Acoustic radiation force impulse predicts long-term outcomes in a large-scale cohort:High liver cancer,low comorbidity in hepatitis B virus

BACKGROUND Acoustic radiation force impulse(ARFI)is used to measure liver fibrosis and predict outcomes.The performance of elastography in assessment of fibrosis is poorer in hepatitis B virus(HBV)than in other etiologies of chronic liver disease.AIM To evaluate the performance of ARFI in long-term outcome prediction among different etiologies of chronic liver disease.METHODS Consecutive patients who received an ARFI study between 2011 and 2018 were enrolled.After excluding dual infection,alcoholism,autoimmune hepatitis,and others with incomplete data,this retrospective cohort were divided into hepatitis B(HBV,n=1064),hepatitis C(HCV,n=507),and non-HBV,non-HCV(NBNC,n=391)groups.The indexed cases were linked to cancer registration(1987-2020)and national mortality databases.The differences in morbidity and mortality among the groups were analyzed.RESULTS At the enrollment,the HBV group showed more males(77.5%),a higher prevalence of prediagnosed hepatocellular carcinoma(HCC),and a lower prevalence of comorbidities than the other groups(P<0.001).The HCV group was older and had a lower platelet count and higher ARFI score than the other groups(P<0.001).The NBNC group showed a higher body mass index and platelet count,a higher prevalence of pre-diagnosed non-HCC cancers(P<0.001),especially breast cancer,and a lower prevalence of cirrhosis.Male gender,ARFI score,and HBV were independent predictors of HCC.The 5-year risk of HCC was 5.9%and 9.8%for those ARFI-graded with severe fibrosis and cirrhosis.ARFI alone had an area under the receiver operating characteristic curve(AUROC)of 0.742 for prediction of HCC in 5 years.AUROC increased to 0.828 after adding etiology,gender,age,and platelet score.No difference was found in mortality rate among the groups.CONCLUSION The HBV group showed a higher prevalence of HCC but lower comorbidity that made mortality similar among the groups.Those patients with ARFI-graded severe fibrosis or cirrhosis should receive regular surveillance.

Preliminary results of acoustic radiation force impulses (ARFI) ultrasound imaging of solid suspicious breast lesions

Objective： The aim of our study was to make the qualitative and quantitative analysis to breast lesions using acoustic radiation force impulses （ARFI）, and assess the diagnostic value of ARFI for differentiation between benign and malignant solid breast masses, meanwhile evaluate the influences of ARFI with breast imaging reporting and data system （BI-RADS） of suspicious masses. Methods： Seventy-five women with 86 breast lesions underwent conventional breast ultra- sound examination. Then B-mode BI-RADS features and assessments were recorded and standard breast US supplemented by ARFI elastographic examination were repeated. The data were recorded and analyzed as following： area ratio of breast lesion, the shear-wave velocity, the ratio of the shear-wave velocity between lesions and surrounding normal tissues, and according to the elastographic data reconsidered the BI-RADS category, all the results have been correlated with pathological results and make statistical evaluations of ARFI for differentiation between benign and malignant solid breast masses. Meantime our study has correlated the adjusted BI-RADS category of suspicious breast lesions with the pathological results and made assessment. Results： Thirty-eight patients were malignant breast carcinoma （31 invasive ductal carcinoma, 5 intraductal carcinoma in situ, 2 medullary carcinoma, 2 invasive Iobular carcinoma）, 48 patients were benign breast lesions （23 fibroadenoma, 12 benign nodular hyperplasia, 5 phyllodes tumor, 6 adenosis, 2 intraductal papilloma）. Underwent conventional breast ultrasound exam, 42 cases were BI-RADS category 3, 23 cases were BI-RADS category 4. When adding elastographic data, 46 cases were BI-RADS category 3 and 20 cases were BI-RADS category 4. Compared with pathological results showed for both the specificity of BIRADS features and the area under ROC curve has risen. Virtual touch tissue imaging （VTI） and virtual touch tissue quantification （VTQ） data showed the area ratio （AR） between elastographic lesions area and B-mode lesions area, SWV （maximal shear-wave velocity of lesions）, R-SWV （shear-wave velocity ratio between lesions and surrounding normal tissues） in benign breast lesions were lower than those in malignant lesions which has statistical significance and the cut-off point were 1.1,4.65 m/s, 5.18 respectively. Conclusion： The ARFI elastography can provide the reliable qualitative and quantitative analysis about hardness of breast lesions, supply the new BI-RADS category features to suspicious breast masses and serve as an effective diagnostic tool for differentiation between benign and malignant solid masses.

Evaluation of acoustic radiation force impulse imaging for determination of liver stiffness using transient elastography as a reference

AIM: To evaluate cut-off values and performance of acoustic radiation force impulse imaging (ARFI) using transient elastography [FibroScan■ (FS)] as a reference. METHODS: Six hundred and six patients were enrolled in this study.All patients underwent liver stiffness measurement with FS (FS-LS) and ARFI (with shear wave velocity quantification; ARFI-SWV) and the performance of ARFI in comparison to FS was determined. Sixtyeight patients underwent liver biopsy. RESULTS: Significantly higher success rates for the determination of liver stiffness were found using ARFI as compared to FS [604/606 (99.7%) vs 482/606 (79.5%); P < 0.001]. ARFI-SWV correlated significantly with FS-LS (r = 0.920, P < 0.001). ARFI-SWV increased significantly with the stage of fibrosis (1.09 ± 0.13 m/s for patients with no significant fibrosis (FS-LS < 7.6 kPa); 1.46 ± 0.27 m/s for patients with significant liver fibrosis (7.6 < FS-LS ≤ 13.0 kPa); and 2.55 ± 0.77 m/s for patients with liver cirrhosis (FS-LS > 13.0 kPa)). ARFI-SWV cut-off values were identified for no significant fibrosis (1.29 m/s; sensitivity 91.4% and specificity 92.6%) and for liver cirrhosis (1.60 m/s; sensitivity 92.3% and specificity 96.5%). The optimal cut-off value for predicting liver fibrosis (F ≥ 2) was 1.32 m/s (sensitivity 87.0% and specificity 80.0%) and for liver cirrhosis (F4) 1.62 m/s (sensitivity 100% and specificity 85.7%), for patients who underwent liver biopsy. An excellent inter-and intraobserver reproducibility was observed for ARFI-SWV determinations. CONCLUSION: An ARFI-SWV cut-off value of 1.29 m/s seems to be optimal for patients with no significant liver fibrosis and 1.60 m/s for patients with liver cirrhosis.

Acoustic radiation force impulse imaging for assessing liver fibrosis in alcoholic liver disease

AIM: To evaluate the performance of elastography by ultrasound with acoustic radiation force impulse(ARFI) in determining fibrosis stage in patients with alcoholic liver disease(ALD) undergoing alcoholic detoxification in relation to biopsy.METHODS: Eighty-three patients with ALD undergoing detoxification were prospectively enrolled. Each patient underwent ARFI imaging and a liver biopsy onthe same day. Fibrosis was staged according to the METAVIR scoring system. The median of 10 valid ARFI measurements was calculated for each patient.RESULTS: Sixty-nine males and thirteen females(one patient excluded due to insufficient biopsy size) were assessed with a mean alcohol consumption of 132.4 ± 128.8 standard drinks per week and mean cumulative year duration of 17.6 ± 9.5 years. Sensitivity and specificity were respectively 82.4%(0.70-0.95) and 83.3%(0.73-0.94)(AUROC = 0.87) for F ≥ 2 with a cut-off value of 1.63m/s; 82.4%(0.64-1.00) and 78.5%(0.69-0.89)(AUROC = 0.86) for F ≥ 3 with a cut-off value of 1.84m/s; and 92.3%(0.78-1.00] and 81.6%(0.72-0.90)(AUROC = 0.89) for F = 4 with a cut-off value of 1.94 m/s.CONCLUSION: ARFI is an accurate, non-invasive and easy method for assessing liver fibrosis in patients with ALD undergoing alcoholic detoxification.

Application of acoustic radiation force impulse imaging for the evaluation of focal liver lesion elasticity

BACKGROUND: Acoustic radiation force impulse (ARFI) imaging is a new elastography method for the evaluation of tissue stiffness. This study aims to evaluate the performance of ARFI in noninvasive assessment of the tissue stiffness of focal liver lesion (FLL) and to explore its potential value in the differential diagnosis of FLL. METHODS: ARFI was performed in 140 patients with 154 FLLs, which included 28 hemangiomas (ANGIs), 14 focal nodular hyperplasias (FNHs), 61 hepatocellular carcinomas (HCCs), 39 metastases and 12 cholangiocellular carcinomas (CCCs). Virtual touch tissue quantification (VTTQ) values were obtained, analyzed and compared. The area under the receiver operating characteristic curve (AUROC) and optimal cut-off values were obtained using a receiver operating characteristic (ROC) curve analysis to assess diagnostic performance. All cases were definitively diagnosed using histopathology, CT, MRI or contrast-enhanced ultrasound. RESULTS: The VTTQ median values of ANGI, FNH, HCC metastasis and CCC were 1.30, 1.80, 2.52, 3.08 and 3.89 m/s respectively. A significant increase in the VTTQ values of different lesions was observed: ANGI【FNH【HCC【metastasis 【CCC (P【0.001). The AUROC (95% CI) of VTTQ values was 0.94 (0.90-0.98) for ANGI, 0.91 (0.87-0.96) for malignant lesions and 0.87 (0.79-0.94) for CCC. The sensitivity and specificity for ANGI (86.5%, 89.3%, respectively), malignancy (81.3% 92.9%, respectively), and CCC (91.7%, 72.5%, respectively) were associated with VTTQ cut-off values of 1.76, 2.22 and 3.00 m/s respectively.CONCLUSIONS: ARFI can accurately and objectively assess the elasticity of lesions by obtaining the shear wave elastic value of FLL with VTTQ. Therefore, ARFI is a novel, simple, noninvasive and useful diagnostic method for the characterization of FLL.

Liver reserve function assessment by acoustic radiation force impulse imaging

AIM: To evaluate the utility of liver reserve function by acoustic radiation force impulse(ARFI) imaging in patients with liver tumors. METHODS: Seventy-six patients with liver tumors were enrolled in this study. Serum biochemical indexes, such as aminotransferase(ALT), aspartate aminotransferase(AST), serum albumin(ALB), total bilirubin(T-Bil), and other indicators were observed. Liver stiffness(LS) was measured by ARFI imaging, measurements were repeated 10 times, and the average value of the results was taken as the final LS value. Indocyanine green(ICG) retention was performed, and ICG-K and ICG-R15 were recorded. Child-Pugh(CP) scores were carried out based on patient's preoperative biochemical tests and physical condition. Correlations among CP scores,ICG-R15, ICG-K and LS values were observed and analyzed using either the Pearson correlation coefficient or the Spearman rank correlation coefficient. KruskalWallis test was used to compare LS values of CP scores, and the receiver-operator characteristic(ROC) curve was used to analyze liver reserve function assessment accuracy. RESULTS: LS in the ICG-R15 10%-20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant(2.19 ± 0.27 vs 1.59 ± 0.32, P < 0.01). LS in the ICG-R15 > 20% group was significantly higher than in the ICG-R15 < 10% group; and the difference was statistically significant(2.92 ± 0.29 vs 1.59 ± 0.32, P < 0.01). The LS value in patients with CP class A was lower than in patients with CP class B(1.57 ± 0.34 vs 1.86 ± 0.27, P < 0.05), while the LS value in patients with CP class B was lower than in patients with CP class C(1.86 ± 0.27 vs 2.47 ± 0.33, P < 0.01). LS was positively correlated with ICG-R15(r = 0.617, P < 0.01) and CP score(r = 0.772, P < 0.01). Meanwhile, LS was negatively correlated with ICG-K(r =-0.673, P < 0.01). AST, ALT and T-Bil were positively correlated with LS, while ALB was negatively correlated with LS(P < 0.05). The ROC curve revealed that the when the LS value was 2.34 m/s, the Youden index was at its highest point, sensitivity was 69.2% and specificity was 92.1%. CONCLUSION: For patients with liver tumors, ARFI imaging is a useful tool for assessing liver reserve function.

Primary biliary cirrhosis degree assessment by acoustic radiation force impulse imaging and hepatic fibrosis indicators

AIM: To evaluate the assessment of primary biliary cirrhosis degree by acoustic radiation force impulse imaging (ARFI) and hepatic fibrosis indicators. METHODS: One hundred and twenty patients who developed liver cirrhosis secondary to primary biliary cirrhosis were selected as the observation group, with the degree of patient liver cirrhosis graded by Child-Pugh (CP) score. Sixty healthy individuals were selected as the control group. The four indicators of hepatic fibrosis were detected in all research objects, including hyaluronic acid (HA), laminin (LN), type III collagen (PC III), and type IV collagen (IV-C). The liver parenchyma hardness value (LS) was then measured by ARFI technique. LS and the four indicators of liver fibrosis (HA, LN, PC III, and IV-C) were observed in different grade CP scores. The diagnostic value of LS and the four indicators of liver fibrosis in determining liver cirrhosis degree with PBC, whether used alone or in combination, were analyzed by receiver operating characteristic (ROC) curve. RESULTS: LS and the four indicators of liver fibrosis within the three classes (A, B, and C) of CP scores in the observation group were higher than in the control group, with C class > B class > A class; the differences were statistically significant (P < 0.01). Although AUC values of LS within the three classes of CP scores were higher than in the four indicators of liver fibrosis, sensitivity and specificity were unstable. The ROC curves of LS combined with the four indicators of liver fibrosis revealed that: AUC and sensitivity in all indicators combined in the A class of CP score were higher than in LS alone, albeit with slightly decreased specificity; AUC and specificity in all indicators combined in the B class of CP score were higher than in LS alone, with unchanged sensitivity; AUC values (0.967), sensitivity (97.4%), and specificity (90%) of all indicators combined in the C class of CP score were higher than in LS alone (0.936, 92.1%, 83.3%). CONCLUSION: The diagnostic value of PBC cirrhosis degree in liver cirrhosis degree assessment by ARFI combined with the four indicators of serum liver fibrosis is of satisfactory effectiveness and has important clinical application value.

Characterization of focal liver masses using acoustic radiation force impulse elastography

AIM:To investigate the diagnostic performance of acoustic radiation force impulse(ARFI) elastography for characterizing focal liver mass by quantifying their stiffness.METHODS:This prospective study included 62 patients with a focal liver mass that was well visualized on conventional ultrasonography performed in our institution from February 2011 to November 2011.Among them,12 patients were excluded for ARFI measurement failure due to a lesion that was smaller than the region of the interest and at an inaccessible location(deeper than 8 cm)(n = 7) or poor compliance to hold their breath as required(n = 5).Finally,50 patients with valid ARFI measurements were enrolled.If a patient had multiple liver masses,only one mass of interest was chosen.The masses were diagnosed by histological examination or clinical diagnostic criteria.During ultrasonographic evaluation,stiffness,expressed as velocity,was checked 10 times per focal liver mass and the surrounding liver parenchyma.RESULTS:After further excluding three masses that were non-diagnostic on biopsy,a total of 47 focal mass lesions were tested,including 39(83.0%) malignant masses [24 hepatocellular carcinomas(HCC),seven cholangiocellular carcinomas(CCC),and eight liver metastases] and eight(17.0%) benign masses(five hemangiomas and three focal nodular hyperplasias,FNH).Thirty-seven(74.0%) masses were confirmed by histological examination.The mean velocity was 2.48 m/s in HCCs,1.65 m/s in CCCs,2.35 m/s in metastases,1.83 m/s in hemangiomas,and 0.97 m/s in FNHs.Although considerable overlap was still noted between malignant and benign masses,significant differences in ARFI values were observed between malignant and benign masses(mean 2.31 m/s vs 1.51 m/s,P = 0.047),as well as between HCCs and benign masses(mean 2.48 m/s vs 1.51 m/s,P = 0.006).The areas under the receiver operating characteristics curves(AUROC) for discriminating the malignant masses from benign masses was 0.724(95%CI,0.566-0.883,P = 0.048),and the AUROC for discriminating HCCs from benign masses was 0.813(95%CI,0.649-0.976,P = 0.008).To maximize the sum of sensitivity and specificity,an ARFI value of 1.82 m/s was selected as the cutoff value to differentiate malignant from benign liver masses.Furthermore,the cutoff value for distinguishing HCCs from benign masses was also determined to be 1.82 m/s.The diagnostic performance of the sum of the ARFI values for focal liver masses and the surrounding liver parenchyma to differentiate liver masses improved(AUROC = 0.853;95%CI,0.745-0.960;P = 0.002 in malignant liver masses vs benign ones and AUROC = 0.948;95%CI,0.896-0.992,P < 0.001 in HCCs vs benign masses).CONCLUSION:ARFI elastography provides additional information for the differential diagnosis of liver masses.However,our results should be interpreted in clinical context,because considerable overlap in ARFI values existed among liver masses.

Acoustic radiation force impulse of the liver

Acoustic radiation force impulse(ARFI)imaging is a new and promising ultrasound-based diagnostic technique that,evaluating the wave propagation speed,allows the assessment of the tissue stiffness.ARFI is implemented in the ultrasound scanner.By short-duration acoustic radiation forces(less than 1 ms),localized displacements are generated in a selected region of interest not requiring any external compression so reducing the operator dependency.The generated wave scan provides qualitative or quantitative(wave velocity values)responses.Several non-invasive methods for assessing the staging of fibrosis are used,in order to avoid liver biopsy.Liver function tests and transient elastography are non-invasive,sensitive and accurate tools for the assessment of liver fibrosis and for the discrimination between cirrhotic and non-cirrhotic liver.Many published studies analyse ARFI performance and feasibility in studying diffuse liver diseases and compare them to other diagnostic imaging modalities such as conventional ultrasonography and transient elastography.Solid focal liver lesions,both benign and malignant,are common findings during abdominal examinations.The accurate characterization and differential diagnosis are important aims of all the imaging modalities available today.Only few papers describe the application of ARFI technology in the study of solid focal liver lesions,with different results.In the present study,the existing literature,to the best of our knowledge,about ARFI application on diffuse and focal liver pathology has been evaluated and results and statistical analyses have been compared,bringing to the conclusion that ARFI can be used in the study of the liver with similar accuracy as transient elastography in diagnosing significant fibrosis or cirrhosis and has got some advantages in respect to transient elastography since it does not require separate equipment,better displays anatomical structures and measurements can be successfully carried out almost in every patient.

Factors correlating with acoustic radiation force impulse elastography in chronic hepatitis C

AIM: To investigate the factors other than fibrosis stage correlating with acoustic radiation force impulse (ARFI) elastograpy in chronic hepatitis C.

Parameters affecting different acoustic radiation force impulse applications in the diagnosis of fibrotic liver changes

AIM: To analyze the virtual touch tissue quantification(VTTQ) and virtual touch imaging quantification(VTIQ) techniques, and identify possible factors that may influence VTTQ and VTIQ measurements.METHODS: One hundred and eighty-six(104 women/82 men) of 323 subjects met the inclusion criteria(age > 18 years, no history of chronic or gastrointestinal disease, body-mass index(BMI) < 30 kg/m2, a fasting period of at least three hours, no history of hepatotoxic pharmaceuticals, alcohol consumption < 24 g/d in men and < 12 g/d in women, and normal findings upon ultrasound examination of the abdomen). Measurements were taken at depths of 50 mm with VTTQ, 15 mm and 25 mm with VTIQ in the right hepatic lobe, and at 15 mm with only VTIQ in the left hepatic lobe. The examiner acquired six measurements per position, thereby giving 24 measurements in total.RESULTS: The 95% confidence intervals of mean were1.23-1.29 m/s for VTTQ and 1.29-1.37 m/s, 1.17-1.23 m/s, and 1.48-1.57 m/s for VTIQ in a depth of 15 mm and 25 mm in the right hepatic lobe and 15 mm in the left hepatic lobe. Only superficial measurements in the right hepatic lobe with the VTIQ method exhibited an effect of age on shear wave velocity. Measurements acquired using the 6C1 probe with the VTTQ method showed no dependence on BMI. By comparison, BMI influenced measurements taken with the VTIQ method using the 9L4 probe in the superficial and deep areas of the right hepatic lobe, as well as in the left hepatic lobe(P = 0.0160, P = 0.0019, P = 0.0173, respectively). Gender influenced measurements at depths of 50 mm with VTTQ and 25 mm with VTIQ in the right hepatic lobe(P = 0.0001, P = 0.0269). Significant differences were found between measurements with the 6C1(VTTQ) and 9L4 probes(VTIQ)(P = 0.0067), between superficial and deep measurements(P < 0.0001), and between the right and left lobes of the liver(P < 0.0001). CONCLUSION: Measurements in the right lobe and deep regions are preferable. Gender differences must be considered. BMI must be considered when assessing VTIQ technology.

Combined acoustic radiation force impulse, aminotransferase to platelet ratio index and Forns index assessment for hepatic fibrosis grading in hepatitis B

AIM: To investigate the combined diagnostic accuracy of acoustic radiation force impulse(ARFI), aspartate aminotransferase to platelet ratio index(APRI) and Forns index for a non-invasive assessment of liver fibrosis in patients with chronic hepatitis B(CHB). METHODS: In this prospective study, 206 patients had CHB with liver fibrosis stages F0-F4 classified by METAVIR and 40 were healthy volunteers were measured by ARFI, APRI and Forns index separately or combined as indicated. RESULTS: ARFI, APRI or Forns index demonstrated a significant correlation with the histological stage(all P < 0.001). According to the AUROC of ARFI and APRI for evaluating fibrotic stages more than F2, ARFI showed an enhanced diagnostic accuracy than APRI(P < 0.05). The combined measurement of ARFI and APRI exhibited better accuracy than ARFI alone when evaluating ≥ F2 fibrotic stage(Z = 2.77, P = 0.006). Combination of ARFI, APRI and Forns index did not obviously improve the diagnostic accuracy compared to the combination of ARFI and APRI(Z = 0.958, P = 0.338). CONCLUSION: ARFI + APRI showed enhanced diagnostic accuracy than ARFI or APRI alone for significant liver fibrosis and ARFI + APRI + Forns index shows the same effect with ARFI + APRI.

Value of acoustic radiation force impulse elastography for the assessment of ascites syndrome

AIM:To assess the feasibility of performing acoustic radiation force impulse(ARFI) elastography in patients with ascites and its predictive value for the cirrhotic or non-cirrhotic etiology of ascites.METHODS:Our study included 153 patients with ascites,mean age 58.8 ± 13.1 years.One hundred and fifteen(75.2%) patients had ascites in the context of cirrhosis,29(18.9%) had non-cirrhotic ascites(diagnosed by clinical,ultrasound,endoscopic and/or laparoscopic criteria) and in 9(5.9%) cases we could not establish the etiology of ascites.We performed 10 ARFI measurements and the median value was calculated and expressed in meters/second(m/s).Among the 29 patients with non-cirrhotic ascites were included:20 laparoscopically demonstrated peritoneal carcinomatosis with histological confirmation,7 acute pancreatitis with ascites which later resolved,and one case each of lymphatic ascites and ascites in the context of a liver abscess.In 11 of the 20 patients with peritoneal carcinomatosis,the liver structure was homogenous in the ultrasound examination and in 9 patients the ultrasound exam revealed liver metastases.RESULTS:We could not obtain valid ARFI measurements in 5 patients(3.2%).The mean liver stiffness measurements by means of ARFI were statistically significantly higher in patients with cirrhotic ascites than in those with non-cirrhotic ascites:3.04 ± 0.70 vs 1.45 ± 0.59 m/s(P < 0.001).For a cut-off value of 1.8 m/s for predicting cirrhosis(and ascites in the context of cirrhosis),as obtained in a previous study,ARFI had 98.1% sensitivity,86.2% specificity,96.4% positive predictive value,92.5% negative predictive value and 95.6% accuracy for predicting cirrhotic ascites.For a cut-off value of 1.9 m/s the accuracy was 94.9% and for a 2 m/s cut-off value it was 92.8%.CONCLUSION:ARFI elastography is feasible in most patients with ascites and has a very good predictive value for the cirrhotic or non-cirrhotic etiology of ascites.

A Modified Monte Carlo Model of Speckle Tracking of Shear Wave Induced by Acoustic Radiation Force for Acousto-Optic Elasticity Imaging

A modified Monte Carlo model of speckle tracking of shear wave propagation in scattering media is proposed. The established Monte Carlo model mainly concerns the variations of optical electric field and speckle. The two- dimensional intensity distribution and the time evolution of speckles in different probe locations are obtained. The fluctuation of speckle intensity tracks the acoustic-radiation-force shear wave propagation, and especially the reduction of speckle intensity implies attenuation of shear wave. Then, the shear wave velocity is estimated quantitatively on the basis of the time-to-peak algorithm and linear regression processing. The results reveal that a smaller sampling interval yields higher estimation precision and the shear wave velocity is estimated more efficiently by using speckle intensity difference than by using speckle contrast difference according to the estimation error. Hence, the shear wave velocity is estimated to be 2.25 m/s with relatively high accuracy for the estimation error reaches the minimum （0.071）.

Normal values of shear wave velocity in liver tissue of healthy children measured using the latest acoustic radiation force impulse technology

BACKGROUND Several studies have demonstrated the feasibility and effectiveness of using ultrasound elastography to assess liver tissue stiffness.Virtual touch imaging quantification(VTIQ)based on acoustic radiation force impulse imaging has been developed as a latest and noninvasive method for assessing liver stiffness in children.AIM To determine the standard value in healthy children,and to identify possible factors that might influence the VTIQ measurement.METHODS With the ethical approval,202 children between 1 month and 15 years old were included in this study.None of them had any liver or systematic diseases.All children had a normal ultrasound scan and normal body mass index(BMI)range.The subjects were divided into four age and BMI groups.The effects of gender,age,liver lobe,measurement depth,and BMI on liver elasticity were investigated.RESULTS A significant correlation was found between age and shear wave velocity(SWV)value.At measurement depths of 1.5 cm and 2.0 cm in the left lobe,there were significant differences among the age groups.SWV values were significantly negatively correlated with the measurement depth.Gender,liver lobe,and BMI showed no significant effect on the SWV values.Age and BMI may influence the quality of the elastogram.CONCLUSION VTIQ is a noninvasive technique that is feasible to measure liver stiffness in children.The afore-mentioned velocity value obtained utilizing VTIQ method could be used as reference value for normal liver stiffness in children.

Non-invasive evaluation of liver fibrosis by acousticradiation force impulse and aminotransferase:platelet ratioindex in chronic hepatitis C

In a previous issue of the World Journal of Gastroen-terology, we have read the article by Li et al with great interest. We would like to thank the authors for their comprehensive contribution. However, it is our wish to make minor criticism over the present study from the perspective of methodology.

Comparison of Rehabilitation Outcomes with Acoustic Radiation Force (ARFI) Elastosonography in Hemiplegic Patients Treated with Neuromuscular Electrical Stimulation

To evaluate the gastrocnemius/soleus and biceps brachii muscle stiffness by Acoustic Radiation Force Impulse (ARFI) elastography in the hemiplegia patients, sixty patients with hemiplegia after stroke were recruited. Baseline data were collected including age, gender, body mass index, education level, dominant side, affected side, time since stroke, stroke etiology. All patients were evaluated with before treatment and posttreatment with Broonstroom staging, Modified Ashworth spasticity scale, and Functional Independence Measures scale. The patient was divided into 3 groups: 1) Neuromuscular electrical stimulation group, 2) Rehabilitation group, 3) Neurumusculer electrical stimulation + Rehabilitation group. Affected and unaffected side biceps and gastrocnemius, ARFI elastography measurements were used to measure thickness and elastic values. In addition, before and after treatment, length and thickness were measured from all patients. Of the 60 subjects, 28 were female (46.7%) and 32 (53.3%) were males, with an average age of 58.42 ± 9.03 years. There was a significant difference between the upper and lower limbs after the treatment in terms of Brunstroom staging. In terms of Modified Ashworth scale, there was a significant difference in lower extremity only after treatment. When compared to the affected/unaffected side, before and after treatment, there was a significant difference in the measurements in both the medial gastrocnemius and the lateral gastrocnemius in all three groups. Further research with larger numbers of patients for longer periods is needed to clarify the relationship between the muscle hardness and degree of spasticity.

Post-hepatoportoenterostomy Acoustic Radiation Force Impulse Elastography to Predict Two-year Outcome of Biliary Atresia

Background and Aims: Early identification of prognostic factors to predict transplant/death outcome of biliary atresia (BA) is challenging. We aimed to investigate the longitudinal changes and predictive value of dynamic changes in acoustic radiation force impulse elastography with shear wave speed (SWS) quantification and other parameters within three months after hepatoportoenterostomy (HPE) for 2-year BA outcomes. Methods: Seventy-four patients who underwent HPE between July 2016 and June 2019 were prospectively enrolled. Outcomes were classified into native liver survival and transplant/death groups. Acoustic radiation force im-pulse elastography was performed sequentially at 3 months intervals post-HPE. Cox regression analysis was used to de-termine the superior SWS values and other predictors of liver transplantation or death. Results: Among patients 2 years of age, 36 survived with a native liver, nine died, and 29 underwent liver transplantation. The trend in SWS levels in the transplant/death group was significantly different from that in the native liver survival group. ΔSWS at 1-3 months post-HPE and total bilirubin at 1 month post-HPE were se-lected as superior predictors of liver transplantation or death using multivariate Cox regression models: hazard ratio (HR)=1.927;95% confidence interval (CI): 1.475-2.661;p<0.001 and HR=1.010;95% CI: 1.003-1.017;p=0.007, respectively. The combination of the selected ΔSWS and total bilirubin had good predictive power, with an area under the receiver operating characteristics curve of 0.89, specificity 94.44% and sensitivity 73.68%. Conclusions: Our results suggest that early postoperative bilirubin levels and SWS changes were reliable predictors of 2-year BA outcomes.

ARFI-VTQ技术定量评价下肢肌间静脉单纯扩张与急性期血栓的探讨

目的 探讨ARFI-VTQ技术对下肢肌间静脉单纯扩张与急性期血栓的定量分析能力。方法 选取单纯下肢肌间静脉扩张患者29例(30肢)作为肌间静脉扩张组,单纯下肢肌间静脉急性期血栓患者29例(41肢)作为急性期血栓组,分析两组二维及多普勒声像图特征,并分别行ARFI-VTQ检查,获得两组患者各自SWV测值,比较两组患者测值差异性;绘制受试者工作特征曲线(ROC),获得区分下肢肌间静脉单纯扩张与急性期血栓的最佳结果。结果 肌间静脉扩张组超声检查表现:管腔内呈无回声,部分自发显影,呈流沙样改变;管腔可被压闭,挤压后可见血流信号显示;SWV测值0.84~1.59 m/s,平均(1.32±0.17)m/s,取样深度2.0~3.5 cm,平均(2.64±0.41)cm。急性期血栓组超声检查表现:管腔内呈极低回声或低回声;管腔不可压闭,无血流信号或少许血流信号;SWV测值1.54~2.41 m/s,平均(1.86±0.19)m/s,取样深度0.9~3.6 cm,平均(2.43±0.59)cm。绘制ROC曲线,ROC曲线下面积(AUC)99.5%(95%CI:0.985-1.000,P<0.001),以1.60 m/s为截断值,ARFI-VTQ技术诊断急性期血栓的灵敏度为95.0%,特异度为100%。结论 ARFI-VTQ技术能够定量分析单纯肌间静脉扩张与急性期肌间静脉血栓,在两者的鉴别诊断方面具有良好的敏感度及特异度。

Noninvasive diagnosis of cirrhosis:A review of different imaging modalities

Progressive hepatic fibrosis can lead to cirrhosis,so its early detection is fundamental.Staging fibrosis is also critical for prognosis and management.The gold standard for these aims is liver biopsy,but it has several drawbacks,as it is invasive,expensive,has poor acceptance,is prone to inter observer variability and sampling errors,has poor repeatability,and has a risk of complications and mortality.Therefore,non-invasive imaging tests have been developed.This review mainly focuses on the role of transient elastography,acoustic radiation force impulse imaging,and magnetic resonance-based methods for the noninvasive diagnosis of cirrhosis.