**5. Confounding factors influencing the interpretation of liver stiffness values**

Since the liver is self-contained in the non extensible Glisson's capsule, stiffness is definitive‐ ly influenced by pressure that can be either hydrostatic or osmotic [68]. There are a few con‐ ditions that may determine false results in situations where other factors, except from fibrosis, are influencing liver stiffness.

*Extra-hepatic cholestasis*. The impact of extrahepatic cholestasis on liver stiffness was re‐ cently demonstrated by Milloning [80] by evaluating cholestasis before endoscopic retro‐ grade cholangiopancreatography as well as 3 and 12 days after the procedure, in a study group of patients with cholestasis caused mainly by a neoplastic invasion of the biliary tree. If initially liver stiffness had values close to cirrhosis values (a mean of 15.2 kPa), af‐ ter drainage, the LS decreased as low as 7 kPa, in parallel with a decrease in values of bi‐ lirubin of 2.8-2.9 mg/dl. In all patients that underwent biliary drainage, the decrease of liver stiffness correlated with that of the bilirubin values, with a mean of decrease of 1.2 ±0.56 kPa for a reduction of the bilirubin of 1g/dl. The relationship between liver stiff‐ ness and cholestasis was afterwards reproduced in the same study on an animal model that underwent ligation of the biliary duct. This resulted in an elevation of liver stiffness from 4.6 kPa to 8.8 kPa in the first 120 minutes after ligation and a decrease in stiffness to 6.1 kPa within the first 30 minutes after decompression. In conclusion, it is indicated that before an interpretation of the stiffness measurements is performed, an eventual ex‐

Non-Invasive Evaluation of Liver Steatosis, Fibrosis and Cirrhosis in Hepatitis C Virus Infected Patients Using

Unidimensional Transient Elastography (Fibroscan®)

http://dx.doi.org/10.5772/52621

221

trahepatic cholestasis must be excluded using imaging investigations and lab tests.

efficacy, as liver stiffness decreases once cardiac compensation is achieved.

measure of portal venous pressure is not reliable enough [89].

**spleen stiffness measurements**

*Congestive heart failure* may lead to an increased liver stiffness, with values similar to cirrho‐ sis, because of the elevated blood content of the liver, in 60% of the patients [80-84]. In the context of cardiopulmonary conditions, TE may be relevant for the evaluation of treatment

**6. Optimizing the non-invasive diagnosis of portal hypertension using**

Splenomegaly is a common finding in liver cirrhosis that should determine changes in spleen density as well, because of tissue hyperplasia and fibrosis [85, 86], and/or because of portal and splenic congestion due to the splanchnic hyper-dynamic state [87]. These changes might be quantified by elastography. Until recently, only magnetic resonance elastography (MRE) was used with encouraging results in this respect [88]. The preliminary data showed a highly significant correlation between liver and spleen stiffness in patients with portal hy‐ pertension, but, according to the authors, the validity of spleen stiffness as noninvasive

**6.1. Principle of TE for Spleen Stiffness Measurements (SSM) and technique assessment**

Our group proposed for the first time the use of FibroScan® for spleen stiffness measure‐ ment (SSM) [90]. For the measurement itself we proposed the same procedure as for the liv‐ er stiffness measurement, with the sole exception that the patient had his left arm in maximum abduction and the transducer was placed in the left intercostal spaces, usually on the posterior axillary line. For better locating the splenic parenchyma, we also used ultra‐ sound guidance, so that we could choose the best location for performing the analysis.

*Necroinflammatory activity* proved to influence liver stiffness in patients with viral hepatitis, causing an increase in stiffness in parallel with the grade of histological activity [29, 69, 70]. In agreement with these results, the risk of overestimating the stage of fibrosis may occur in pa‐ tients with acute hepatitis or reactivated chronic hepatitis, if just the value of liver stiffness is con‐ sidered. Recent studies demonstrated that tissue alterations associated with acute hepatitis in a patient with no liver disease history produce a significant growth of liver stiffness, sometimes reaching cirrhosis values; this is due either to cellular intumescence or to severe cholestasis [71]. The contribution of these non-fibrotic changes upon liver stiffness was demonstrated by the pro‐ gressive reduction of liver stiffness parallel with the decrease of the transaminases [72, 73].

On the other hand, in patients with reactivated chronic hepatitis (therefore with preexisting fibrosis), the increased stiffness is not caused by fibrosis alone, but also by the added cellular intumescence [74].

From a practical perspective, it is important that the values of liver stiffness in patients with acute hepatitis or in those with reactivated chronic hepatitis must be interpreted carefully, within the patient's clinical and biochemical context [75]. In these patients, a certain diagno‐ sis of severe fibrosis or cirrhosis cannot be established. The right management in these cases is to wait until the transaminases come back to normal and only when the potential involve‐ ment of inflammation is removed, the real status of fibrosis can be determined; it can thus be established whether the event was an acute hepatitis on a diseased liver or a chronic hepati‐ tis with pre-existing fibrosis that was reactivated [76].

At the same time, in patients with acute hepatitis, the evaluation of liver stiffness at various time intervals, can indicate the evolutive pattern of the condition, that may be characterized either by evolution towards fulminant hepatitis (significant increase in LS), or by remission (decrease in LS) [77].

*Liver steatosis*. The influence of steatosis on liver stiffness remains controversial. In some studies, steatosis did not have a significant impact on liver stiffness, even after adjusting for fibrosis stage [16, 24, 28]. Still, in these studies, the proportion of patients with severe steato‐ sis was too low to reliably quantify a possible influence and therefore further studies are necessary to clarify this aspect.

We noticed from our experience that, after performing a stratified analysis of liver stiffness for each stage of fibrosis, for the same grade of necroinflammatory activity (moderate-severe), the presence of steatosis lead to a significant increase in LS from 5.89 ± 1.64 kPa to 7.15 ± 2.67 kPa for those with stage F1 Metavir (p=0.004), and from 7.23±2.74 to 8.55±4.67 kPa for those with stage F2 (p=0.04) [78]. Besides, our studies have demonstrated that fibrosis is indeed the main predictor of liver stiffness, but activity and steatosis cannot be neglected and may explain the LS variability within the same fibrosis stage [25]. Afterwards, Ziol et al, using computer analysis of the micro‐ scopic image on a group of 152 patients, confirmed that steatosis clearly influences liver stiffness independently from fibrosis, an influence that is insignificant in patients with cirrhosis, but im‐ portant in non-cirrhosis patients [79].

*Extra-hepatic cholestasis*. The impact of extrahepatic cholestasis on liver stiffness was re‐ cently demonstrated by Milloning [80] by evaluating cholestasis before endoscopic retro‐ grade cholangiopancreatography as well as 3 and 12 days after the procedure, in a study group of patients with cholestasis caused mainly by a neoplastic invasion of the biliary tree. If initially liver stiffness had values close to cirrhosis values (a mean of 15.2 kPa), af‐ ter drainage, the LS decreased as low as 7 kPa, in parallel with a decrease in values of bi‐ lirubin of 2.8-2.9 mg/dl. In all patients that underwent biliary drainage, the decrease of liver stiffness correlated with that of the bilirubin values, with a mean of decrease of 1.2 ±0.56 kPa for a reduction of the bilirubin of 1g/dl. The relationship between liver stiff‐ ness and cholestasis was afterwards reproduced in the same study on an animal model that underwent ligation of the biliary duct. This resulted in an elevation of liver stiffness from 4.6 kPa to 8.8 kPa in the first 120 minutes after ligation and a decrease in stiffness to 6.1 kPa within the first 30 minutes after decompression. In conclusion, it is indicated that before an interpretation of the stiffness measurements is performed, an eventual ex‐ trahepatic cholestasis must be excluded using imaging investigations and lab tests.

ditions that may determine false results in situations where other factors, except from

*Necroinflammatory activity* proved to influence liver stiffness in patients with viral hepatitis, causing an increase in stiffness in parallel with the grade of histological activity [29, 69, 70]. In agreement with these results, the risk of overestimating the stage of fibrosis may occur in pa‐ tients with acute hepatitis or reactivated chronic hepatitis, if just the value of liver stiffness is con‐ sidered. Recent studies demonstrated that tissue alterations associated with acute hepatitis in a patient with no liver disease history produce a significant growth of liver stiffness, sometimes reaching cirrhosis values; this is due either to cellular intumescence or to severe cholestasis [71]. The contribution of these non-fibrotic changes upon liver stiffness was demonstrated by the pro‐ gressive reduction of liver stiffness parallel with the decrease of the transaminases [72, 73].

On the other hand, in patients with reactivated chronic hepatitis (therefore with preexisting fibrosis), the increased stiffness is not caused by fibrosis alone, but also by the added cellular

From a practical perspective, it is important that the values of liver stiffness in patients with acute hepatitis or in those with reactivated chronic hepatitis must be interpreted carefully, within the patient's clinical and biochemical context [75]. In these patients, a certain diagno‐ sis of severe fibrosis or cirrhosis cannot be established. The right management in these cases is to wait until the transaminases come back to normal and only when the potential involve‐ ment of inflammation is removed, the real status of fibrosis can be determined; it can thus be established whether the event was an acute hepatitis on a diseased liver or a chronic hepati‐

At the same time, in patients with acute hepatitis, the evaluation of liver stiffness at various time intervals, can indicate the evolutive pattern of the condition, that may be characterized either by evolution towards fulminant hepatitis (significant increase in LS), or by remission

*Liver steatosis*. The influence of steatosis on liver stiffness remains controversial. In some studies, steatosis did not have a significant impact on liver stiffness, even after adjusting for fibrosis stage [16, 24, 28]. Still, in these studies, the proportion of patients with severe steato‐ sis was too low to reliably quantify a possible influence and therefore further studies are

We noticed from our experience that, after performing a stratified analysis of liver stiffness for each stage of fibrosis, for the same grade of necroinflammatory activity (moderate-severe), the presence of steatosis lead to a significant increase in LS from 5.89 ± 1.64 kPa to 7.15 ± 2.67 kPa for those with stage F1 Metavir (p=0.004), and from 7.23±2.74 to 8.55±4.67 kPa for those with stage F2 (p=0.04) [78]. Besides, our studies have demonstrated that fibrosis is indeed the main predictor of liver stiffness, but activity and steatosis cannot be neglected and may explain the LS variability within the same fibrosis stage [25]. Afterwards, Ziol et al, using computer analysis of the micro‐ scopic image on a group of 152 patients, confirmed that steatosis clearly influences liver stiffness independently from fibrosis, an influence that is insignificant in patients with cirrhosis, but im‐

fibrosis, are influencing liver stiffness.

220 Liver Biopsy – Indications, Procedures, Results

tis with pre-existing fibrosis that was reactivated [76].

intumescence [74].

(decrease in LS) [77].

necessary to clarify this aspect.

portant in non-cirrhosis patients [79].

*Congestive heart failure* may lead to an increased liver stiffness, with values similar to cirrho‐ sis, because of the elevated blood content of the liver, in 60% of the patients [80-84]. In the context of cardiopulmonary conditions, TE may be relevant for the evaluation of treatment efficacy, as liver stiffness decreases once cardiac compensation is achieved.
