Performance and cutoffs for liver fibrosis staging of a two-dimensional shear wave elastography technique.

OBJECTIVES: To assess performance and cutoffs of the 2-dimensional shear wave elastography technique available on the Aplio i800 ultrasound system (Canon Medical Systems, Japan), using transient elastography as reference standard, and to assess the correlation of shear-wave-speed dispersion with liver fibrosis or steatosis. METHODS: This was a single-center cross-sectional study. The correlations between values obtained with transient elastography and 2-dimensional-shear wave elastography, and between shear-wave-speed dispersion and fibrosis or steatosis, were assessed with Pearson's r. The diagnostic performance of the 2-dimensional-shear wave elastography for staging significant fibrosis and severe fibrosis compared to transient elastography was assessed using the area under the receiver operating characteristic curve analysis. RESULTS: Three hundred sixty-seven patients (198 males and 169 females) were studied. There was a high correlation between 2-dimensional-shear wave elastography and transient elastography (r = 0.87, P < 0.0001). The area under the receiver operating characteristics of 2-dimensional-shear wave elastography for staging significant fibrosis (F2) and severe fibrosis (F3-F4), respectively, were 0.97 (95% confidence interval, 0.91-0.98) and 0.97 (95% confidence interval, 0.95-0.99). The best cutoffs for significant fibrosis and severe fibrosis, respectively, were > 7 and > 9 kPa. Shear-wave-speed dispersion showed a high correlation with fibrosis (r = 0.85, P < 0.0001), whereas there was a very weak correlation with steatosis. CONCLUSIONS: The results of this study show that this 2-dimensional-shear wave elastography technique is accurate for staging liver fibrosis. Shear-wave-speed dispersion is highly correlated with liver fibrosis but not with steatosis.

The clinical value of controlled attenuation parameter for the noninvasive assessment of liver steatosis.

BACKGROUND & AIMS: Ultrasound is the imaging modality most widely utilized in the general population for diagnostic purposes. Controlled attenuation parameter is a novel noninvasive method for assessing steatosis. Our aim was to investigate whether the clinical value of controlled attenuation parameter in patients referred for abdominal ultrasound examinations is affected by liver fibrosis. METHODS: Consecutive patients referred for abdominal ultrasound examinations were enrolled. Controlled attenuation parameter and liver stiffness were assessed with the FibroScan (Echosens, France). Liver fibrosis was staged according to published cutoffs of liver stiffness measurements. Pearson's or Spearman's rank correlation coefficient was used to test the association between two study variables. Optimal cutoff of controlled attenuation parameter for diagnosing liver steatosis (S≥2) was 256 dB/m. The diagnostic performance and accuracy of dichotomized controlled attenuation parameter, ultrasound and body mass index were analysed using the imperfect gold standard methodology. RESULTS: A total of 726 subjects (464 males and 262 females) were studied. Five hundred and eight-nine (81.1%) patients were affected by chronic viral hepatitis. Correlation of controlled attenuation parameter with ultrasound score was 0.48 and 0.57 in patients with and without chronic viral hepatitis respectively. In patients with chronic viral hepatitis, ultrasound, dichotomized controlled attenuation parameter and body mass index showed performance of 58.2%, 82.3% and 46.7%, respectively, whereas in patients without chronic viral hepatitis, the performance was 86.4%, 68.6% and 48.6% respectively. CONCLUSIONS: In patients with chronic viral hepatitis and advanced liver fibrosis, controlled attenuation parameter performs better than ultrasound for assessing liver steatosis, whereas in patients without viral hepatitis and with nonsignificant liver disease ultrasound shows the best performance.

Performance of liver stiffness measurements by transient elastography in chronic hepatitis.

AIM: To compare results of liver stiffness measurements by transient elastography (TE) obtained in our patients population with that used in a recently published meta-analysis. METHODS: This was a single center cross-sectional study. Consecutive patients with chronic viral hepatitis scheduled for liver biopsy at the outpatient ward of our Infectious Diseases Department were enrolled. TE was carried out by using FibroScan™ (Echosens, Paris, France). Liver biopsy was performed on the same day as TE, as day case procedure. Fibrosis was staged according to the Metavir scoring system. The diagnostic performance of TE was assessed by using receiver operating characteristic (ROC) curves and the area under the ROC curve analysis. RESULTS: Two hundred and fifty-two patients met the inclusion criteria. Six (2%) patients were excluded due to unreliable TE measurements. Thus, 246 (171 men and 75 women) patients were analyzed. One hundred and ninety-five (79.3%) patients had chronic hepatitis C, 41 (16.7%) had chronic hepatitis B, and 10 (4.0%) were coinfected with human immunodeficiency virus. ROC curve analysis identified optimal cut-off value of TE as high as 6.9 kPa for F ≥ 2; 7.9 kPa for F ≥ 3; 9.6 kPa for F = 4 in all patients (n = 246), and as high as 6.9 kPa for F ≥ 2; 7.3 kPa for F ≥ 3; 9.3 kPa for F = 4 in patients with hepatitis C (n = 195). Cut-off values of TE obtained by maximizing only the specificity were as high as 6.9 kPa for F ≥ 2; 9.6 kPa for F ≥ 3; 12.2 kPa for F = 4 in all patients (n = 246), and as high as 7.0 kPa for F ≥ 2; 9.3 kPa for F ≥ 3; 12.3 kPa for F = 4 in patients with hepatitis C (n = 195). CONCLUSION: The cut-off values of TE obtained in this single center study are comparable to that obtained in a recently published meta-analysis that included up to 40 studies.

Reproducibility of real-time shear wave elastography in the evaluation of liver elasticity.

OBJECTIVE: To evaluate the reproducibility of real-time shear wave elastography in assessing liver elasticity in healthy volunteers. METHODS: Forty-two volunteers were studied in day 1. Shear wave elastography studies were performed by using the ultrasound system Aixplorer™ (SuperSonic Imagine S.A., Aix-en-Provence, France) with a convex broadband probe. Measurements were carried by two operators, an expert (operator 1) and a novice (operator 2). Examinations were performed on the right lobe of the liver. Each operator performed 10 consecutive measurements in each volunteer. In a subset of volunteers (n=18) measurements were performed twice on two different days (day 1 and day 2). Intraobserver and interobserver agreement were assessed by intraclass correlation coefficient. RESULTS: Intraobserver agreement between measurements performed in the same subject in the same day (day 1 or day 2) showed intraclass correlation coefficient values of 0.95 (95% confidence interval, 0.93-0.98) and 0.93 (95% confidence interval, 0.90-0.96) for operator 1 and operator 2, respectively. Intraobserver agreement between measurements performed in the same subject in different days showed intraclass correlation coefficient values of 0.84 (95% confidence interval, 0.69-0.98) and 0.65 (95% confidence interval, 0.39-0.91) for operator 1 and operator 2, respectively. Interobserver agreement was 0.88 (95% confidence interval, 0.82-0.94). CONCLUSIONS: The results of this study show that shear wave elastography is a reliable and reproducible noninvasive method for the assessment of liver elasticity. Expert operator had higher reproducibility of measurements over time than novice operator.

Performance of real-time strain elastography, transient elastography, and aspartate-to-platelet ratio index in the assessment of fibrosis in chronic hepatitis C.

OBJECTIVE: The purpose of this article is to evaluate the diagnostic performance of transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index in assessing fibrosis in patients with chronic hepatitis C by using histologic Metavir scores as reference standard. SUBJECTS AND METHODS: Consecutive patients with chronic hepatitis C scheduled for liver biopsy were enrolled. Liver biopsy was performed on the same day as transient elastography and real-time strain elastography. Transient elastography and real-time strain elastography were performed in the same patient encounter by a single investigator using a medical device based on elastometry and an ultrasound machine, respectively. Diagnostic performance was assessed by using receiver operating characteristic curves and area under the receiver operating characteristic curve (AUC) analysis. RESULTS: One hundred thirty patients (91 men and 39 women) were analyzed. The cutoff values for transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index were 6.9 kPa, 1.82, and 0.37, respectively, for fibrosis score of 2 or higher; 7.3 kPa, 1.86, and 0.70, respectively, for fibrosis score of 3 or higher; and 9.3 kPa, 2.33, and 0.70, respectively, for fibrosis score of 4. AUC values of transient elastography, real-time strain elastography, aspartate-to-platelet ratio index were 0.88, 0.74, and 0.86, respectively, for fibrosis score of 2 or higher; 0.95, 0.80, and 0.89, respectively, for fibrosis score of 3 or higher; and 0.97, 0.80, and 0.84, respectively, for fibrosis score of 4. A combination of the three methods, when two of three were in agreement, showed AUC curves of 0.93, 0.95, and 0.95 for fibrosis scores of 2 or higher, 3 or higher, and 4, respectively. CONCLUSION: Transient elastography, real-time strain elastography, and aspartate-to-platelet ratio index values were correlated with histologic stages of fibrosis. Transient elastography offered excellent diagnostic performance in assessing severe fibrosis and cirrhosis. Real-time elastography does not yet have the potential to substitute for transient elastography in the assessment of liver fibrosis.