722, p < 0.001 respectively). The area under the ROC curve differentiating F ≥3 was 0.855 (95% confidence interval: 0.778–0.932) for pSWE and 0.884 (95% CI: 0.817–0.951) for 2-D SWE. The AUC for differentiating F ≥5 was 0.890 (95% CI: 0.826–0.954) for pSWE and 0.926 (95% CI: 0.88–0.973) for 2-D SWE. This study indicates that 2-D SWE provides feasible and accurate assessment of liver fibrosis, comparable to that provided by pSWE from two different manufacturers’ machines.