Spleen stiffness: toward a noninvasive portal sphygmomanometer?

Shear wave elastography of the spleen using elastography point quantification: stiffness values in healthy children

PURPOSE

To evaluate the shear wave elastography (SWE) values of the spleen in healthy children using Elastography Point Quantification (ElastPQ).

METHODS

In this IRB approved prospective study, spleen stiffness was measured in 146 healthy children (2-15 years) using ElastPQ. SWE values were recorded in upper pole, mid pole, and lower pole of the spleen in all the children.

RESULTS

The mean (± SD) SWE values of the spleen in children in ≤ 5 years age group, > 5-10 years age group, and > 10-15 years age group were 5.6 (± 4.2) kPa, 6.5 (± 3.2) kPa, and 5.9 (± 3.6) kPa, respectively. No statistically significant difference was seen in SWE values of the spleen between these three groups (p > 0.5). The mean (± SD) SWE values in ≤ 10 years and > 10 years age group were 6.1 (± 3.6) kPa and 5.9 (± 2.6) kPa, respectively. No statistically significant difference was seen in SWE values of the spleen between these two groups (p > 0.5). There was no significant difference in the SWE values for boys and girls. Statistically significant difference was seen between the mean SWE values in the two groups based on the median splenic length, which was 5.5 (± 3.8) kPa in the group with a length of ≤ 7.6 cm and 6.7 (± 2.8) kPa in the group with a length of > 7.6 cm.

CONCLUSION

SWE values of the spleen in healthy children do not correlate with age, and no significant difference is there in the SWE values for boys and girls. There was a statistically significant difference in the SWE values of the spleen while comparing the groups based on the median splenic length.

Non-invasive assessment of fibrosis regression and portal hypertension in patients with advanced chronic hepatitis C virus (HCV)-associated liver disease and sustained virologic response (SVR): 3 years follow-up of a prospective longitudinal study

Long-term effects on cirrhosis and portal hypertension of direct antiviral agent (DAA)-based eradication of hepatitis C virus (HCV) are still under debate. We analysed dynamics of liver and spleen elastography to assess potential regression of cirrhosis and portal hypertension 3 years post-treatment. Fifty-four patients with HCV-associated cirrhosis and DAA-induced SVR were included. Liver and spleen stiffness were measured at baseline (BL), end of treatment (EOT), 24 weeks after EOT (FU24) and 1, 2 and 3 (FU144) years post-treatment by transient liver elastography (L-TE) and point shear wave elastography (pSWE) using acoustic radiation force impulse (ARFI) of the liver (L-ARFI) and spleen (S-ARFI). Biochemical, virological and clinical data were also obtained. Liver stiffness assessed by L-TE decreased between BL [median (range), 32.5(9.1-75) kPa] and EOT [21.3(6.7-73.5) kPa; p < .0001] and EOT and FU144 [16(4.1-75) kPa; p = .006]. L-ARFI values improved between EOT [2.5(1.2-4.1) m/s] and FU144 [1.7(0.9-4.1) m/s; p = .001], while spleen stiffness remained unchanged. Overall, L-TE improved in 38 of 54 (70.4%) patients at EOT and 29 of 38 (76.3%) declined further until FU144, whereas L-ARFI values decreased in 30/54 (55.6%) patients at EOT and continued to decrease in 28/30 (93.3%) patients at FU144. Low bilirubin and high albumin levels at BL were associated with improved L-ARFI values (p = .048) at EOT or regression of cirrhosis (<12.5 kPa) by L-TE at FU144 (p = .005), respectively. Liver stiffness, but not spleen stiffness, continued to decline in a considerable proportion of patients with advanced liver disease after HCV eradication.

Non-invasive splenic parameters of portal hypertension: Assessment and utility

BACKGROUND

Portal hypertension is a major complication of cirrhosis that is associated with significant morbidity and mortality. The present gold-standard method to risk stratify and observe cirrhosis patients with portal hypertension is hepatic venous pressure gradient measurement or esophagogastroduodenoscopy. However, these methods are invasive, carry a risk of complications and are associated with significant patient discomfort. Therefore, non-invasive splenic parameters are of clinical interest as potential useful markers in determining the presence of portal hypertension. However, diagnostic accuracy and reproducibility remains unvalidated.

AIM

To assess the diagnostic accuracy of spleen stiffness, area and diameter in predicting the presence of portal hypertension.

METHODS

Of 50 patients with varying liver disease pathologies were prospectively recruited from the St. Mary’s Hospital Liver Unit in London; 25 with evidence of portal hypertension and 25 with no evidence of portal hypertension. Liver stiffness, spleen stiffness, spleen diameter and spleen area were measured using the Philips Affiniti 70 elastography point quantification point shear wave elastography system. The aspartate aminotransferase-to-platelet-ratio-index (APRI) score was also calculated. Performance measures, univariate and multivariate logistic regression were used to evaluate demographic, clinical and elastography variables. Interclass correlation coefficient was used to determine the reproducibility of splenic area and diameter.

RESULTS

On univariate and individual performance, platelet count [area under the receiver operating characteristic (AUROC) 0.846, P value < 0.001], spleen area (AUROC 0.828, P value = 0.002) and APRI score (AUROC 0.827, P value < 0.001) were the most accurate variables in identifying the presence of portal hypertension. On multivariate logistic regression models constructed, the combination of spleen area greater than 57.90 cm² and platelet count less than 126 × 10⁹ had 63.2% sensitivity and 100% specificity, 100% positive predictive value and 100% negative predictive value. An alternative combination of spleen stiffness greater than 29.99 kPa and platelet count less than 126 × 10⁹ had 88% sensitivity, 75% specificity, 78.6% positive predictive value and 85.7% negative predictive value. An interclass correlation coefficient value of 0.98 (95%CI: 0.94-0.99, P value < 0.001) and 0.96 (95%CI: 0.91-0.99, P value < 0.001) were determined for inter-operator variability for spleen area and diameter respectively.

CONCLUSION

Spleen area, spleen stiffness and platelet count may be useful markers to assess the presence of portal hypertension in patients of various etiologies.

Clinical significance of spleen stiffness in patients with acute decompensated heart failure

Aims

Congestive splenomegaly is a classic sign of organ congestion in acute decompensated heart failure (ADHF). Shear wave elastography (SWE) allows the measurement of spleen stiffness (SS). We hypothesized that SS could quantify the severity of splenic congestion and predict adverse events in ADHF.

Methods and Results

This study included two cohorts: a haemodynamic cohort (62 HF patients) and an outcome cohort (115 ADHF patients). SS was measured by two‐dimensional SWE on the same day of right heart catheterization in the haemodynamic cohort. Right atrial pressure (RAP) independently correlated with SS (β = 0.32, P = 0.002). SS was measured in the outcome cohort before discharge. The 115 patients were divided into three groups on the basis of the tertile value of SS. The third tertile SS group had a higher prevalence of severe tricuspid regurgitation, higher N‐terminal B‐type natriuretic peptide (NT pro‐BNP), and larger right ventricular diastolic diameter, than had the first tertile group and the second tertile group. During a median follow‐up period of 105 (77–135) days, adverse events occurred in 25 patients (one death and 24 rehospitalizations for HF). The third tertile SS group had a significantly higher rate of adverse events (P < 0.001). A higher SS was independently associated with adverse events after adjusting for conventional validated risk score, liver function test, liver stiffness, and estimated RAP.

Conclusions

The degree of SS at discharge can be used as a marker of residual splenic congestion, which is predictive of adverse events in patients with ADHF.

Feasibility and reproducibility of liver and pancreatic stiffness in patients with alcohol-related liver disease

BACKGROUND

To date no studies evaluated liver stiffness and pancreatic stiffness by shear-wave elastography, in alcoholic liver disease setting.

AIMS

To assess feasibility and reproducibility of Shear-wave elastrography in measuring liver and pancreatic stiffness in alcoholic liver disease and investigate the correlation among liver and pancreatic stiffness and clinical data.

METHODS

Liver and pancreatic stiffness were measured by elastography (2 examiners) in patients with alcoholic liver disease and in healthy volunteers, for reference values. Effect of clinical data was evaluated on log-transformed pancreatic or liver stiffness, using univariate and multivariate linear regression model.

RESULTS

87 patients and 46 healthy volunteers enrolled. Both the stiffness values were higher in patients than healthy volunteers (p < 0.001). For liver stiffness: no failure measurements found, the Intraclass correlation coefficient (between 2 examiners) was 0.72 and the variables significantly correlated at multivariate analysis were cirrhosis (p < 0.0001) and steatosis (p = .007). For pancreatic stiffness: 2 failures found, with ICC 0.40 and the only variable significantly correlated at multivariate analysis was liver cirrhosis (p = .005).

CONCLUSIONS

Shear-wave elastography feasibility was good for liver and pancreatic stiffness. Reproducibility was good for liver stiffness, whereas fair for pancreatic one. Both the stiffness correlated with alcoholic liver disease severity. Elastography could be a useful tool to detect and monitor alcohol-related liver and pancreatic damage.

Spleen stiffness to liver stiffness ratio significantly differs between ALD and HCV and predicts disease-specific complications

Background & Aims

Both liver stiffness (LS) and spleen stiffness (SS) are widely used to non-invasively assess liver fibrosis and portal hypertension, respectively. We aimed to identify the impact of disease etiology, namely the localization of inflammation (portal vs. lobular), on the SS/LS ratio.

Methods

In this multicenter study, LS and SS were prospectively assessed in 411 patients with alcohol-related liver disease (ALD) or hepatitis C virus (HCV) using FibroScan® (Echosens, Paris); changes in these parameters were also studied in response to treatment (alcohol withdrawal, HCV therapy). LS and spleen length (SL) were further analyzed in a retrospective cohort of 449 patients with long-term data on decompensation/death.

Results

Both, SS and SL were significantly higher in HCV compared to ALD (42.0 vs. 32.6 kPa, p≪0.0001, 15.6 vs. 11.9 cm, p≪0.0001) despite a lower mean LS in HCV. Consequently, the SS to LS ratio and the SL to LS ratio were significantly higher in HCV (3.8 vs. 1.72 and 1.46 vs. 0.86, p≪0.0001) through all fibrosis stages. Notably, SL linearly increased with SS and the relation between SS and SL was identical in HCV and ALD. In contrast, livers were much larger in ALD at comparable LS. After treatment, LS significantly decreased in both diseases without significant changes to the SS/LS ratio. In the prognostic cohort, patients with ALD had higher LS values (30.5 vs. 21.3 kPa) and predominantly presented with jaundice (65.2%); liver failure was the major cause of death (p≪0.01). In contrast, in HCV, spleens were larger (17.6 vs. 12.1 cm) while variceal bleeding was the major cause of decompensation (73.2%) and death (p≪0.001).

Conclusion

Both SS/LS and SL/LS ratios are significantly higher in patients with portal HCV compared to lobular ALD. Thus, combined LS and SS or SL measurements provide additional information about disease etiology and disease-specific complications.

Lay summary

Herein, we show that patients with hepatitis C virus infection (HCV) have higher spleen stiffness and portal pressure than patients with alcohol-related liver disease (ALD), within the same fibrosis stage and matched to liver stiffness. Thus, the spleen stiffness to liver stiffness ratio is significantly higher in patients with HCV compared to ALD. Additionally, patients with HCV more commonly progress to portal hypertension-related complications (e.g. variceal bleeding), while patients with ALD more commonly progress to liver failure (e.g. jaundice). The spleen stiffness to liver stiffness ratio is a useful tool to confirm disease etiology and predict disease-specific complications.

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SS/LS ratio is significantly higher in patients with portal HCV compared to lobular ALD.

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Patients with HCV have higher SS and portal pressure than patients with ALD and the same LS.

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Patients with HCV die earlier from portal hypertension-related complications.

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Patients with ALD die earlier from liver failure.

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Combined LS and SS measurements provide extra information about disease etiology and disease-specific complications.

Comparison of physical parameter measurements between peripheral and portal blood samples in patients with portal hypertension

BACKGROUND

Measuring portal venous pressure is necessary to examine, diagnose, and treat portal hypertension, but current methods are invasive.

OBJECTIVE

This study aimed to determine whether a noninvasive peripheral blood measurement could be used to estimate portal venous pressure by investigating correlations between certain physical parameter measurements in the peripheral blood with those obtained in portal blood samples.

METHODS

A total of 128 peripheral and portal blood samples from patients (n= 128) were analyzed for blood rheology and routine blood parameters.

RESULTS

The mean peripheral and portal whole blood viscosities under the shear rates of 200 s-1 (BV 200 s-1) were 2.97 ± 0.50 mPa.s and 3.06 ± 0.39 mPa.s. The mean peripheral and portal BV 30 s-1 values were 3.96 ± 0.79 mPa.s and 4.16 ± 0.64 mPa.s. We observed strong correlations between peripheral and portal blood measurements of BV 200 s-1 (r2= 0.9649), BV 30 s-1 (r2= 0.9622), BV 5 s-1 (r2= 0.9610), and BV 1 s-1 (r2= 0.9623).

CONCLUSIONS

Our results indicate that peripheral blood can be used to evaluate certain parameters in portal blood for use in biofluid mechanics studies, and to provide noninvasive measurement of portal venous pressure.

The spleen in liver cirrhosis: revisiting an old enemy with novel targets

The spleen is a secondary lymphoid organ which can influence the progression of multiple diseases, notably liver cirrhosis. In chronic liver diseases, splenomegaly and hypersplenism can manifest following the development of portal hypertension. These splenic abnormalities correlate with and have been postulated to facilitate the progression of liver fibrosis to cirrhosis, although precise mechanisms remain poorly understood. In this review, we summarize the literature to highlight the mechanistic contributions of splenomegaly and hypersplenism to the development of liver cirrhosis, focusing on three key aspects: hepatic fibrogenesis, hepatic immune microenvironment dysregulation and liver regeneration. We conclude with a discussion of the possible therapeutic strategies for modulating splenic abnormalities, including the novel potential usage of nanomedicine in non-surgically targetting splenic disorders for the treatment of liver cirrhosis.

Noninvasive tools and risk of clinically significant portal hypertension and varices in compensated cirrhosis: The "Anticipate" study

In patients with compensated advanced chronic liver disease (cACLD), the presence of clinically significant portal hypertension (CSPH) and varices needing treatment (VNT) bears prognostic and therapeutic implications. Our aim was to develop noninvasive tests-based risk prediction models to provide a point-of-care risk assessment of cACLD patients. We analyzed 518 patients with cACLD from five centers in Europe/Canada with paired noninvasive tests (liver stiffness measurement [LSM] by transient elastography, platelet count, and spleen diameter with calculation of liver stiffness to spleen/platelet score [LSPS] score and platelet-spleen ratio [PSR]) and endoscopy/hepatic venous pressure gradient measurement. Risk of CSPH, varices, and VNT was modeled with logistic regression. All noninvasive tests reliably identified patients with high risk of CSPH, and LSPS had the highest discrimination. LSPS values above 2.65 were associated with risks of CSPH above 80%. None of the tests identified patients with very low risk of all-size varices, but both LSPS and a model combining TE and platelet count identified patients with very low risk (<5%) risk of VNT, suggesting that they could be used to triage patients requiring screening endoscopy. LSPS values of <1.33 were associated with a <5% risk of VNT, and 26% of patients had values below this threshold. LSM combined with platelet count predicted a risk <5% of VNT in 30% of the patients. Nomograms were developed to facilitate point-of-care risk assessment.

CONCLUSION

A significant proportion of patients with a very high risk of CSPH, and a population with a very low risk of VNT can be identified with simple, noninvasive tests, suggesting that these can be used to individualize medical care. (Hepatology 2016;64:2173-2184).

Spleen Stiffness Is Superior to Liver Stiffness for Predicting Esophageal Varices in Chronic Liver Disease: A Meta-Analysis

Background and Aims

Liver stiffness (LS) and spleen stiffness (SS) are two most widely accessible non-invasive parameters for predicting esophageal varices (EV), but the reported accuracy of the two predictors have been inconsistent across studies. This meta-analysis aims to evaluate the diagnostic performance of LS and SS measurement for detecting EV in patients with chronic liver disease (CLD), and compare their accuracy.

Methods

Pubmed/Medline, Embase, Cochrane Library and Ovid were searched for all studies assessing SS and LS simultaneously in EV diagnosis. A total of 16 studies including 1892 patients were included in this meta-analysis, and the pooled statistical parameters were calculated using the bivariate mixed effects models.

Results

In detection of any EV, for LS measurement, the summary sensitivity was 0.83 (95% confidence interval [CI]: 0.78–0.87), and the specificity was 0.66 (95% CI: 0.60–0.72). While for SS measurement, the pooled sensitivity and specificity was 0.88 (95% CI: 0.83–0.92) and 0.78 (95% CI: 0.73–0.83). The summary receiver operating characteristic (SROC) curve values of LS and SS were 0.81 (95% CI: 0.77–0.84) and 0.88 (95% CI: 0.85–0.91) respectively, and the results had statistical significance (P<0.01). The diagnostic odds ratio (DOR) of SS (25.73) was significantly higher than that of LS (9.54), with the relative DOR value was 2.48 (95%CI: 1.10–5.60), P<0.05.

Conclusions

Under current techniques, SS is significantly superior to LS for identifying the presence of EV in patients with CLD. SS measurement may help to select patients for endoscopic screening.

Shear wave elastography of the spleen: evaluation of spleen stiffness in healthy volunteers

Purpose

The aim of this study was to assess the mean value of spleen stiffness measured by Shear wave elastography in healthy patients and its dependence on age, sex, and spleen dimensions, and to evaluate the repeatability of this method.

Methods

The final study group included 59 healthy volunteers without any clinical evidence of liver disease, portal hypertension, hematological disorders, and without any pathological ultrasonographic spleen findings. Each patient underwent abdominal ultrasound examination and elastography of the liver and the spleen.

Results

The mean value of spleen stiffness was 16.6 ± 2.5 kPa. In the group of men (N = 25), it was 17.3 ± 2.7 kPa, and in the group of women (N = 34), it was 16.1 ± 2.2 kPa. The study confirmed no correlation between spleen stiffness and sex, age of patients, and spleen size. Coefficient of repeatability and correlation coefficient between the results of the first and the second measurement showed good but not ideal repeatability of the measurement results.

Conclusion

Our outcomes may be a reference point for evaluating spleen stiffness in research on patients with various illnesses.

Clinical Evaluation and Prognosis

BACKGROUND

Liver cirrhosis is no longer considered a homogeneous disease, with two different phases now identified: 'compensated' and 'decompensated' cirrhosis, in which complications of cirrhosis characterize the latter. Within each phase, different stages and predictors should be recognized in order to correctly stratify the prognosis and individualize possible therapeutic options. Key Messages: In compensated cirrhosis the presence of clinically significant portal hypertension [CSPH = hepatic venous pressure gradient (HVPG) ≥10 mm Hg] constitutes the most important independent predictor of several relevant clinical endpoints (formation of esophageal varices; first clinical decompensation). An optimal HVPG response to medical therapy of portal hypertension (HVPG reduction <12 mm Hg or ≥20% vs. the pretreatment value, responders) has been consistently linked to a decrease in the risk of variceal bleeding both in primary and secondary prophylaxis, and to a decrease in the risk of presenting other clinical decompensating events. Furthermore, in patients undergoing secondary prophylaxis of variceal bleeding, being an HVPG responder is associated with an improved survival. HVPG also maintains an independent prognostic value in patients with decompensated cirrhosis. Noninvasive alternatives to HVPG for the prediction of CSPH have been investigated; liver stiffness by transient elastography and the combination of liver stiffness, spleen size by ultrasound and platelet count are currently the best methods to noninvasively diagnose CSPH, with an accuracy of about 90%. Additional factors modulate prognosis in cirrhosis. Liver function (albumin, bilirubin, INR) is independently associated with prognosis both in compensated and decompensated cirrhosis, and in the latter phase renal function also plays a central role. Among clinical cofactors, obesity and diabetes are emerging as variables increasing the risk of progression to decompensation and death in cirrhosis.

CONCLUSIONS

Prognostic stratification in patients with cirrhosis should take into account a complex interplay of several clinical, hemodynamic and biological variables. The present review summarizes the existing evidence regarding prognostic factors in cirrhosis, with particular emphasis on compensated cirrhosis.

Cirrhosis and portal hypertension: The importance of risk stratification, the role of hepatic venous pressure gradient measurement

Portal hypertension is the main prognostic factor in cirrhosis. The recent emergence of potent antiviral drugs and new algorithm of treatment for the management of complications due to portal hypertension have sensibly changed our perception of cirrhosis that can be now considered as a multistage liver disease whose mortality risk can be reduced by a tailored approach for any stage of risk. Experts recommend to move toward a pathophysiological classification of cirrhosis that considers both structural and functional changes. The hepatic venous pressure gradient HVPG, is the reference gold standard to estimate the severity of portal hypertension in cirrhosis. It correlates with both structural and functional changes that occur in cirrhosis and carries valuable prognostic information to stratify the mortality risk. This article provides a general overview of the pathophysiology and natural course of cirrhosis and portal hypertension. We propose a simplified classification of cirrhosis based on low, intermediate and high mortality stage. The prognostic information provided by HVPG is presented according to each stage. A comparison with prognostic models based on clinical and endoscopic variables is discussed in order to evidence the additional contribute given by HVPG on top of other clinical and instrumental variables widely used in clinical practice.

Ultrasound point shear wave elastography assessment of liver and spleen stiffness: effect of training on repeatability of measurements

OBJECTIVES

To evaluate reproducibility of measurements of spleen stiffness (SS) and liver stiffness (LS) at several sites by using point shear wave elastography (pSWE) and to investigate any training effect.

METHODS

Healthy volunteers were consecutively enrolled. Measurements of SS and LS were performed by an expert (observer 1) and a novice (observer 2) at three different sites of liver and spleen. To assess the effect of training the study was conducted in two periods (period 1 and period 2). Concordance correlation coefficient was used to assess intra-observer and inter-observer reproducibility.

RESULTS

A total of 92 subjects (67 men and 25 women) were enrolled in the study. Both intra-observer and inter-observer agreement were higher for the liver than for the spleen. Overall, the highest intra-observer and inter-observer agreement were obtained for the assessment of LS through intercostal space, and for measurements at this site there was a significantly better performance of observer 2 after the training period. For both observers, training improved the repeatability of SS measurements at all sites. A good intra-observer agreement was obtained only for measurements at the spleen lower pole.

CONCLUSIONS

The results of this study show that a learning curve in pSWE acquisition should be taken into account both for SS and LS measurements.

KEY POINTS

Reproducibility of SS measurements depends on the expertise of the operator. To achieve good reproducibility between measurements a training period is required. A learning curve in pSWE acquisition should be taken into account. SS measurements are less reproducible than LS measurements.

Transient elastography: Kill two birds with one stone?

Assessment of liver fibrosis and steatosis is crucial in chronic liver diseases in order to determine the prognosis, the need of treatment, as well as monitor disease progression and response to treatment. Liver biopsy is limited by its invasiveness and patient acceptability. Transient elastography (TE, Fibroscan^®) is a non-invasive tool with satisfactory accuracy and reproducibility to estimate liver fibrosis and steatosis. TE has been well validated in major liver diseases including chronic hepatitis B and C, non-alcoholic fatty liver disease, alcoholic liver disease, primary biliary cirrhosis, and primary sclerosing cholangitis. As alanine aminotransferase (ALT) is one of the major confounding factors of liver stiffness in chronic hepatitis B, an ALT-based algorithm has been developed and higher liver stiffness measurements (LSM) cutoff values for different stages of liver fibrosis should be used in patients with elevated ALT levels up to 5 times of the upper limit of normal. Otherwise falsely-high LSM results up to cirrhotic range may occur during ALT flare. TE is also useful in predicting patient prognosis such as development of hepatocellular carcinoma (HCC), portal hypertension, post-operative complications in HCC patients, and also survival. Unfortunately, failed acquisition of TE is common in obese patients. Furthermore, obese patients may have higher LSM results even in the same stage of liver fibrosis. The new XL probe, a larger probe with lower ultrasound frequency and deeper penetration, increases the success rate of TE in obese patients. The median LSM value with XL probe was found to be lower than that by the conventional M probe, hence cutoff values approximately 1.2 to 1.3 kPa lower than those of M probe should be adopted. Recent studies revealed a novel ultrasonic controlled attenuation parameter (CAP) of the machine is a useful parameter to detect even low-grade steatosis noninvasively. CAP may also be used to quantify liver steatosis by applying different cutoff values. As both LSM and CAP results are instantly available at same measurement, this makes TE a very convenient tool to assess any patients who are suspected or confirmed to suffer from chronic liver diseases.