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Cheng et al. Advances in liver fibrosis

scanner, no additional cost is required. [30] The ARFI the signals received by the MR machine. [43] There are
not only shows the degree of fibrosis, it also provides still limited studies mentioning the clinical significance
external information for disease progression for different of MRE results. Even though it is apparently sensitive
chronic liver disease, for example HCV. [31] Another to mild liver fibrosis, the result may sometimes be
advantage of this tool is that it can provide real-time unreliable. [44]
results and easy to perform. The measurement results
appear to be more accurate in overweight and obese Serum test formulae
patients, compared with transient elastography. [32] Common laboratory parameters
However, one prominent disadvantage for ARFI is that Another commonly adopted non-invasive assessment
the range of its measurement is quite narrow (only from is based on serum with or without clinical parameters.
0.5 to 4.4 m/s). [33] Furthermore, it is quite difficult to Examples including common parameters in clinical
match the degree of fibrosis with the wave propagation practice include aspartate aminotransferase (AST) to
speed, i.e. a cut-off, which is difficult to be defined. [34] platelet ratio index (APRI), [45] Forns index, [46] Fibrosis-4
(FIB-4), [47] Fibroindex, [48] Hui index, [49] NAFLD fibrosis
SWE score (NFS) [50] and BAAT score [51] [Table 1]. These
SWE is a 2-dimensional ultrasound technique based parameters are derived from routine liver biochemistry
on the estimation of shear wave velocity from the panel, so it is quite convenient. These parameters are
radiation force of a focused beam of ultrasound, [35] also technically easy to obtain and with minimal inter-
and it can be converted results in terms of kPa by an observer variations. Patients with advanced fibrosis
equation. [36] No extra vibrator or detector is required as can be identified by these tests. [52] However, these
it is integrated into a conventional ultrasound system. parameters are often validated in just one or two liver
Besides, elasticity of liver tissues can be shown in diseases. For example, two scoring systems for CHC
both numerical values and color (i.e. higher stiffness patients, namely APRI and FIB-4, are found to be not
is reflected in red color), which can reflect the relative useful in CHB patients. [53]
stiffness of the liver tissue quickly. The numerical values
can be expressed in either kPa or m/s, which can be FibroTest ®
comparable with the results from transient elastography Some specific biochemical parameters related
or ARFI. [37] Actually, its accuracy is higher compared to fibrinolysis or fibrinogenesis are developed to
to transient elastography or AFRI in assessing the improve the specificity of liver fibrosis assessment
degree of fibrosis, especially in those with early-stage [Table 2]. One example is FibroTest (BioPredictive,
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liver fibrosis. [38] SWE with spleen stiffness index is Paris, France; or known as Fibrosure in the United
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recommended as the first line assessment for patients States ) consists of 5 components, namely GGT, total
with liver fibrosis due to chronic hepatitis C in the latest bilirubin, α-2 macroglobulin, apolipoprotein A1, and
guidelines. [39] However, only a few studies validate its haptoglobin. Sometimes, another test, ActiTest, would
clinical application. [38,40] also perform together with FibroTest for assessment
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for liver activity, with the additional measurement of
MRE ALT. The results would be adjusted according to age
MRE adopts a phase contrast imaging method which and gender. [54] FibroTest is originally used in patients
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depends on mechanical wave propagation to assess with CHC. [55] Nowadays it is recommended by different
the degree of liver stiffness. [41] Generally, MRE is less associations concerning liver studies for evaluation of
operator-dependent and involved in less technical liver fibrosis in patients with CHB, NAFLD or alcoholic
failure. The global picture of the liver can be viewed liver disease. [56-58] It is highly reliable and applicable, [59]
easily, regardless the obesity or severity of the ascites even for patients with obesity. [60] It performs well for
of the patients. It can also give a comprehensive diagnosis of liver cirrhosis for disease entities other
assessment for the associated complications, for than CHC. However, the results are suboptimal for
example portal hypertension or associated spleen detecting earlier stages before cirrhosis. [61]
stiffness. [42] Meanwhile, it is useful for diagnosis
and staging of liver fibrosis, even if the fibrosis is FibroMeter ®
very mild. Another advantage for MRE is that the FibroMeter (Echosens, Paris, France) has been
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results are readily reproducible. [42] However, MRE validated in patients with CHB, CHC, NAFLD and
is more expensive and time-consuming compared alcoholic liver disease. [62] Platelets, prothrombin index,
to ultrasound-based approach. Respiration creates AST, α-2 macroglobulin, hyaluronate, urea and age
artifacts on the images. Another important limitation is are taken into accounts. [63] Second generation (2G)
that it is not applicable on patients with iron overload, or has put age into another important parameter. [62]
hemochromatosis, because iron might create noise for FibroMeter has recently reached its third generation
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158 Hepatoma Research ¦ Volume 3 ¦ August 08, 2017