Accuracy of liver stiffness measurement for the diagnosis of cirrhosis in patients with chronic liver diseases

Liver fibrosis on account of chronic hepatitis C is more severe in HIV-positive than HIV-negative patients despite antiretroviral therapy

The recent availability of non-invasive tools to measure liver fibrosis has allowed examination of its extent and determination of predictors in all patients with chronic hepatitis C virus (HCV) infection. On the other hand, most information on hepatic fibrosis in HCV/human immunodeficiency virus (HIV)-coinfected patients has been derived from liver biopsies taken before highly active antiretroviral therapy (HAART) was widely available. All consecutive HCV patients with elevated aminotransferases seen during the last 3 years were evaluated and liver fibrosis measured using transient elastography (FibroScan) and biochemical indexes. Patients were split according to their HIV serostatus. A total of 656 (69.6%) HCV-monoinfected and 287 (30.4%) HIV/HCV-coinfected patients were assessed. Mean CD4 count of coinfected patients was 493 cells/muL and 88% were under HAART (mean time, 4.2 +/- 2.4 years). Advanced liver fibrosis or cirrhosis was recognized in 39% of the coinfected and 18% of the monoinfected patients (P < 0.005). A good correlation was found between FibroScan) and biochemical indexes [AST to platelet ratio index (r = 0.405, P < 0.0001), FIB-4 (r = 0.393, P < 0.0001) and Forns (r = 0.407, P < 0.0001)], regardless of the HIV status. In the multivariate analysis, age >45 years, body mass index (BMI) >25 kg/m(2), and HIV infection were independently associated with advanced liver fibrosis or cirrhosis. HIV/HCV-coinfected patients have more advanced liver fibrosis than HCV-monoinfected patients despite the immunologic benefit of HAART.

MR elastography of liver fibrosis: preliminary results comparing spin-echo and echo-planar imaging

The purpose of this study was to prospectively compare the performance of magnetic resonance (MR) elastography using echo-planar and spin-echo imaging for staging of hepatic fibrosis. Twenty-four patients who had liver biopsy for suspicion of chronic liver disease had MR elastography performed with both spin-echo and echo-planar sequences. At histology, the fibrosis stage was assessed according to METAVIR. The data acquisition time was about 20 min using spin-echo, and only 2 min using echo-planar imaging. The hepatic signal-to-noise ratios were similar on both images (22.51 +/- 5.37 for spin-echo versus 21.02 +/- 4.76 for echo-planar, p = 0.33). The elasticity measurements and the fibrosis stages were strongly correlated. The Spearman correlation coefficients were r = 0.91 (p < 0.01) with spin-echo and r = 0.84 (p < 0.01) with echo-planar sequences. These correlation coefficients did not differ significantly (p = 0.17). A strong correlation was also observed between spin-echo and echo-planar elasticity (r = 0.83, p < 0.001), without systematic bias. The results of our study showed that echo-planar imaging substantially decreased the data acquisition time of MR elastography, while maintaining the image quality and diagnostic performance for staging of liver fibrosis. This suggests that echo-planar MR elastography could replace spin-echo MR elastography in clinical practice.

Non-invasive evaluation of liver fibrosis using transient elastography

Transient elastography (TE, FibroScan) is a novel non-invasive method that has been proposed for the assessment of hepatic fibrosis in patients with chronic liver diseases, by measuring liver stiffness. TE is a rapid and user-friendly technique that can be easily performed at the bedside or in the outpatient clinic with immediate results and good reproducibility. Limitations include failure in around 5% of cases, mainly in obese patients. So far, TE has been mostly validated in chronic hepatitis C, with diagnostic performance equivalent to that of serum markers for the diagnosis of significant fibrosis. Combining TE with serum markers increases diagnostic accuracy and as a result, liver biopsy could be avoided for initial assessment in most patients with chronic hepatitis C. This strategy warrants further evaluation in other aetiological types of chronic liver diseases. TE appears to be an excellent tool for early detection of cirrhosis and may have prognostic value in this setting. As TE has excellent patient acceptance it could be useful for monitoring fibrosis progression and regression in the individual case, but more data are awaited for this application. Guidelines are needed for the use of TE in clinical practice.

Performance of transient elastography for the staging of liver fibrosis: a meta-analysis

BACKGROUND & AIMS

Transient elastography has been studied in a multitude of liver diseases for the staging of liver fibrosis with variable results. A meta-analysis was performed to assess the overall performance of transient elastography for the diagnosis of liver fibrosis and to analyze factors influencing the diagnostic accuracy.

METHODS

Literature databases and international conference abstracts were searched. Inclusion criteria were as follows: evaluation of transient elastography, liver biopsy as reference, and assessment of the area under the receiver operating characteristic curve (AUROC). The meta-analysis was performed using the random-effects model for the AUROC, summary receiver operating curve techniques, as well as meta-regression approaches.

RESULTS

Fifty studies were included in the analysis. The mean AUROC for the diagnosis of significant fibrosis, severe fibrosis, and cirrhosis were 0.84 (95% confidence interval [CI], 0.82-0.86), 0.89 (95% CI, 0.88-0.91), and 0.94 (95% CI, 0.93-0.95), respectively. For the diagnosis of significant fibrosis a significant reduction of heterogeneity of the AUROC was found when differentiating between the underlying liver diseases (P < .001). Other factors influencing the AUROC were the scoring system used and the country in which the study was performed. Age, body mass index, and biopsy quality did not have a significant effect on the AUROC.

CONCLUSIONS

Transient elastography can be performed with excellent diagnostic accuracy and independent of the underlying liver disease for the diagnosis of cirrhosis. However, for the diagnosis of significant fibrosis, a high variation of the AUROC was found that is dependent on the underlying liver disease.

Elastography in hepatology

A common characteristic of all chronic liver diseases is the occurrence and progression of fibrosis toward cirrhosis. Consequently, liver fibrosis assessment plays an important role in hepatology. Besides its importance for prognosis, determining the level of fibrosis reveals the natural history of the disease and the risk factors associated with its progression, to guide the antifibrotic action of different treatments. Currently, in clinical practice, there are three available methods for the evaluation of liver fibrosis: liver biopsy, which is still considered to be the 'gold standard'; serological markers of fibrosis and their mathematical combination - suggested in recent years to be an alternative to liver biopsy - and, more recently, transient elastography (TE). TE is a new, simple and noninvasive method used to measure liver stiffness. This technique is based on the progressing speed of an elastic shear wave within the liver. Currently, there are only a few studies that have evaluated TE effectiveness in chronic liver diseases, mostly in patients infected with the hepatitis C virus. Further studies are needed in patients with chronic liver disease, to assess the effectiveness of the fibrosis treatment.

Transient elastography is unreliable for detection of cirrhosis in patients with acute liver damage

Transient elastography [FibroScan (FS)] is a rapid, noninvasive, and reproducible method for measuring liver stiffness, which correlates with the degree of liver fibrosis in patients with chronic hepatitis. Whether FS is useful in the detection of preexisting liver fibrosis/cirrhosis in patients presenting with acute liver damage is unclear. Patients with acute liver damage of different etiologies were analyzed. Liver stiffness was measured during the acute phase of the liver damage and followed up to the end of the acute phase. A total of 20 patients were included in the study. In 15 of the 20 patients, initial liver stiffness values measured by FS during the acute phase of the liver damage were suggestive of liver cirrhosis. However, none of these 15 patients showed any signs of liver cirrhosis in the physical examination, ultrasound examination, or liver histology [performed in 11 of 15 (73%) patients]. A significant difference was observed in the initial bilirubin levels (5.8 +/- 6.5 mg/dL versus 15.7 +/- 11.8 mg/dL; P = 0.042) and age (32.4 +/- 17.5 years versus 49.7 +/- 15.8 years; P = 0.042) between patients with liver stiffness below or above 12.5 kPa. Six patients with initially high liver stiffness were followed up to abatement of the acute hepatitic phase; in all of them, liver stiffness values decreased to values below the cutoff value for liver cirrhosis.

CONCLUSION

Transient elastography frequently yields pathologically high values in patients with acute liver damage and is unsuitable for detecting cirrhosis/fibrosis in these patients.

Biomarkers of hepatic fibrosis, fibrogenesis and genetic pre-disposition pending between fiction and reality

Fibrosis is a frequent, life-threatening complication of most chronic liver diseases. Despite major achievements in the understanding of its pathogenesis, the translation of this knowledge into clinical practice is still limited. In particular, non-invasive and reliable (serum-) biomarkers indicating the activity of fibrogenesis are scarce. Class I biomarkers are defined as serum components having a direct relation to the mechanism of fibrogenesis, either as secreted matrix-related components of activated hepatic stellate cells and fibroblasts or as mediators of extracellular matrix (ECM) synthesis or turnover. They reflect primarily the activity of the fibrogenic process. Many of them, however, proved to be disappointing with regard to sensitivity and speci-ficity. Up to now hyaluronan turned out to be the relative best type I serum marker. Class II biomarkers comprise in general rather simple standard laboratory tests, which are grouped into panels. They fulfil most criteria for detection and staging of fibrosis and to a lesser extent grading of fibrogenic activity. More than 20 scores are currently available, among which Fibrotest™ is the most popular one. However, the diagnostic use of many of these scores is still limited and standardization of the assays is only partially realized. Combining of panel markers in sequential algorithms might increase their diagnostic validity. The translation of genetic pre-disposition biomarkers into clinical practice has not yet started, but some polymorphisms indicate a link to progression and outcome of fibrogenesis. Parallel to serum markers non-invasive physical techniques, for example, transient elastography, are developed, which can be combined with serum tests and profiling of serum proteins and glycans.

Noninvasive assessment of liver fibrosis and portal hypertension with transient elastography

Hepatic fibrogenesis, the "final" common result of injury to the liver, is believed to be a critical factor leading to hepatic dysfunction and may be important in the pathogenesis of portal hypertension. Thus, accurate assessment of the degree of fibrosis is important clinically. For many years, examination of hepatic histopathology has been considered to be the "gold standard" tool used to assess fibrosis. However, liver biopsy is invasive, and in many instances not favored by patients or physicians. Thus, alternative approaches to measure liver fibrosis would be extremely attractive. To the extent that transient elastography is able to measure "liver stiffness," which is proportional to the degree of liver fibrosis, this technique holds great promise.

Ultrasound-based transient elastography for the detection of hepatic fibrosis: systematic review and meta-analysis

BACKGROUND & AIMS

Ultrasound-based transient elastography is a promising noninvasive alternative to liver biopsy for detecting hepatic fibrosis. However, its overall test performance in various settings remains unknown. The aims of this study were to perform a systematic review and meta-analysis of diagnostic accuracy studies comparing ultrasound-based transient elastography with liver biopsy for hepatic fibrosis.

METHODS

Electronic and manual bibliographic searches to identify potential studies were performed. Selection of studies was based on reported accuracy of ultrasound-based transient elastography compared with liver biopsy. Data extraction was performed independently by 2 reviewers. Meta-analysis combined the sensitivities, specificities, and likelihood ratios of individual studies. Extent and reasons for heterogeneity were assessed.

RESULTS

Nine studies in full publication were identified. For patients with stage IV fibrosis (cirrhosis), the pooled estimates for sensitivity were 87% (95% confidence interval [CI], 84%-90%), specificity 91% (95% CI, 89%-92%), positive likelihood ratio 11.7 (95% CI, 7.9-17.1), and negative likelihood ratio 0.14 (95% CI, 0.10-0.20). Among 7 investigations reporting patients with stages II-IV fibrosis, the pooled estimates for sensitivity were 70% (95% CI, 67%-73%), specificity 84% (95% CI, 80%-88%), positive likelihood ratio 4.2 (95% CI, 2.4-7.2), and negative likelihood ratio 0.31 (95% CI, 0.23-0.43). Diagnostic threshold (or cut-off value) bias was identified as an important cause of heterogeneity for pooled results in both patient groups.

CONCLUSIONS

Ultrasound-based transient elastography appears to be a clinically useful test for detecting cirrhosis.

Assessment of hepatic fibrosis with magnetic resonance elastography

BACKGROUND & AIMS

Accurate detection of hepatic fibrosis is crucial for assessing prognosis and candidacy for treatment in patients with chronic liver disease. Magnetic resonance (MR) elastography, a technique for quantitatively assessing the mechanical properties of soft tissues, has been shown previously to have potential for noninvasively detecting liver fibrosis. The goal of this work was to obtain preliminary estimates of the sensitivity and specificity of the technique in diagnosing liver fibrosis, and to assess its potential for identifying patients who potentially can avoid a biopsy procedure.

METHODS

MR elastography was performed in 35 normal volunteers and 50 patients with chronic liver disease. MR imaging measurements of hepatic fat to water ratios were obtained to assess the potential for fat infiltration to affect stiffness-based detection of fibrosis.

RESULTS

Liver stiffness increased systematically with fibrosis stage. Receiver operating curve analysis showed that, with a shear stiffness cut-off value of 2.93 kilopascals, the predicted sensitivity and specificity for detecting all grades of liver fibrosis is 98% and 99%, respectively. Receiver operating curve analysis also provided evidence that MR elastography can discriminate between patients with moderate and severe fibrosis (grades 2-4) and those with mild fibrosis (sensitivity, 86%; specificity, 85%). Hepatic stiffness does not appear to be influenced by the degree of steatosis.

CONCLUSIONS

MR elastography is a safe, noninvasive technique with excellent diagnostic accuracy for assessing hepatic fibrosis. Based on the high negative predictive value of MR elastography, an initial clinical application may be to triage patients who are under consideration for biopsy examination to assess possible hepatic fibrosis.

Transient elastography for the assessment of chronic liver disease: Ready for the clinic?

Transient elastography is a recently developed non-invasive technique for the assessment of hepatic fibrosis. The technique has been subject to rigorous evaluation in a number of studies in patients with chronic liver disease of varying aetiology. Transient elastography has been compared with histological assessment of percutaneous liver biopsy, with high sensitivity and specificity for the diagnosis of cirrhosis, and has also been used to assess pre-cirrhotic disease. However, the cut-off values between different histological stages vary substantially in different studies, patient groups and aetiology of liver disease. More recent studies have examined the possible place of transient elastography in clinical practice, including risk stratification for the development of complications of cirrhosis. This review describes the technique of transient elastography and discusses the interpretation of recent studies, emphasizing its applicability in the clinical setting.

Present and future therapeutic strategies in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is found in individuals who do not drink or abuse alcohol and represents a significant health burden for the general community. NAFLD is often associated with one or more features of the metabolic syndrome and has potential for evolution towards non-alcoholic steatohepatitis (NASH), the necro-inflammatory form of liver steatosis. The most worrisome evolutive events in a subgroup of NASH patients include advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. Pathophysiology of NAFLD/NASH is complex, but studies point to a pre-eminent role of oxidative stress and lipid peroxidation in the liver, including early mitochondrial dysfunction. Changes follow an insulin resistance status with a background of a chronic pro-inflammatory status due to an excess of visceral adiposity. Although no established therapy exists for NAFLD/NASH, potential therapeutic approaches are discussed in this review.

Noninvasive diagnosis of hepatic fibrosis in chronic hepatitis C

Assessment of hepatic fibrosis is important for determining prognosis, guiding management decisions, and monitoring disease. Histological evaluation of liver biopsy specimens is currently considered the reference test for staging hepatic fibrosis. Since liver biopsy carries a small but significant risk, noninvasive tests to assess hepatic fibrosis are desirable. This editorial gives an overview on noninvasive methods currently available to determine hepatic fibrosis and their diagnostic accuracy for predicting significant fibrosis and cirrhosis in chronic hepatitis C. Based on available data, the performance of simple tests derived from routine laboratory parameters appears to be similar to that of more complex and expensive fibrosis panels. Transient elastography seems more accurate than blood tests for diagnosing cirrhosis.

NASH and the risk of cirrhosis and hepatocellular carcinoma in type 2 diabetes

The risk of chronic liver disease and liver-related mortality is increased in patients with type 2 diabetes mellitus. Several cohort studies have suggested a metabolic pathway from nonalcoholic fatty liver, nonalcoholic steatohepatitis, cryptogenic cirrhosis, and eventually hepatocellular carcinoma. Although cardiovascular risk remains the major cause for excess mortality in type 2 diabetes mellitus, the risk of progressive liver disease should no longer be underscored.