Factors associated with unreliable liver stiffness measurement and its failure with transient elastography in the Chinese population

Larger biopsies evaluation of transient elastography for detecting advanced fibrosis in patients with compensated chronic hepatitis B

BACKGROUND AND AIM

Although larger biopsies sample had been recommended for the study of non-invasive liver fibrosis assessment, few studies with larger biopsies for transient elastography (TE) detecting liver fibrosis had been reported. The present study tries to re-evaluate the performance of TE for detecting advanced fibrosis (≥F3) with larger biopsies in patients with compensated chronic hepatitis B.

METHODS

A total of 375 compensated patients were analyzed, who had undergone liver biopsy, reliable TE and routine blood tests.

RESULTS

The area under the receiver operating characteristic curve (AUC) was influenced by liver biopsy sample: 0.873 (95% confidence interval 0.838-0.909) in total patients, 0.880 (0.844-0.917) in length ≥ 15 mm, 0.897 (0.863-0.932) in length ≥ 20 mm and 0.911 (0.874-0.949) in length ≥ 25 mm. In patients with sample length ≥ 20 mm, the cutoffs to exclude and confirm advanced fibrosis were 7.1 kPa and 12.7 kPa, respectively. Stratified by alanine aminotransferase of two times the upper limit of normal (ALT 2 × ULN), transient elastography detecting advanced fibrosis with the most efficiency by 72.5% of patients obviated from liver biopsy. In patients with normal bilirubin and ALT < 2 × ULN, the area was 0.921 (0.860-0.982), and cutoffs for excluding and confirming diagnosis were 7.4 kPa and 10.6 kPa, respectively; 80% of patients could be classified with or without advanced fibrosis (AF). In patients with normal bilirubin and ALT ≥ 2 × ULN, the corresponding numbers were 0.885 (0.824-0.947), 7.5 kPa, 12.7 kPa and 79.2%, respectively.

CONCLUSIONS

Inadequate sample study would underestimate the efficiency of TE on detecting advanced fibrosis. With ALT 2 × ULN stratified cutoffs, TE determined nearly 80% of patients with normal bilirubin as AF or non-AF and obviated them from liver biopsies.

Diagnosis of liver fibrosis and cirrhosis using liver stiffness measurement: comparison between M and XL probe of FibroScan®

BACKGROUND & AIMS

Unreliable results of liver stiffness measurement are obtained in 16% of cases and are independently associated with body mass index (BMI) greater than 30 kg/m(2). A new FibroScan® probe (XL probe) was designed specifically for obese patients. The aim of this study was to evaluate the accuracy of liver stiffness measurement using M and XL probes of Fibroscan® for the diagnosis of fibrosis and cirrhosis in a large cohort of patients.

METHODS

Consecutive patients undergoing liver biopsies for chronic liver disease were prospectively recruited. Liver stiffness measurement was performed within 1 week before liver biopsy using both M and XL probes of FibroScan®.

RESULTS

A total of 286 patients were evaluated. A reliable liver stiffness measurement using M probe was obtained in 79.7% of cases. In the other 21.3%, liver stiffness measurement using XL probe was obtained in 56.9% of patients. A strong correlation was found between M and XL values, regardless of BMI. In all groups, median liver stiffness measurement using the XL probe was significantly lower than liver stiffness measurement using the M probe. By multivariate analysis, unsuccessful liver stiffness examination with M probe was independently associated with age >50 years and BMI >30 kg/m(2). By univariate analysis, only BMI >30 kg/m(2) was associated with unsuccessful liver stiffness measurement with XL probe. No significant difference was observed between the M and XL probes for the diagnosis of liver fibrosis.

CONCLUSIONS

Liver stiffness measurement with either M or XL probe is possible in 91.2% of patients with comparable diagnostic accuracy. In clinical practice, the M probe could be used as first step for liver stiffness measurement. In case of no valid shot or unreliable measurement, the XL probe could be used. This result could be useful for the assessment of liver fibrosis in NAFLD and/or obese patients.

Discordance in fibrosis staging between liver biopsy and transient elastography using the FibroScan XL probe

BACKGROUND & AIMS

The FibroScan XL probe facilitates liver stiffness measurement (LSM) by transient elastography (TE) in obese patients, yet factors affecting its accuracy have not been described. Our objectives were to examine the prevalence, risk factors, and causes of discordance between fibrosis estimated by the FibroScan XL probe and biopsy.

METHODS

Two hundred and ten patients with chronic liver disease (45% viral hepatitis, 55% nonalcoholic fatty liver disease (NAFLD) and a body mass index (BMI) ≥ 28 kg/m(2)) underwent liver biopsy and TE with the FibroScan XL probe. Predictors of discordance ≥ 2 fibrosis stages between measures, which occurred in 11% of patients (n=24), were identified by comparing patient, TE, and biopsy characteristics of discordant and non-discordant cases.

RESULTS

Fibrosis estimated by the FibroScan XL probe was greater than biopsy in 75% (18/24) of discordant cases. Although biopsy quality was not associated with discordance, discordant cases were less likely to have ≥ 10 valid shots (75% vs. 97%; p=0.001), a success rate ≥ 60% (67% vs. 95%; p <0.0005), and an interquartile range over median liver stiffness (IQR/M) <21% (37% vs. 57%; p=0.07) than non-discordant cases. However, only increased BMI (odds ratio [OR] 1.09 per kg/m(2); 95% confidence interval [CI] 1.01-1.18; p=0.04) was independently associated with discordance; liver stiffness was of borderline significance (OR 1.73 per log(10)-transformed value; 95% CI 0.95-3.18; p=0.08). Discordance was 4- to 5-fold more frequent among patients with severe obesity (BMI ≥ 40 kg/m(2): 32% vs. 8%) and liver stiffness above the median of 7.0 kPa (20% vs. 4%; both p <0.0005).

CONCLUSIONS

Discordance between liver fibrosis estimated by biopsy and TE using the FibroScan XL probe was infrequent in this obese population. Patients with severe obesity and elevated liver stiffness have the greatest risk of discordance.

Feasibility study and control values of transient elastography in healthy children

Transient elastography (TE) is a new technique for the non-invasive assessment of liver fibrosis. The degree of fibrosis is equivalent to the liver stiffness measured in kilopascal (kPa). It is frequently used in adult patients with a mean normal stiffness of 4.4-5.5 kPa. Since 2008, liver stiffness can be measured even in small children and infants following the availability of a new probe with a smaller diameter (S-probe 5 mm) than the regular probe (M-probe 7 mm). We report control values for healthy children between 0 and 18 years and investigated the feasibility of this technique in a pediatric population. For control values, TE was performed in infants and children after exclusion of liver disease by medical history, clinical examination, blood investigation, and abdominal ultrasound. For feasibility analyses the results of all TE performed in our clinic were analyzed irrespective of the underlying disease. Liver stiffness was measured with the S-probe (thorax diameter <45 cm (S1) or 45-75 cm (S2)) and the M-probe (thorax diameter >75 cm) according to the manufacturer's recommendations. A total of 240 healthy children were analyzed to establish control values. The median liver stiffness was 4.7 kPa resulting in an upper limit of normal of 6.47 kPa. Median values of stiffness were significantly age dependent with 4.40, 4.73, and 5.1 kPa in children 0-5, 6-11, and 12-18 years (p = 0.001) while the interquartile range decreased with age (0.8, 0.7, and 0.6 kPa). The resulting upper limit of normal (median plus 1.64 times standard deviation) was 5.96, 6.65, and 6.82 kPa. Girls between 11 and 18 years showed a significantly lower median stiffness than boys of the same age (4.7 vs. 5.6 kPa; p < 0.005). Feasibility was tested in 975 consecutive liver stiffness measurements (LSM) in children 0-18 years of age. Patients with invalid LSM were significantly younger than those with valid LSM (5.8 vs. 9.7 years, p < 0.0001), showed a significantly higher stiffness (10.2 vs. 6.17, p < 0.0001), and examinations took significantly longer (202 vs. 160 s, p < 0.0001). TE is technically possible in children of all age groups. The upper limit of normal increases significantly with age. Due to movement artifacts the measurement is reliable from the age of 6 without sedation. In younger children the number of invalid measurements increases significantly. Further studies are needed to asses the value of TE in the diagnosis and follow-up of liver disease in pediatric hepatology.

Feasibility and diagnostic performance of the FibroScan XL probe for liver stiffness measurement in overweight and obese patients

Failure of liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) and unreliable results occur in ≈ 5% and 15% of patients, respectively, mainly due to obesity. In this multicenter study, we evaluated the feasibility and performance of the novel FibroScan XL probe in 276 patients with chronic liver disease (42% viral hepatitis, 46% nonalcoholic fatty liver disease [NAFLD]) and a body mass index (BMI) ≥ 28 kg/m(2) . Patients underwent liver biopsy and TE with the standard M and XL probes. TE failure was defined as no valid LSMs and unreliable examinations as <10 valid LSMs or an interquartile range (IQR)/LSM >30% or success rate <60%. Probe performance for diagnosing ≥ F2 fibrosis and cirrhosis (F4) versus biopsy were examined using areas under receiver operating characteristic curves (AUROC). FibroScan failure was less frequent with the XL probe than the M probe (1.1% versus 16%) and the XL probe was more often reliable (73% versus 50%; both P < 0.00005). Reliable results with the XL probe were obtained in 61% of patients in whom the M probe was unreliable. Among 178 patients with ≥ 10 valid LSMs using both probes, liver stiffness was highly correlated between probes (ρ = 0.86; P < 0.0005); however, median liver stiffness was lower using the XL probe (6.8 versus 7.8 kPa; P < 0.00005). The AUROC of the XL and M probes were similar for ≥ F2 fibrosis (0.83 versus 0.86; P = 0.19) and cirrhosis (0.94 versus 0.91; P = 0.28).

CONCLUSION

Compared with the M probe, the FibroScan XL probe reduces TE failure and facilitates reliable LSM in obese patients. Although the probes have comparable accuracy, lower liver stiffness cutoffs will be necessary when the XL probe is used to noninvasively assess liver fibrosis.

Feasibility study and control values of transient elastography in healthy children

Transient elastography (TE) is a new technique for the non-invasive assessment of liver fibrosis. The degree of fibrosis is equivalent to the liver stiffness measured in kilopascal (kPa). It is frequently used in adult patients with a mean normal stiffness of 4.4-5.5 kPa. Since 2008, liver stiffness can be measured even in small children and infants following the availability of a new probe with a smaller diameter (S-probe 5 mm) than the regular probe (M-probe 7 mm). We report control values for healthy children between 0 and 18 years and investigated the feasibility of this technique in a pediatric population. For control values, TE was performed in infants and children after exclusion of liver disease by medical history, clinical examination, blood investigation, and abdominal ultrasound. For feasibility analyses the results of all TE performed in our clinic were analyzed irrespective of the underlying disease. Liver stiffness was measured with the S-probe (thorax diameter <45 cm (S1) or 45-75 cm (S2)) and the M-probe (thorax diameter >75 cm) according to the manufacturer's recommendations. A total of 240 healthy children were analyzed to establish control values. The median liver stiffness was 4.7 kPa resulting in an upper limit of normal of 6.47 kPa. Median values of stiffness were significantly age dependent with 4.40, 4.73, and 5.1 kPa in children 0-5, 6-11, and 12-18 years (p = 0.001) while the interquartile range decreased with age (0.8, 0.7, and 0.6 kPa). The resulting upper limit of normal (median plus 1.64 times standard deviation) was 5.96, 6.65, and 6.82 kPa. Girls between 11 and 18 years showed a significantly lower median stiffness than boys of the same age (4.7 vs. 5.6 kPa; p < 0.005). Feasibility was tested in 975 consecutive liver stiffness measurements (LSM) in children 0-18 years of age. Patients with invalid LSM were significantly younger than those with valid LSM (5.8 vs. 9.7 years, p < 0.0001), showed a significantly higher stiffness (10.2 vs. 6.17, p < 0.0001), and examinations took significantly longer (202 vs. 160 s, p < 0.0001). TE is technically possible in children of all age groups. The upper limit of normal increases significantly with age. Due to movement artifacts the measurement is reliable from the age of 6 without sedation. In younger children the number of invalid measurements increases significantly. Further studies are needed to asses the value of TE in the diagnosis and follow-up of liver disease in pediatric hepatology.