Feasibility and reliability of the FibroScan S2 (pediatric) probe compared with the M probe for liver stiffness measurement in small adults with chronic liver disease.

BACKGROUND: The success of liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) is influenced by anthropometric factors. In smaller adults, the M probe may fail due to narrow intercostals spaces and rib interference. We aimed to compare LSM using the FibroScan S2 (pediatric) probe with the M probe in small adults with chronic liver disease. MATERIAL AND METHODS: In this prospective study, 41 liver disease patients and 18 controls with a thoracic perimeter ≤ 75 cm underwent LSM using the FibroScan M and S2 probes. TE failure was defined as no valid LSMs and unreliable examinations as < 10 valid LSMs, an interquartile range (IQR)/LSM > 30%, or success rate < 60%. RESULTS: TE failure was not observed and reliability did not differ between the M and S2 probes (86% vs. 95%; P = 0.20). Liver stiffness measured using the M and S2 probes was highly correlated (ρ = 0.81; P < 0.0005) and median liver stiffness did not differ between probes (4.5 vs. 4.4 kPa; P = 0.10). However, in participants with a skin-capsular distance ≥ 15 mm, median liver stiffness was higher using the S2 probe (5.5 vs. 4.9 kPa; P = 0.008). When compared with validated liver stiffness cut-offs, the S2 probe would have overestimated the stage of fibrosis compared with the M probe in 10% of patients. CONCLUSIONS: The FibroScan S2 probe does not improve the feasibility of LSM in adults of smaller stature and may overestimate liver stiffness compared with the M probe. The FibroScan M probe should remain the preferred tool for LSM in small adults with chronic liver disease.

The feasibility and reliability of transient elastography using Fibroscan®: a practice audit of 2335 examinations.

BACKGROUND: Liver stiffness measurement (LSM) using transient elastography is widely used in the management of patients with chronic liver disease. OBJECTIVES: To examine the feasibility and reliability of LSM, and to identify patient and operator characteristics predictive of poorly reliable results. METHODS: The present retrospective study investigated the frequency and determinants of poorly reliable LSM (interquartile range [IQR]/median LSM [IQR/M] >30% with median liver stiffness ≥7.1 kPa) using the FibroScan (Echosens, France) over a three-year period. Two experienced operators performed all LSMs. Multiple logistic regression analyses examined potential predictors of poorly reliable LSMs including age, sex, liver disease, the operator, operator experience (<500 versus ≥500 scans), FibroScan probe (M versus XL), comorbidities and liver stiffness. In a subset of patients, medical records were reviewed to identify obesity (body mass index ≥30 kg/m2). RESULTS: Between July 2008 and June 2011, 2335 patients with liver disease underwent LSM (86% using the M probe). LSM failure (no valid measurements) occurred in 1.6% (n=37) and was more common using the XL than the M probe (3.4% versus 1.3%; P=0.01). Excluding LSM failures, poorly reliable LSMs were observed in 4.9% (n=113) of patients. Independent predictors of poorly reliable LSM included older age (OR 1.03 [95% CI 1.01 to 1.05]), chronic pulmonary disease (OR 1.58 [95% CI 1.05 to 2.37), coagulopathy (OR 2.22 [95% CI 1.31 to 3.76) and higher liver stiffness (OR per kPa 1.03 [95% CI 1.02 to 1.05]), including presumed cirrhosis (stiffness ≥12.5 kPa; OR 5.24 [95% CI 3.49 to 7.89]). Sex, diabetes, the underlying liver disease and FibroScan probe were not significant. Although reliability varied according to operator (P<0.0005), operator experience was not significant. In a subanalysis including 434 patients with body mass index data, obesity influenced the rate of poorly reliable results (OR 2.93 [95% CI 0.95 to 9.05]; P=0.06). CONCLUSIONS: FibroScan failure and poorly reliable LSM are uncommon. The most important determinants of poorly reliable results are older age, obesity, higher liver stiffness and the operator, the latter emphasizing the need for adequate training.

Liver stiffness by transient elastography predicts liver-related complications and mortality in patients with chronic liver disease.

BACKGROUND: Liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) is a validated method for noninvasively staging liver fibrosis. Most hepatic complications occur in patients with advanced fibrosis. Our objective was to determine the ability of LSM by TE to predict hepatic complications and mortality in a large cohort of patients with chronic liver disease. METHODS: In consecutive adults who underwent LSM by TE between July 2008 and June 2011, we used Cox regression to determine the independent association between liver stiffness and death or hepatic complications (decompensation, hepatocellular carcinoma, and liver transplantation). The performance of LSM to predict complications was determined using the c-statistic. RESULTS: Among 2,052 patients (median age 51 years, 65% with hepatitis B or C), 87 patients (4.2%) died or developed a hepatic complication during a median follow-up period of 15.6 months (interquartile range, 11.0-23.5 months). Patients with complications had higher median liver stiffness than those without complications (13.5 vs. 6.0 kPa; P<0.00005). The 2-year incidence rates of death or hepatic complications were 2.6%, 9%, 19%, and 34% in patients with liver stiffness <10, 10-19.9, 20-39.9, and ≥40 kPa, respectively (P<0.00005). After adjustment for potential confounders, liver stiffness by TE was an independent predictor of complications (hazard ratio [HR] 1.05 per kPa; 95% confidence interval [CI] 1.03-1.06). The c-statistic of liver-stiffness for predicting complications was 0.80 (95% CI 0.75-0.85). A liver stiffness below 20 kPa effectively excluded complications (specificity 93%, negative predictive value 97%); however, the positive predictive value of higher results was sub-optimal (20%). CONCLUSIONS: Liver stiffness by TE accurately predicts the risk of death or hepatic complications in patients with chronic liver disease. TE may facilitate the estimation of prognosis and guide management of these patients.