Acoustic radiation force impulse elastography as compared to transient elastography and liver biopsy in patients with chronic hepatopathies.

PURPOSE: To compare two methods of noninvasive assessment: transient elastography (TE) and acoustic radiation force impulse elastography (ARFI). PATIENTS AND METHODS: Our study included 114 subjects: 38 healthy volunteers, (considered to have no fibrosis - F 0) and 76 patients with chronic liver disease: 53 who had undergone liver biopsy (LB) (7 with F 1, 24 with F 2, 22 with F 3 Metavir) and 23 previously diagnosed with cirrhosis (F4 Metavir). In each patient we performed a liver stiffness measurement by means of TE and ARFI. ARFI (shear wave velocity quantification) was performed at 3 points: at 0 - 1 cm, at 1 - 2 cm and at 2 - 3 cm under the capsule. For each depth, 5 valid measurements were made, and a median value was calculated, measured in m/sec. RESULTS: A direct, strong, linear correlation (Spearman rho = 0.848) was found between TE and the stage of fibrosis (p < 0.001). A significant, direct correlation was found between ARFI measurements made 1 - 2 cm and 2 - 3 cm below the liver capsule and the severity of fibrosis (rho = 0.675 and 0.714 respectively). The subcapsularly measured ARFI values showed a poor correlation with fibrosis (rho = 0.469). The best test for predicting significant fibrosis (F ≥ 2) was TE, with the area under receiver-operating characteristic curve (AUROC) 0.908, significantly larger than the AUROCs for ARFI. If only ARFI is considered, measurements made 1 - 2 and 2 - 3 cm below the capsule have the best predictive value, with AUROCs not significantly different from each other (0.767 and 0.731, respectively). For predicting fibrosis (F > 0), TE had the best predictive value: optimized cut-off 5.65 kPa (AUROC -0.898). For ARFI, the cut-offs were: 1.4 m/sec, AUROC -0.747 (1 - 2 cm), and 1.26 m/sec AUROC -0.721 (2 - 3 cm). For predicting cirrhosis (F = 4 Metavir), the optimized cut-offs were: TE -12.9 kPa (AUROC -0.994); ARFI - 1.78 m/sec for measurements made 2 - 3 cm below the capsule, AUROC - 0.951. CONCLUSION: At present, liver elasticity evaluation by means of ARFI is not superior to TE for the assessment of liver fibrosis. For ARFI, the most reliable results are obtained if measurements are made 1 - 2 and 2 - 3 cm below the liver capsule. ARFI is an accurate test for the diagnosis of cirrhosis.

What did we learn from the first 3,459 cases of liver stiffness measurement by transient elastography (FibroScan®)?

PURPOSE: Chronic viral hepatopathies can be evaluated through invasive or noninvasive methods. The aim of this paper was to assess the indications and results of transient elastographic (TE) evaluation of the liver in patients with chronic viral hepatitis and cirrhosis. MATERIALS AND METHODS: We retrospectively assessed all the liver stiffness measurements (LSM) (FibroScan®) performed over a two-year period (2007 - 2009). RESULTS: 3,459 TE evaluations were made mainly for the assessment of: HCV hepatitis, HBV infection (chronic hepatitis and inactive HBV carriers), biviral hepatitis (B + C or B + D), cirrhosis and in 176 normal subjects (to establish the normal values of LSM). From the 3,459 FS evaluations, we could not obtain valid LSM in 183 cases (5.3 %). 93.9 % of the patients in the failure group were overweight (BMI > 25 kg/m²). In 527 cases (16 %) the SR (success rate = number of valid measurements/total number of measurements) was < 60 %. TE reproducibility was analyzed in 287 cases. The ICCs for the three operators were 0.985, 0.949, and 0.874 respectively, and the overall ICC was 0.982. 596 cases of cirrhosis were evaluated. A cut-off value of 23.3kPa was found to predict the presence of at least grade 2 esophageal varices. CONCLUSION: LSM by means of TE is a promising noninvasive evaluation method, which can be used in numerous clinical situations, some in which its value is well established (suspicion of LC, predicting significant fibrosis) and some in which its value is less known (HBV chronic hepatitis, inactive HBV carriers or severity of portal hypertension).