Noninvasive analysis of portal pressure by contrast-enhanced sonography in patients with cirrhosis

Noninvasive Evaluation of Clinically Significant Portal Hypertension in Patients with Liver Cirrhosis: The Role of Contrast-Enhanced Ultrasound Perfusion Imaging and Elastography

BACKGROUND

Hepatic venous pressure gradient (HVPG) is the gold standard for assessing the degree of portal hypertension (PH), but it is not suitable for routine clinical use. The recently developed ultrasonography techniques, dynamic contrast-enhanced ultrasound (D-CEUS) and liver stiffness (LS), have expanded the possibilities for noninvasive evaluation.

AIMS

To investigate the usefulness of D-CEUS and elastographic parameters in assessing the presence and degree of PH.

METHODS

This is a prospective monocentric study. Patients with liver cirrhosis referred for HVPG measurements underwent hepatic Doppler ultrasound, LS measurement, and D-CEUS with a second-generation contrast agent. Pearson's correlation and a receiver operating characteristic (ROC) curve analysis were performed to assess the role of noninvasive findings in predicting clinically significant PH (CSPH) and severe PH (SPH).

RESULTS

46 consecutive patients (31 men; mean age±SD: 57±11 years) were enrolled. A significant positive correlation was noted between LS and HVPG (r = 0.809, p<0.0001) with an area under the ROC curve of 0.923. A cut-off value of 24.2 kPa best predicted CSPH with a positive predictive value of 85%. Among the D-CEUS features, the area under the ROC curves of liver parenchyma peak intensity (PI-LP) was greater than the other indices both for CSPH and SPH (1.000 and 0.981, respectively). A PI-LP under 23.3 arbitrary units indicated the presence of CSPH with a sensitivity and a specificity of 100%.

CONCLUSION

A multimodal ultrasound approach based on D-CEUS and LS might become a reliable predictor of CSPH and SPH and a useful alternative to HVPG.

Diagnostic accuracy of hepatic vein arrival time performed with contrast-enhanced ultrasonography for HCV liver cirrhosis

BACKGROUND AND STUDY AIMS

Contrast-enhanced ultrasonography (CEUS) has increased considerably the use of ultrasound for hemodynamical analyses and quantification. Bolus injection of microbubble agents is used to evaluate transit times. This study aimed to determine the diagnostic accuracy of arrival time (seconds) to the hepatic artery (HAAT), hepatic vein (HVAT), and portal vein (PVAT), based on CEUS used for the diagnosis of cirrhosis, and to correlate these arrival times with the liver stiffness and disease severity.

PATIENTS AND METHODS

This study evaluated 29 HCV cirrhotic and 19 chronic hepatitis C patients. History, clinical examination, laboratory investigations, abdominal ultrasonography, point shear-wave elastography (pSWE), and CEUS were conducted.

RESULTS

The mean liver stiffness increased significantly in cirrhotic versus chronic HCV (22.7 versus 5.1; p-value < 0.001). The mean HAAT (p-value = 0.001), PVAT (p-value = 0.002), and HVAT values (p-value: 0.001) were significantly prolonged in cirrhotic compared with chronic HCV. The HVAT cut-off point of cirrhotic patients was 18 s with a sensitivity, specificity, and accuracy of 96.6%, 63.2%, and 83.3%, respectively (area under curve: 0.801). Significant positive correlation was found between liver stiffness (kPa) and HVAT (s) (r = 0.585; p-value = 0.005). No significant correlation was detected between HVAT (s) and the severity of liver disease, as assessed by the Child or MELD scores in cirrhotic patients.

CONCLUSION

Measuring HVAT by CEUS yielded high-accuracy and correlation outcomes for cirrhosis detection. It could be a valuable noninvasive method for the diagnosis of cirrhosis.

First-Pass Arrival Interval of Ultrasound Contrast Medium in the Hepatic Artery and Portal Vein as a Marker for Assessment of Liver Transplant Recipients

BACKGROUND

This study measures the first-pass arrival times in the hepatic artery and portal vein of the transplanted liver using contrast-enhanced ultrasound (CEUS) and assess its correlation with graft performance in the early posttransplant period.

METHODS

This study evaluated 35 liver transplant recipients who underwent CEUS examination within 1 month of transplant surgery. CEUS under contrast-specific harmonic imaging mode were recorded for 60 seconds immediately after intravenous administration of microbubble ultrasound contrast medium (Sonazoid, GE Healthcare, Oslo, Norway). The recorded video clips were reviewed by 2 readers to determine the first-pass arrival times in the hepatic artery and portal vein, and the difference between the 2 was defined as the arterial-portal arrival interval (APAI). Laboratory data on the same date of CEUS examination were collected as indicators to correlate with APAI.

RESULTS

The intra- and inter-rater reliability for APAI measurement were excellent, with intraclass correlation coefficients > .95. The mean APAI was 4.5 ± 1.8 seconds (range, 2.0-10.5 seconds). The APAI was positively correlated with the serum total bilirubin level (r = 0.357, P = .035) and negatively correlated with the platelet count (r = -0.354, P = .037). At the 5 second cutoff point, a total serum bilirubin of >8 mg/dL was reported in 5 of 11 patients (45.4%) with APAI of >5 seconds and in only 3 of 24 patients (12.5%) with APAI of <5 seconds (P < .05).

CONCLUSIONS

The APAI is a quantitative marker that links the hemodynamics and the clinical status of the liver graft.

Diagnosing Portal Hypertension with Noninvasive Subharmonic Pressure Estimates from a US Contrast Agent

Background The current standard for assessing the severity of portal hypertension is the invasive acquisition of hepatic venous pressure gradient (HVPG). A noninvasive US-based technique called subharmonic-aided pressure estimation (SHAPE) could reduce risk and enable routine acquisition of these pressure estimates. Purpose To compare quantitative SHAPE to HVPG measurements to diagnose portal hypertension in participants undergoing a transjugular liver biopsy. Materials and Methods This was a prospective cross-sectional trial conducted at two hospitals between April 2015 and March 2019 (ClinicalTrials.gov identifier, NCT02489045). This trial enrolled participants who were scheduled for transjugular liver biopsy. After standard-of-care transjugular liver biopsy and HVPG pressure measurements, participants received an infusion of a US contrast agent and saline. During infusion, SHAPE data were collected from a portal vein and a hepatic vein, and the difference was compared with HVPG measurements. Correlations between data sets were determined by using the Pearson correlation coefficient, and statistical significance between groups was determined by using the Student t test. Receiver operating characteristic analysis was performed to determine the sensitivity and specificity of SHAPE. Results A total of 125 participants (mean age ± standard deviation, 59 years ± 12; 80 men) with complete data were included. Participants at increased risk for variceal hemorrhage (HVPG ≥12 mm Hg) had a higher mean SHAPE gradient compared with participants with lower HVPGs (0.79 dB ± 2.53 vs -4.95 dB ± 3.44; P < .001), which is equivalent to a sensitivity of 90% (13 of 14; 95% CI: 88, 94) and a specificity of 80% (79 of 99; 95% CI: 76, 84). The SHAPE gradient between the portal and hepatic veins was in good overall agreement with the HVPG measurements (r = 0.68). Conclusion Subharmonic-aided pressure estimation is an accurate noninvasive technique for detecting clinically significant portal hypertension. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Kiessling in this issue.

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.

Application of the Hepatic Transit Time (HTT) in Evaluation of Portal Vein Pressure in Gastroesophageal Varices Patients

OBJECTIVES

To analyze the clinical significance of using hepatic transit time (HTT) to evaluate portal vein pressure in gastroesophageal varices patients.

METHODS

For the observation group, we enrolled 50 gastroesophageal varices patients who had received esophagogastric variceal embolization in our hospital between January 2015 and February 2018. Patients without liver disease populated the control group and were recruited during the same time period. All patients underwent contrast-enhanced sonography. In the observation group, free portal pressure (FPP) was detected during esophagogastric variceal embolization with ultrasound guidance. Differences in hepatic artery-hepatic vein transit time (HA-HVTT), portal vein-hepatic vein transit time (PV-HVTT), and parenchyma-hepatic vein transit time (PA-HVTT) were compared between groups. Correlations between HA-HVTT, PV-HVTT, PA-HVTT, and FPP in the observation group were analyzed using the Pearson coefficient and linear regression analysis.

RESULTS

HA-HVTT (t = 5.078; P < .001), PV-HVTT (t = 12.163; P < .001), and PA-HVTT (t = 2.649; P = .009) within the observation group were significantly lower than those of the control group. The areas under the curve of HTT were 0.771 (HA-HVTT), 0.951 (PV-HVTT), and 0.652 (PA-HVTT), and the sensitivity and specificity of PV-HVTT at 7.99 seconds were 86.0% and 88.0%, respectively. The HA-HVTT (r = -0.799; P < .001), PV-HVTT (r = -0.554; P < .001), and PA-HVTT (r = -0.735; P < .001) negatively correlated to FPP in the observation group. Linear regression analysis showed y = -0.410x + 7.254 (HA-HVTT and FPP), y = -0.335x + 4.983 (PV-HVTT and FPP), and y = -0.566x + 4.997 (PA-HVTT and FPP) in the observation group.

CONCLUSION

Compared with the control patients, the HTT of patients with portal hypertension-esophagogastric varices was significantly shorter, and showed an inverse relationship with FPP.

Antiviral therapy effectively improves liver hemodynamics as evidenced by serum biomarker and contrast-enhanced ultrasound examinations in patients with hepatitis B cirrhosis

Background and Aims

To prospectively evaluate the effects of antiviral therapy on liver hemodynamics in patients with hepatitis B cirrhosis.

Methods

Seventy consecutive eligible HBV-related cirrhotic inpatients were enrolled in the prospective study. Fifty-two received different nucleoside analogs monotherapy and 18 denied antiviral therapy. Their liver biochemistry profiles and HBV-DNA were measured at the baseline and every 3 months. Peripheral blood vWF and sCD163, as well as liver ultrasound Doppler parameters including portal vein diameter (PVD), portal vein velocity (PVV), portal vein congestion index (PV-CI), hepatic vein damping index (HV-DI), hepatic arterial arrival time (HAAT), hepatic vein arrival time (HVAT) and intrahepatic cycle time (HV-HA), were measured at the baseline and the follow-up periods.

Results

In the antiviral group, all patients achieved complete virologic and liver biochemical responses after 3-month antiviral treatment. Furthermore, the response states were maintained till the follow-up endpoint. However, in the non-antiviral group, HBV DNA replication resulted in higher levels of ALT and AST compared to the baseline values (P < 0.05). In the antiviral group, PVD, PV-CI, HV-DI, vWF-Ag and sCD163 were all significantly reduced than the baseline values (P < 0.05), and PVV was significantly increased than the baseline value (P < 0.05).

Conclusions

Antiviral therapy could effectively suppress hepatocyte inflammation and alleviate the dysfunction of intrahepatic vascular endothelial and hepatic macrophages, which might improve hepatic hemodynamic function in HBV-related cirrhosis.

Ultrasonography for Noninvasive Assessment of Portal Hypertension

Portal hypertension is a major pathophysiology in patients with cirrhosis. Portal pressure is the gold standard to evaluate the severity of portal hypertension, and radiological intervention is the only procedure for pressure measurement. Ultrasound (US) is a simple and noninvasive imaging modality available worldwide. B-mode imaging allows broad applications for patients to detect and characterize chronic liver diseases and focal hepatic lesions. The Doppler technique offers real-time observation of blood flow with qualitative and quantitative assessments, and the application of microbubble-based contrast agents has improved the detectability of peripheral blood flow. In addition, elastography for the liver and spleen covers a wider field beyond the original purpose of fibrosis assessment. These developments enhance the practical use of US in the evaluation of portal hemodynamic abnormalities. This article reviews the recent progress of US in the assessment of portal hypertension.

Usefulness of Contrast-Enhanced Ultrasonography for Predicting Esophageal Varices in Patients with Hepatitis B Virus (HBV)-Related Cirrhosis

Background

The aim of this study was to investigate the usefulness of contrast-enhanced ultrasonography (CEUS) in predicting of esophageal varices (EV) and assessing high-risk EV in patients with hepatitis B virus (HBV)-related cirrhosis.

Material/Methods

Patients with HBV-related cirrhosis who had undergone endoscopy were prospectively recruited. Hepatic dynamic CEUS was performed. Regions of interest (ROI) were drawn on the hepatic artery, hepatic vein, portal vein, and liver parenchyma to measure the corresponding features, such as arrival times. Spearman’s correlation analysis was used to determine the relations between several dynamic CEUS features and the degree of EV. Receiver operating characteristics (ROC) curves were constructed to investigate the diagnostic performance of CEUS in assessing the presence of EV and high-risk EV.

Results

Fifty-eight patients (44 men; mean age 51.3 years) were included in this study. Of these, 18 (31.0%), 12 (20.7%), 11 (19.0%), and 17 (29.3%) of patients had grade 0, 1, 2, and 3 EV, respectively. Grade 2 and grade 3 EV were considered high-risk EV. Among the CEUS features, the area under the ROC curves of intrahepatic transit time (HV–HA, i.e., the difference between hepatic vein arrival time and hepatic artery arrival time) both for assessment of the presence of EV and high-risk EV (0.883 and 0.915, respectively) were larger than the other indices. HV–HA was negatively correlated with the grade of EV. An HV–HA of under 8.2 s indicated the presence of EV and under 7 s indicated high-risk EV.

Conclusions

Dynamic CEUS imaging is useful in assessing the presence of EV and high-risk EV in patients with HBV-related cirrhosis.

Non-invasive assessment of portal hypertension and liver fibrosis using contrast-enhanced ultrasonography

Portal hypertension and hepatic fibrosis are key pathophysiologies with major manifestations in cirrhosis. Although the degree of portal pressure and hepatic fibrosis are pivotal parameters, both are determined using invasive procedures. Ultrasound (US) is a simple and non-invasive technique that is available for use worldwide in the abdominal field. Because of its safety and easy of use, contrast-enhanced US is one of the most frequently used tools in the management of liver tumors for the detection and characterization of lesions, assessment of malignancy grade, and evaluation of therapeutic effects. This wide range of applications drives the practical use of contrast-enhanced US for evaluation of the severity of portal hypertension and hepatic fibrosis. The present article reviews the recent progress in contrast-enhanced US for the assessment of portal hypertension and hepatic fibrosis.

Severe portal hypertension in cirrhosis: evaluation of perfusion parameters with contrast-enhanced ultrasonography

OBJECTIVE

To investigate the role of contrast-enhanced ultrasonography (CEUS) and Doppler ultrasonography (DUS) in the diagnosis of severe portal hypertension (PH) in patients with liver cirrhosis (LC).

METHODS

Patients with PH scheduled to receive hepatic venous pressure gradient (HVPG) measurement were recruited for this study. Hepatic DUS and CEUS were performed successively. Several Doppler and CEUS parameters were explored for correlation with HVPG values and their association with severe PH (≥ 12 mmHg of HVPG). Comparison of the parameters between the severe and non-severe PH groups and their correlation with HVPG values was evaluated. A receiver operating characteristic (ROC) curve analysis was also performed to investigate the performance in order to diagnose severe PH.

RESULTS

Fifty-three consecutive patients were enrolled in this study. Among them, 43 patients did not have significant ascites. Compared with the non-severe PH group, portal venous velocity and intrahepatic transit time (ITT) were significantly reduced in the severe PH group (all p<0.05). Difference between inspiratory and expiratory hepatic venous damping indices (ΔHVDI), hepatic venous arrival time (HVAT) and ITT moderately correlated with HVPG (r = -0.358, -0.338, and -0.613, respectively). Areas under the curves for severe PH were 0.94 of ITT and 0.72 of HVAT, respectively (all p<0.05). ITT under 6 seconds indicated severe PH with a sensitivity of 92% and a specificity of 89%.

CONCLUSIONS

Hepatic CEUS may be more useful in estimating the HVPG value and determining the presence of severe PH compared to DUS, and ITT was the most accurate parameter to diagnose severe PH.

Contrast-enhanced sonography for quantitative assessment of portal hypertension in patients with liver cirrhosis

OBJECTIVES

The clinical utility of contrast-enhanced sonography in portal hypertension remains unclear. We explored the feasibility of using contrast-enhanced sonography for noninvasive assessment of portal venous pressure.

METHODS

Twenty healthy individuals (control group; 9 men; mean age, 46.4 years) and 18 patients with portal hypertension (15 men; mean age, 46.2 years) were enrolled in this study. The portal hypertension group included patients who underwent splenectomy and pericardial blood vessel disarticulation at our hospital from October 2010 to March 2011. One week before surgery, patients with portal hypertension underwent preoperative liver contrast-enhanced sonography. Two-dimensional, Doppler, and contrast-enhanced sonographic parameters were compared between the groups. Portal venous pressure was measured intraoperatively by portal vein puncture in the portal hypertension group, and its relationship with the other parameters was analyzed.

RESULTS

The 2-dimensional, Doppler, and contrast-enhanced sonographic parameters differed between the groups (P < .01). Portal venous pressure was inversely correlated with the area under the portal vein/hepatic artery time-intensity curve ratio (Qp/Qa), portal vein/hepatic artery strength ratio (Ip/Ia), and portal vein/hepatic artery wash-in perfusion slope ratio (βp/βa), with correlation coefficients of -0.701, -0.625, and -0.494, respectively.

CONCLUSIONS

Measurement of the liver contrast-enhanced sonographic parameters Qp/Qa, Ip/Ia, and βp/βa could be used as a new quantitative method for noninvasively assessing portal venous pressure.

Chronic liver disease: noninvasive subharmonic aided pressure estimation of hepatic venous pressure gradient

PURPOSE

To compare subharmonic aided pressure estimation (SHAPE) with pressure catheter-based measurements in human patients with chronic liver disease undergoing transjugular liver biopsy.

MATERIALS AND METHODS

This HIPAA-compliant study had U.S. Food and Drug Administration and institutional review board approval, and written informed consent was obtained from all participants. Forty-five patients completed this study between December 2010 and December 2011. A clinical ultrasonography (US) scanner was modified to obtain SHAPE data. After transjugular liver biopsy with pressure measurements as part of the standard of care, 45 patients received an infusion of a microbubble US contrast agent and saline. During infusion, SHAPE data were collected from a portal and hepatic vein and were compared with invasive measurements. Correlations between data sets were determined by using the Pearson correlation coefficient, and statistical significance between groups was determined by using the Student t test.

RESULTS

The 45 study patients included 27 men and 18 women (age range, 19-71 years; average age, 55.8 years). The SHAPE gradient between the portal and hepatic veins was in good overall agreement with the hepatic venous pressure gradient (HVPG) (R = 0.82). Patients at increased risk for variceal hemorrhage (HVPG ≥ 12 mm Hg) had a significantly higher mean subharmonic gradient than patients with lower HVPGs (1.93 dB ± 0.61 [standard deviation] vs -1.47 dB ± 0.29, P < .001), with a sensitivity of 100% and a specificity of 81%, indicating that SHAPE may be a useful tool for the diagnosis of clinically important portal hypertension.

CONCLUSION

Preliminary results show SHAPE to be an accurate noninvasive technique for estimating portal hypertension.

New developments in the treatment of hepatic tumors

The International Association of Surgeons, Gastroenterologists and Oncologists (IASGO) hosted their annual world congress under the auspices of president Masatoshi Makuuchi from Japan and the general secretary Nicolas J Lygidakis. This year the congress was held in Tokyo, and the president was Wataru Kimura of Yamagata University. It is common knowledge that a major triple disaster struck Japan in March 2011. It was thought, for a time, that the congress would not take place, but the great courage and determination of the hosts allowed the conference to continue as scheduled. This congress was one of the most interesting hosted by the IASGO, evidenced by the presence of 909 participants from 59 countries, including invited speakers from Europe, America, Africa and Asia. The congress provided an opportunity to exchange knowledge of new techniques, methods of diagnosis and therapy. The program included symposiums, video presentations, free papers and poster presentations. This manuscript highlights presentations of the newest and most original material concerning the treatment of liver tumors, especially hepatocellular carcinoma.

Simultaneous grayscale and subharmonic ultrasound imaging on a modified commercial scanner

OBJECTIVE

To demonstrate the feasibility of simultaneous dual fundamental grayscale and subharmonic imaging on a modified commercial scanner.

MOTIVATION

The ability to generate signals at half the insonation frequency is exclusive to ultrasound contrast agents (UCA). Thus, subharmonic imaging (SHI; transmitting at f(0) and receiving at f(0)/2) provides improved visualization of UCA within the vasculature via suppression of the surrounding tissue echoes. While this capability has proven useful in a variety of clinical applications, the SHI suppression of surrounding tissue landmarks (which are needed for sonographic navigation) also limits it use as a primary imaging modality. In this paper we present results using a commercial ultrasound scanner modified to allow imaging in both grayscale (f(0)=4.0 MHz) and SHI (f(0)=2.5 MHz, f(0)/2=1.25 MHz) modes in real time.

METHODS

A Logiq 9 ultrasound scanner (GE Healthcare, Milwaukee, WI) with a 4C curvilinear probe was modified to provide this capability. Four commercially available UCA (Definity, Lantheus Medical Imaging, North Billerica, MA; Optison, GE Healthcare, Princeton, NJ; SonoVue, Bracco Imaging, Milan, Italy; and Sonazoid, GE Healthcare, Oslo, Norway) were all investigated in vitro over an acoustic output range of 3.34 MPa. In vivo the subharmonic response of Sonazoid was investigated in the portal veins of four canines (open abdominal cavity) and four patients with suspected portal hypertension.

RESULTS

In vitro, the four UCA showed an average maximum subharmonic amplitude of 44.1±5.4 dB above the noise floor with a maximum subharmonic amplitude of 48.6±1.6 dB provided by Sonazoid. The average in vivo maximum signal above the noise floor from Sonazoid was 20.8±2.3 dB in canines and 33.9±5.2 dB in humans. Subharmonic amplitude as a function of acoustic output in both groups matched the S-curve behavior of the agent observed in vitro. The dual grayscale imaging provided easier sonographic navigation, while the degree of tissue suppression in SHI mode varied greatly on a case by case basis.

CONCLUSIONS

These results demonstrate the feasibility of dual grayscale and SHI on a modified commercial scanner. The ability to simultaneously visualize both imaging modes in real time should improve the applicability of SHI as a future primary clinical imaging modality.