ARFI elastography of the spleen is inferior to liver elastography for the detection of portal hypertension

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.

Noninvasive Detection of Clinically Significant Portal Hypertension in Compensated Advanced Chronic Liver Disease

Patients with compensated advanced chronic liver disease have different prognoses depending on the presence of portal hypertension. Current non-invasive diagnostic methods allow identification of clinically significant portal hypertension. Portosystemic collaterals on imaging or liver stiffness of more than 20 to 25 kPa by using transient elastography identifies patients with clinically significant portal hypertension. Patients with liver stiffness of less than 20 kPa and platelet count of greater than 150 g/L can avoid endoscopy. This rule could be expanded using spleen stiffness. Methods to risk stratify for portal hypertension in compensated advanced chronic liver disease and successfully treated chronic hepatitis C and B are subject of research.

Noninvasive scores for the prediction of esophageal varices and risk stratification in patients with cirrhosis

The primary purpose of variceal screening in patients with cirrhosis is to detect gastroesophageal varices at high risk of hemorrhage and implement preventative intervention(s). It was previously recommended that all patients with cirrhosis undergo initial and periodic longitudinal variceal screening via upper endoscopy. However, there has been growing interest and methods to identify patients with cirrhosis who may not have clinically significant portal hypertension and therefore be unlikely to have varices requiring intervention or benefit from upper endoscopy. Because the population of patients with compensated advanced chronic liver disease continues to grow, it is neither beneficial nor cost-effective to perform endoscopic variceal screening in all patients. Therefore, there is ongoing research into the development of methods to non-invasively risk stratify patients with cirrhosis for the presence of high-risk esophageal varices and effectively limit the population that undergoes endoscopic variceal screening. This is particularly important and timely in light of increasing healthcare reform and barriers to healthcare. In this review, we discuss and compare, with respect to test characteristics and clinical applicability, the available methods used to non-invasively predict the presence of esophageal varices.

Portal pressure monitoring-state-of-the-art and future perspective

Portal hypertension is a serious symptom of chronic liver diseases, which can lead to many critical complications, such as the formation of varices related to upper digestive bleeding, ascites, infection, hepatic encephalopathy, renal failure, and even death. As a result, portal pressure monitoring has important prognostic and clinical implications. The hepatic venous pressure gradient measurement, a gold-standard method applied to monitor portal pressure, is invasive and only available in experienced centers. Over the past decade, noninvasive methods aimed at monitoring the portal pressure have been increasingly investigated, including serum markers, radiological features, ultrasound elastography, doppler and contrast-enhanced ultrasonography. In this study, we focused on both invasive and noninvasive methods for portal pressure monitoring and explored their roles in clinical setting. The advantages and limitations of various techniques for future research are also discussed.

Performance of spleen stiffness measurement in prediction of clinical significant portal hypertension: A meta-analysis

AIM

Our purpose was to evaluate the correlation between spleen stiffness (SS) measured by ultrasound-based elastography and hepatic venous pressure gradient (HVPG) and assess the accuracy of SS in detecting clinical significant portal hypertension (CSPH) and severe portal hypertension.

METHOD

Nine studies were included from thorough literature research and selection processes. A random model was used to analyze the correlation between HVPG and SS. We adopted the bivariate mixed effects model to assess the diagnostic performance.

RESULTS

Regarding to correlation between SS and HVPG, the summary correlation coefficient was 0.72 (95% confidence interval [CI], 0.63-0.80). In detection of CSPH, the sensitivity, specificity, AUC and DOR were: 0.88 (0.70-0.96), 0.84 (0.72-0.92), 0.92 (0.89-0.94) and 38 (17-84) for CSPH, respectively; and 0.92 (0.82-0.96), 0.79 (0.72-0.85), 0.87 (0.84-0.90) and 41 (17-100) for severe portal hypertension, respectively.

CONCLUSION

Correlation between SS and HVPG was good. Although SS showed good sensitivity and specificity, the different cut-off values and techniques among studies might limit the impact of our results on clinical practice. Therefore, more high-quality prospective studies are required to evaluate the role of SS in predicting portal hypertension.

Non-invasive evaluation of portal hypertension using ultrasound elastography

Portal hypertension (PH) leads to serious complications, such as bleeding from gastroesophageal varices, ascites and portosystemic encephalopathy in patients with chronic liver disease (CLD). Gold standard methods for assessing PH and its complications include the measurement of hepatic venous pressure gradient and endoscopy; however, these are invasive, expensive and not available at all centres. Therefore, non-invasive alternatives have been the subject of extensive investigation over the last 20years. The present review focuses on the role of ultrasound elastography - a novel group of non-invasive techniques used to measure stiffness in target organs. In the context of CLD these methods are used to identify the presence of PH, its severity, and the risk of PH-related complications. The rationale, accumulated evidence, advantages and limitations of liver and spleen stiffness measurements evaluated by different ultrasound elastography techniques in patients with advanced CLD is discussed. Recent data regarding the use of ultrasound elastography techniques in patients with non-cirrhotic forms of PH are also described.

Acoustic radiation force impulse quantification of spleen elasticity for assessing liver fibrosis

PURPOSE

The purpose of this study is to assess the correlation between liver fibrosis and spleen stiffness measured by ARFI in patients with chronic viral hepatitis (B or C) and to explore the possible complementary role of spleen and liver ARFI in grading liver fibrosis.

METHODS

84 subjects (51 patients, 33 healthy volunteers) were enrolled. ARFI of the spleen and the liver was performed. Patients subsequently underwent liver biopsy for grading liver fibrosis according to Knodell scoring system. Multivariate logistic regression and decision tree analysis were adopted to test the relationship between spleen and liver stiffness (independent variables) and liver fibrosis (F1< vs. ≥F3). Leave-One-Out Cross-Validation was used for validating the predictive classification models. Area under the ROC curve (AUROCC) was used as accuracy metric.

RESULTS

Spleen ARFI was able to discriminate early (F1) from severe (≥F3) liver fibrosis with an optimal cut-off of 3.05 m/s: AUROCC 0.807, cross-validated AUROCC 0.614. Liver ARFI was superior to spleen ARFI, using a cut-off of 2.11 m/s: AUROCC 0.879, cross-validated AUROCC 0.672. Neither spleen nor liver ARFI was able to differentiate healthy volunteers from F1 patients. Odds ratios derived from logistic regression were 23.1 and 9.9 for liver and spleen ARFI, respectively; resulting AUROCC was 0.905 (cross-validated 0.848). A decision tree considering the sequential use of liver and spleen ARFI with cut-off of 2.14 and 3.39 m/s, respectively, resulted in AUROCC of 0.903 (cross-validated 0.7).

CONCLUSIONS

Spleen ARFI has the potential to discriminate early from severe liver fibrosis. Spleen and liver ARFI, when combined, show a better discriminative power than liver ARFI alone.

Liver and spleen transient elastography predicts portal hypertension in patients with chronic liver disease: a prospective cohort study

BACKGROUND

To assess correlation between liver or spleen stiffness measurement by transient elastography (TE) and hepatic venous pressure gradient (HVPG) in patients with chronic liver disease as well find optimal and rule in/rule out cut-offs for prognosis of clinically significant (CSPH) and severe (SPH) portal hypertension.

METHODS

In this prospective study patients with different chronic liver diseases were included. TE was performed at the same day prior to HVPG measurement. HVPG was measured using catheter tip occlusion technique. Based on HVPG, patients were categorized into groups of CSPH and SPH. Cut-off values were established by applying ROC curve analysis.

RESULTS

The study included 107 consecutive patients referred for HVPG measurement or transjugular liver biopsy. Successful spleen TE was performed in 99 of the patients. Liver and spleen TE strongly correlated with HVPG, r = 0.75 and r = 0.62, respectively. Accuracy to detect CSPH was 88.7% for liver stiffness of 17.4 kPa and 77.7% for spleen stiffness of 47.6 kPa. Accuracy to detect SPH was 83.1% for liver stiffness of 20.6 kPa and 77.7 % for spleen stiffness of 50.7 kPa. Liver stiffness <11.4 kPa could rule out CSPH with 55.2% specificity and >21.9 kPa rule in CSPH with 74.4% sensitivity. Liver stiffness <12.1 kPa could rule out SPH with 50.0% specificity and >35 kPa rule in SPH with 58.2% sensitivity.

CONCLUSIONS

Liver and spleen stiffness correlate with HVPG and could be used to predict CSPH or SPH. Spleen elastography was not superior to liver elastography in predicting portal hypertension.

Ultrasound-based elastography for the diagnosis of portal hypertension in cirrhotics

Progressive fibrosis is encountered in almost all chronic liver diseases. Its clinical signs are diagnostic in advanced cirrhosis, but compensated liver cirrhosis is harder to diagnose. Liver biopsy is still considered the reference method for staging the severity of fibrosis, but due to its drawbacks (inter and intra-observer variability, sampling errors, unequal distribution of fibrosis in the liver, and risk of complications and even death), non-invasive methods were developed to assess fibrosis (serologic and elastographic). Elastographic methods can be ultrasound-based or magnetic resonance imaging-based. All ultrasound-based elastographic methods are valuable for the early diagnosis of cirrhosis, especially transient elastography (TE) and acoustic radiation force impulse (ARFI) elastography, which have similar sensitivities and specificities, although ARFI has better feasibility. TE is a promising method for predicting portal hypertension in cirrhotic patients, but it cannot replace upper digestive endoscopy. The diagnostic accuracy of using ARFI in the liver to predict portal hypertension in cirrhotic patients is debatable, with controversial results in published studies. The accuracy of ARFI elastography may be significantly increased if spleen stiffness is assessed, either alone or in combination with liver stiffness and other parameters. Two-dimensional shear-wave elastography, the ElastPQ technique and strain elastography all need to be evaluated as predictors of portal hypertension.

Normal values of spleen stiffness in healthy children assessed by acoustic radiation force impulse imaging (ARFI): comparison between two ultrasound transducers

BACKGROUND

Portal hypertension, a major complication of hepatic fibrosis, can affect the stiffness of the spleen.

OBJECTIVE

To suggest normal values of spleen stiffness determined by acoustic radiation force impulse imaging in healthy children and to compare measurements using two different US probes.

MATERIALS AND METHODS

In a prospective study, 60 healthy children between 1 day and 14 years of age were assigned to four age groups with 15 children in each. Measurements were performed using two transducers (convex 4C1 and linear 9L4), and 10 measurements were obtained in each child, 5 with each probe.

RESULTS

The mean splenic shear wave velocities were 2.17 m/s (SD 0.35, 95% CI 2.08-2.26) with the 4C1 probe and 2.15 m/s (SD 0.23, 95% CI 2.09-2.21) with the 9L4 probe (not significant).

CONCLUSION

We found normal values for spleen stiffness with no difference in the mean values obtained using two types of US transducers, but with higher variability using a convex compared to a linear transducer.

A novel model to predict esophageal varices in patients with compensated cirrhosis using acoustic radiation force impulse elastography

Background & Aims

Few noninvasive methods can accurately identify esophageal varices (EVs) in patients with compensated cirrhosis. We developed and validated a novel, acoustic radiation force impulse (ARFI) elastography-based prediction model for high-risk EVs (HEVs) in patients with compensated cirrhosis.

Methods

A total of 143 patients with compensated cirrhosis between February, 2010 and February, 2013 (training set) and 148 between June, 2010 and May, 2013 (validation set) who underwent ARFI elastography and endoscopy were prospectively recruited. Independent predictors of HEVs were used to construct a prediction model.

Results

Based on multivariate analysis, we developed two new statistical models, a varices risk score and ARFI-spleen diameter-to-platelet ratio score (ASPS), the latter of which was calculated as ARFI velocity × spleen diameter/platelet count. The area under receiver operating characteristic curve (AUROC) of the varices risk score and ASPS to predict HEVs were 0.935 (95% confidence interval [CI] 0.882–0.970) and 0.946 (95% CI 0.895–0.977), respectively. When ASPS, a simpler model with a higher AUROC, was applied in the validation set, acceptable diagnostic accuracy for HEVs was observed (AUROC = 0.814 [95% CI 0.743–0.885]). To detect HEVs, a negative predictive value of 98.3% was achieved at ASPS <2.83, whereas a positive predictive value of 100% was achieved at ASPS >5.28.

Conclusions

ASPS, a novel noninvasive ARFI-based prediction model, can accurately identify HEVs in patients with compensated cirrhosis. ASPS <2.83 may safely rule out the presence of HEVs, whereas patients with ASPS >5.28 should be considered for endoscopic examinations or appropriate prophylactic treatment.

Spleen stiffness measurement by transient elastography to diagnose portal hypertension in children

BACKGROUND

The development of esophageal varices is a late complication of chronic liver disease (LD) in children. The diagnosis is presently limited to invasive procedures such as endoscopy. Noninvasive tools to diagnose the presence and degree of esophageal varices would alter management decisions and support indications for invasive procedures in affected children. The aim of the study was to test the feasibility of spleen stiffness measurement (SSM) by transient elastography (TE; FibroScan) in children and compare data on its diagnostic use with established markers of liver fibrosis and parameters of portal hypertension.

METHODS

A total of 99 children (62 with chronic LD, 6 after liver transplantation, 31 controls) underwent SSM by TE. Fibrotest was determined in 37 children, 45 children had an additional liver stiffness measurement, and 19 underwent upper endoscopy.

RESULTS

SSM by FibroScan is feasible. Spleen size significantly determined success rate (90.5% in patients with splenomegaly vs 70.2% in patients without, P = 0.02). Spleen stiffness was significantly higher in patients with splenomegaly (62.96 vs 18.4 kPa, P < 0.001), in patients with varices (75 vs 24 kPa, P < 0.01), and in patients with a history of variceal hemorrhage (75 vs 50.25 kPa, P < 0.05). Variceal hemorrhage did not occur in patients with SSM results <60 kPa. Spleen stiffness decreased after liver transplantation, but remained elevated compared with controls (27.5 vs 16.3 kPa). Liver stiffness measurements and Fibrotest did not reflect the presence or degree of esophageal varices.

CONCLUSIONS

SSM by TE is feasible in children and the results reflect the degree and occurrence of complications. A prospective follow-up study with larger patient numbers and performance of screening endoscopies appears justified and desirable.

Invasive and non-invasive techniques for detecting portal hypertension and predicting variceal bleeding in cirrhosis: a review

Portal hypertension is a severe syndrome that may derive from pre-sinusoidal, sinusoidal, and post-sinusoidal causes. As a consequence, several complications (i.e. ascites, oesophageal varices) may develop. In sinusoidal portal hypertension, hepatic venous pressure gradient (HVPG) is a reliable method for defining the grade of portal pressure, establishing the effectiveness of the treatment, and predicting the occurrence of complications; however, some questions exist regarding its ability to discriminate bleeding from non-bleeding varices in cirrhotic patients. Other imaging techniques (transient elastography, endoscopy, endosonography, and duplex Doppler sonography) for assessing causes and complications of portal hypertensive syndrome are available and may be valuable for the management of these patients. In this review, we evaluate invasive and non-invasive techniques currently employed to obtain a clinical prediction of deadly complications, such as variceal bleeding in patients affected by sinusoidal portal hypertension, in order to create a diagnostic algorithm to manage them. Again, HVPG appears to be the reference standard to evaluate portal hypertension and monitor the response to treatment, but its ability to predict several complications and support management decisions might be further improved through the diagnostic combination with other imaging techniques.

The role of ultrasound elastographic techniques in chronic liver disease: current status and future perspectives

This review illustrates the state of the art clinical applications and the future perspectives of ultrasound elastographic methods for the evaluation of chronic liver diseases, including the most widely used and validated technique, transient elastography, followed by shear wave elastography and strain imaging elastography. Liver ultrasound elastography allows the non-invasive evaluation of liver stiffness, providing information regarding the stage of fibrosis, comparable to liver biopsy which is still considered the gold standard; in this way, it can help physicians in managing patients, including the decision as to when to start antiviral treatment. The characterization of focal liver lesions and the prognostic role of the elastographic technique in the prediction of complications of cirrhosis are still under investigation.

Age-related changes in liver, kidney, and spleen stiffness in healthy children measured with acoustic radiation force impulse imaging

OBJECTIVES

To evaluate the feasibility and age-related changes of shear wave velocity (SWV) in normal livers, kidneys, and spleens of children using acoustic radiation force impulse (ARFI) imaging.

MATERIALS AND METHODS

Healthy pediatric volunteers prospectively underwent abdominal ultrasonography and ARFI. The subjects were divided into three groups according to age: group 1: <5 years old; group 2: 5-10 years old; and group 3: >10 years old. The SWV was measured using a 4-9 MHz linear probe for group 1 and a 1-4 MHz convex probe for groups 2 and 3. Three valid SWV measurements were acquired for each organ.

RESULTS

Two hundred and two children (92 male, 110 female) with an average age of 8.1 years (± 4.7) were included in this study and had a successful measurement rate of 97% (196/202). The mean SWVs were 1.12 m/s for the liver, 2.19 m/s for the right kidney, 2.33 m/s for the left kidney, and 2.25 m/s for the spleen. The SWVs for the right and left kidneys, and the spleen showed age-related changes in all children (p<0.001). And the SWVs for the kidneys increased with age in group 1, and those for the liver changed with age in group 3.

CONCLUSIONS

ARFI measurements are feasible for solid abdominal organs in children using high or low frequency probes. The mean ARFI SWV for the kidneys increased according to age in children less than 5 years of age and in the liver, it changed with age in children over 10.

Can ARFI elastography predict the presence of significant esophageal varices in newly diagnosed cirrhotic patients?

AIM

To establish an algorithm which includes the liver stiffness (LS) and/or spleen stiffness (SS) assessed by ARFI for the prediction of significant esophageal varices-EV (at least grade 2).

MATERIAL AND METHODS

Our study included 145 newly diagnosed cirrhotic patients admitted in our Department between September 2009-August 2011. 62 patients (42.7%) had significant EV. We performed 10 ARFI measurements in each patient, both in the liver and in the spleen; median values were calculated, expressed in meters/second. In 24 consecutive newly diagnosed cirrhotic patients admitted between September 2011-December 2011, we prospectively analyzed the value of the new score for predicting significant EV.

RESULTS

The LS and SS assessed by ARFI elastography, and the percentage of patients with ascites were stastically significant higher in patients with significant EV as compared with those without EV or grade 1 EV. By multiple regression analysis we obtained the following formula for predicting significant EV: prediction of significant EV (Pred EV(2-3)) score: -0.572 + 0.041 x LS (m/s) + 0.122 x SS (m/s) + 0.325 x ascites (1-absent, 2-present). The best Pred EV(2-3) cut-off value for predicting significant EV was > 0.395 (AUROC = 0.721, accuracy = 69.6%). The accuracy in the group of patients in which the value of this score was prospectively analyzed was similar with that obtained in the first cohort of patients (70.8 vs. 69.6%). In conclusion, the proposed Pred EV(2-3) score had a enough good value for predicting significant EV.