Hepatic vein transit times using a microbubble agent can predict disease severity non-invasively in patients with hepatitis C

Demonstration of Hepatic Vein Abnormalities Using Contrast-Enhanced Sonography in Liver Diseases

Contrast-enhanced US (CEUS) is now widely used to observe the hemodynamics of the liver. The CEUS diagnosis mainly consists of evaluating hepatic artery and portal vein flow changes in liver diseases, but it has not been widely used for the diagnosis of hepatic venous (HV) abnormalities in the clinical setting. For this background, this review tried to reconsider this problem. In short, observing HV CEUS findings, especially HV transit time, serves to largely narrow the differential diagnosis and increase the diagnostic confidence of the CEUS. However, diagnosing HV CEUS diagnosis in a wide range of liver diseases requires understanding of vascular anatomy of the upper abdomen and vascular structure of each disease. Additionally, interpreting CEUS findings of HCC should be prudent, because its drainage vessels change according to the histological progression, from the HV to the portal vein. Thus, the most important way of making use of the CEUS information is interpreting it in conjunction with the clinical data.

Vasomics of the liver

Chronic liver disease is a cluster of disorders associated with complex haemodynamic alterations, which is characterised by structural and functional disruptions of the intrahepatic and extrahepatic vasculature. 'Vasomics' is an emerging omics discipline that comprehensively analyses and models the vascular system by integrating pathophysiology of disease, biomechanics, medical imaging, computational science and artificial intelligence. Vasomics is further typified by its multidimensional, multiscale and high-throughput nature, which depends on the rapid and robust extraction of well-defined vascular phenotypes with clear clinical and/or biological interpretability. By leveraging multimodality medical imaging techniques, vascular functional assessments, pathological image evaluation, and related computational methods, integrated vasomics provides a deeper understanding of the associations between the vascular system and disease. This in turn reveals the crucial role of the vascular system in disease occurrence, progression and treatment responses, thereby supporting precision medicine approaches. Pathological vascular features have already demonstrated their key role in different clinical scenarios. Despite this, vasomics is yet to be widely recognised. Therefore, we furnished a comprehensive definition of vasomics providing a classification of existing hepatic vascular phenotypes into the following categories: anatomical, biomechanical, biochemical, pathophysiological and composite.

Value of Spleen Dynamic Contrast-enhanced Ultrasound Parameters in Predicting Hepatic Vein Pressure Gradient for Patients With Liver Cirrhosis

GOALS

To explore dynamic contrast-enhanced ultrasound (CEUS) parameters in predicting hepatic vein pressure gradient (HVPG) for patients with liver cirrhosis (LC).

BACKGROUND

Noninvasive diagnosis of HVPG remains a challenge.

STUDY

This prospective study included patients with LC undergoing hepatic vein catheterization and pressure measurement at the hospital from May 2021 to January 2023. The CEUS images (Mindray Resona R9, 1-6-MHz probe frequency; mechanical index=0.08; image depth=10 cm; focus at the lowest point of the diaphragm; dynamic range=70 dB; optimal gain; single SonoVue bolus injection) were taken for 60 seconds after injection and analyzed using VueBox. HVPG (ie, the gold standard for portal hypertension) was measured routinely by catheterization.

RESULTS

Fifty patients with LC were included in the study. The rise time (r=0.6, P<0.01), the fall time (r=0.7, P<0.01), the peak time (r=0.6, P<0.01), wash-in area under the curve (AUC) (r=0.5, P<0.01), the wash-out phase AUC (r=0.4, P<0.01) and wash-in and wash-out phase AUC (r=0.4, P<0.01) of the dynamic spleen CEUS were positively correlated with HVPG. The optimal fall time cutoff levels to predict HVPG ≥10 mm Hg and ≥12 mm Hg were 27.0 and 36.4 seconds, with the AUC being 0.958 and 0.941, respectively. The optimal area under the wash-in area cutoff level to predict HVPG ≥10 mm Hg and ≥12 mm Hg was 1,658,967.38 (a.u) and 4,244,015.90 (a.u), with the AUC being 0.865 and 0.877, respectively.

CONCLUSIONS

The fall time and wash-in AUC obtained by dynamic CEUS may help diagnose HVPG in patients with LC without requiring invasive hepatic vein catheterization.

Advancements of non‐invasive imaging technologies for the diagnosis and staging of liver fibrosis: Present and future

Liver fibrosis is a reparative response triggered by liver injury. Non‐invasive assessment and staging of liver fibrosis in patients with chronic liver disease are of paramount importance, as treatment strategies and prognoses depend significantly on the degree of fibrosis. Although liver fibrosis has traditionally been staged through invasive liver biopsy, this method is prone to sampling errors, particularly when biopsy sizes are inadequate. Consequently, there is an urgent clinical need for an alternative to biopsy, one that ensures precise, sensitive, and non‐invasive diagnosis and staging of liver fibrosis. Non‐invasive imaging assessments have assumed a pivotal role in clinical practice, enjoying growing popularity and acceptance due to their potential for diagnosing, staging, and monitoring liver fibrosis. In this comprehensive review, we first delved into the current landscape of non‐invasive imaging technologies, assessing their accuracy and the transformative impact they have had on the diagnosis and management of liver fibrosis in both clinical practice and animal models. Additionally, we provided an in‐depth exploration of recent advancements in ultrasound imaging, computed tomography imaging, magnetic resonance imaging, nuclear medicine imaging, radiomics, and artificial intelligence within the field of liver fibrosis research. We summarized the key concepts, advantages, limitations, and diagnostic performance of each technique. Finally, we discussed the challenges associated with clinical implementation and offer our perspective on advancing the field, hoping to provide alternative directions for the future research.

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.

Application of ultrasound for the diagnosis of cirrhosis/portal hypertension

With advances in technologic approaches in patients with cirrhosis, including the improvement of management, a simple, one-step approach for advanced fibrotic state of the liver is clinically useful. Although refining the diagnosis of cirrhosis to reflect disease heterogeneity is essential, current diagnostic tests have not kept pace with the progression of this new paradigm. There are unmet needs in primary care centers with respect to patients with cirrhosis. Liver biopsy and measurement of hepatic venous pressure gradient in patients with cirrhosis are the gold standards for the estimation of hepatic fibrosis, and they have diagnostic and prognostic value. However, both approaches are invasive and cannot be used repeatedly in clinical practice. Ultrasonography (US) is safe, easy to perform, inexpensive, and yields numerical and accurate results. Conventionally, the size of the liver and spleen, bluntness of the liver edge, nodularity of the liver surface, and coarseness of the liver parenchyma have been known as useful parameters for hepatic fibrosis or portal hypertension (PHT) in chronic liver disease. Additionally, some functional US indices including Doppler and CEUS-based examination have been suggested as promising markers for diagnosing cirrhosis and PHT. Identification of the reproducibility and long-term prognostic value through further investigations can demonstrate the clinical usefulness of functional US indices, which are characterized as quantitative parameters for hepatic fibrosis and PHT.

Contrast-Enhanced Ultrasonography-Based Hepatic Perfusion for Early Prediction of Prognosis in Acute Liver Failure

BACKGROUND AND AIMS

Acute liver failure (ALF) is a rare but dramatic clinical syndrome characterized by massive hepatic necrosis leading to multiorgan failure. It is difficult to predict the outcomes in patients with ALF using existing prognostic models. We aimed to analyze hepatic perfusion using contrast-enhanced ultrasound and Doppler ultrasound in patients with ALF and investigate its utility as a prognostic biomarker.

APPROACH AND RESULTS

In this prospective observational study, 208 patients with acute liver injury/ALF were enrolled from 2015 to 2019. We evaluated 50 consecutive patients with ALF with Doppler ultrasound and contrast-enhanced ultrasound performed on admission. The cases were divided into the following two groups: survivors (recovered without surgical intervention) and nonsurvivors (died of ALF or underwent liver transplantation). The time to peak and peak intensity of hepatic artery, portal vein, hepatic vein, and liver parenchyma were calculated using the time-intensity curve analysis. The hepatic artery (HA) resistive index was calculated using the fast Fourier transform analysis of Doppler ultrasound. The time interval (TI) between the time to peak of HA and liver parenchyma (LP) was significantly shorter in the nonsurvivors than in the survivors (P < 0.0001). The area under the receiver operating curve values for TI (HA, LP), Japanese scoring system, HE prediction model, Model for End-Stage Liver Disease score, and King's College Hospital criteria for the prediction of poor prognosis were 0.953, 0.914, 0.861, 0.816, and 0.731, respectively. The most appropriate cutoff value of TI (HA, LP) was 6.897 seconds; the sensitivity, specificity, positive and negative predictive values were 94.4%, 90.6%, 85.0%, and 96.7%, respectively.

CONCLUSIONS

TI (HA, LP) accurately predicts the outcome in patients with ALF and may be useful in clinical decision making.

Performance of Ultrasound Techniques and the Potential of Artificial Intelligence in the Evaluation of Hepatocellular Carcinoma and Non-Alcoholic Fatty Liver Disease

Global statistics show an increasing percentage of patients that develop non-alcoholic fatty liver disease (NAFLD) and NAFLD-related hepatocellular carcinoma (HCC), even in the absence of cirrhosis. In the present review, we analyzed the diagnostic performance of ultrasonography (US) in the non-invasive evaluation of NAFLD and NAFLD-related HCC, as well as possibilities of optimizing US diagnosis with the help of artificial intelligence (AI) assistance. To date, US is the first-line examination recommended in the screening of patients with clinical suspicion of NAFLD, as it is readily available and leads to a better disease-specific surveillance. However, the conventional US presents limitations that significantly hamper its applicability in quantifying NAFLD and accurately characterizing a given focal liver lesion (FLL). Ultrasound contrast agents (UCAs) are an essential add-on to the conventional B-mode US and to the Doppler US that further empower this method, allowing the evaluation of the enhancement properties and the vascular architecture of FLLs, in comparison to the background parenchyma. The current paper also explores the new universe of AI and the various implications of deep learning algorithms in the evaluation of NAFLD and NAFLD-related HCC through US methods, concluding that it could potentially be a game changer for patient care.

Measuring Intrahepatic Vascular Changes Using Contrast-Enhanced Ultrasonography to Predict the Prognosis of Alcoholic Hepatitis Combined with Cirrhosis: A Prospective Pilot Study

Background/Aims

Acute hepatic dysfunction combined with alcoholic hepatitis (AH) in alcoholic cirrhosis is related to hepatic hypo-perfusion secondary to intrahepatic necroinflammation, neoangiogenesis, and shunt. The hepatic vein arrival time (HVAT) assessed by microbubble contrast-enhanced ultrasonography (CEUS) is closely correlated with the severity of intrahepatic changes. We investigated the usefulness of HVAT to predict short-term mortality of AH in cirrhosis.

Methods

Thirty-nine patients with alcoholic cirrhosis (27 males) and AH were prospectively enrolled. HVAT study was performed within 3 days after admission using ultrasonic contrast (SonoVue^®). The primary outcome was 12-week mortality.

Results

Twelve-week mortality developed in nine patients. HVAT was significantly different between the mortality and survival groups (9.3±2.0 seconds vs 12.6±3.5 seconds, p=0.002). The odds ratio of a shortened HVAT for 12-week mortality was 1.481 (95% confidence interval, 1.050–2.090; p=0.025). The area under the receiver operating characteristic curve of HVAT for 12-week mortality was 0.787 (p=0.010). The combination of MDF and HVAT ≥11.0 seconds resulted in an 87.5% survival rate even if the MDF score ≥32; however, HVAT <11.0 seconds was related with mortality despite a MDF score<32.

Conclusions

HVAT using microbubble CEUS could be a useful additional index to predict short-term mortality in patients with AH and cirrhosis.

The Application of Parametric Micro-Flow Imaging in the Evaluation of Liver Fibrosis

This study aims to investigate the application of parametric micro-flow imaging in the evaluation of liver fibrosis. From March 2013 to February 2014, 117 participants were recruited in this research prospectively, which includes 97 patients (who have been infected with hepatitis B virus or/and hepatitis C virus and have undergone liver biopsy) and 20 healthy volunteers. Contrast agent was injected as a bolus via the antecubital vein for the participants. Dynamic images of intercostal liver were collected and then divided into 30-second (30s) group and 10-second (10s) group. Color coding and quantitative analysis were performed, and related parameters were obtained and analyzed with the stage of liver fibrosis. The comparison of parameters between the stages of liver fibrosis was that the value of 30s slope reduced and the value of 10s slope increased with the increasing fibrosis stages. The value of 30s ratio at 5 seconds and 10s ratio at 5 seconds both increased with the increasing fibrosis stages. Receiver operating characteristic curves were obtained to evaluate the cutoff values and diagnosibility of parameters to predict F2 and higher or F3 and higher of fibrosis stages. The results show that parametric micro-flow imaging has potential value of guiding antiviral therapy for patients with viral hepatitis and evaluating the degree of improvement in liver fibrosis.

Non-invasive in vivo Imaging Grading of Liver Fibrosis

Liver fibrosis (LF), a common consequence of chronic liver diseases with various etiologies, is characterized by excessive accumulation of macromolecules, including collagen, glycoproteins and proteoglycans, in the liver. LF can result in hepatic dysfunction, cirrhosis, portal hypertension and, in some cases, hepatocellular carcinoma. As the current gold standard for diagnosing LF, liver biopsy, however, is invasive and prone to sampling errors and procedure-related complications. Therefore, developing noninvasive, precise and reproducible imaging tests for diagnosing and staging LF is of great significance. Conventional ultrasound (US), computed tomography (CT) and magnetic resonance (MR) imaging can depict morphological alterations of advanced LF, but have relatively limited capability characterizing early-stage LF. In order to optimize the diagnostic performances of noninvasive imaging techniques for LF across its entire spectrum of severity, a number of novel methods, including US elastography, CT perfusion imaging and various MR imaging-based techniques, have been established and introduced to clinical practice. In this review, we intended to summarize current noninvasive imaging techniques for LF, with special emphasis on the possible roles, advantages and limitations of the new emerging imaging modalities.

Noninvasive Assessment of Portal Hypertension in Advanced Chronic Liver Disease: An Update

The assessment of portal hypertension is a relevant step in the evaluation of newly diagnosed advanced chronic liver disease (ACLD). The current gold standard includes the invasive evaluation of hepatic venous pressure gradient (HVPG) and endoscopy. However, noninvasive or minimally invasive techniques to assess portal hypertension have been proposed and well established. In the present manuscript, we review clinical studies on the use of noninvasive or minimally invasive techniques to assess portal hypertension in ACLD patients.

Assessment of liver fibrosis by ultrasound elastography and contrast-enhanced ultrasound: a randomized prospective animal study

This study aimed to assess liver fibrosis by contrast-enhanced ultrasound (CEUS) and point shear-wave elastography (pSWE) in rabbits and compare the performance of the two techniques. Eighty rabbits were divided into experimental (n=60) and control group (n=20). In the experimental group, liver fibrosis (F1-F4) was induced by subcutaneous injection of carbon tetrachloride. CEUS and pSWE of the liver was performed for the two groups at a 4-week interval for 40 weeks. The portal vein rise time (PV-RT), time to peak (PV-TTP), mean transit time (PV-MTT) and the maximum signal intensity (PV-Imax) were analyzed with time-intensity curves (TICs). Liver stiffness value (LSV) was obtained through pSWE. Histologic examination of liver specimens of the rabbits was performed to evaluate the fibrosis stage. PV-RT, PV-TTP, PV-Imax and LSV were significantly different among five liver fibrosis stages (F0-F4) (P<0.01). PV-Imax and LSV displayed better diagnostic performance than PV-RT, PV-TTP, PV-MTT. For diagnosing≥F1 stage fibrosis, the area under the receiver operating characteristic curve (AUROC) of PV-Imax was 0.870, which was similar to that of LSV 0.874 (P=0.94). For diagnosing ≥F2, ≥F3 and ≥F4 stage fibrosis, the AUROC of PV-Imax and LSV was 0.845 vs. 0.956 (P=0.04), 0.789 vs. 0.954 (P=0.01) and 0.707 vs. 0.933 (P=0.03). Both CEUS and pSWE had the potential to be complementary imaging tools in the evaluation of liver fibrosis. The performance of pSWE may be better than CEUS.

Diagnostic Accuracy of Hepatic Vein Arrival Time Performed with Contrast-Enhanced Ultrasonography for Cirrhosis: A Systematic Review and Meta-Analysis

Background/Aims

We identified reports in the literature regarding the diagnostic accuracy of hepatic vein arrival time (HVAT) measured by contrast-enhanced ultrasonography (CEUS) to assess hepatic fibrosis in cirrhosis.

Methods

The Ovid MEDLINE, Embase, and Cochrane databases were searched for all studies published up to 23 July 2015 that evaluated liver status using CEUS and liver biopsy (LB). The QUADAS-II (quality assessment of diagnostic accuracy studies-II) was applied to assess the internal validity of the diagnostic studies. Selected studies were subjected to a meta-analysis with MetaDisc 1.4 and RevMan 5.3.

Results

A total of 12 studies including 844 patients with chronic liver disease met our inclusion criteria. The overall summary sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of the HVAT measured by CEUS for the detection of cirrhosis compared to LB were 0.83 (95% confidence interval [CI], 0.77 to 0.89), 0.75 (95% CI, 0.69 to 0.79), 3.45 (95% CI, 1.60 to 7.43), and 0.28 (95% CI, 0.10 to 0.74), respectively. The summary diagnostic odds ratio (random effects model) was 15.23 (95% CI, 3.07 to 75.47), the summary receiver operator characteristics area under the curve was 0.74 (standard error [SE]=0.14), and the index Q was 0.69 (SE=0.11).

Conclusions

Based on a systematic review, the measurement of HVAT by CEUS exhibited an increased accuracy and correlation for the detection of cirrhosis.

Evaluation of hepatic fibrosis: a review from the society of abdominal radiology disease focus panel

Hepatic fibrosis is potentially reversible; however early diagnosis is necessary for treatment in order to halt progression to cirrhosis and development of complications including portal hypertension and hepatocellular carcinoma. Morphologic signs of cirrhosis on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) alone are unreliable and are seen with more advanced disease. Newer imaging techniques to diagnose liver fibrosis are reliable and accurate, and include magnetic resonance elastography and US elastography (one-dimensional transient elastography and point shear wave elastography or acoustic radiation force impulse imaging). Research is ongoing with multiple other techniques for the noninvasive diagnosis of hepatic fibrosis, including MRI with diffusion-weighted imaging, hepatobiliary contrast enhancement, and perfusion; CT using perfusion, fractional extracellular space techniques, and dual-energy, contrast-enhanced US, texture analysis in multiple modalities, quantitative mapping, and direct molecular imaging probes. Efforts to advance the noninvasive imaging assessment of hepatic fibrosis will facilitate earlier diagnosis and improve patient monitoring with the goal of preventing the progression to cirrhosis and its complications.

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.

Washout Ratio in the Hepatic Vein Measured by Contrast-Enhanced Ultrasonography to Distinguish Between Inflammatory and Noninflammatory Hepatic Disorders in Dogs

Background

Perflubutane microbubbles, a second‐generation ultrasound contrast agent, are phagocytized by Kupffer cells. This characteristic may be useful to differentiate diffuse hepatic diseases in dogs.

Hypothesis/objectives

To determine whether the washout ratio in the hepatic vein (HV) measured by contrast‐enhanced ultrasonography (CEUS) can distinguish between inflammatory and noninflammatory hepatic disorders in dogs.

Animals

Forty‐one client‐owned dogs with hepatic disorders including 14 with hepatitis, 7 with primary hypoplasia of the portal vein (PHPV), 9 with congenital portosystemic shunt (cPSS), and 11 with other hepatopathy were enrolled. Six dogs without hepatic disease also were evaluated as healthy controls.

Methods

Dogs with hepatic disorders were prospectively included. Contrast‐enhanced ultrasonography of the HV was performed for 2 minutes. Washout ratio was defined as the attenuation rate from peak intensity to the intensity at the end of the CEUS study.

Results

Washout ratio in the hepatitis group (median, 18.0%; range, 2.0–37.0%) was significantly lower than that of the PHPV (median, 52.2%; range, 11.5–86.3%), cPSS (median, 60.0%; range, 28.6–77.4%), other hepatopathy (median, 70.5%; range, 26.6–88.4%), and normal (median, 78.0%; range, 60.7–91.7%) groups. The area under the receiver operating characteristic curve for hepatitis was 0.960, with a 95% confidence interval (CI) of 0.853–0.990. Washout ratio ≤37.1% resulted in a sensitivity of 100% (95% CI, 78.5–100%) and specificity of 85.2% (95% CI, 67.5–94.1%) for the prediction of hepatitis.

Conclusions and Clinical Importance

Washout ratio can distinguish hepatitis from the other noninflammatory disorders with high accuracy. This result might reflect impaired Kupffer cell phagocytosis in dogs with hepatitis.

Hepatic steatosis and fibrosis: Non-invasive assessment

Chronic liver disease is a major cause of morbidity and mortality worldwide and usually develops over many years, as a result of chronic inflammation and scarring, resulting in end-stage liver disease and its complications. The progression of disease is characterised by ongoing inflammation and consequent fibrosis, although hepatic steatosis is increasingly being recognised as an important pathological feature of disease, rather than being simply an innocent bystander. However, the current gold standard method of quantifying and staging liver disease, histological analysis by liver biopsy, has several limitations and can have associated morbidity and even mortality. Therefore, there is a clear need for safe and non-invasive assessment modalities to determine hepatic steatosis, inflammation and fibrosis. This review covers key mechanisms and the importance of fibrosis and steatosis in the progression of liver disease. We address non-invasive imaging and blood biomarker assessments that can be used as an alternative to information gained on liver biopsy.

Hepatic vein transit time of second-generation ultrasound contrast agent: new tool in the assessment of portal hypertension

PURPOSE

It has been demonstrated that Doppler waveform of the hepatic vein (normally triphasic) is transformed into a biphasic or monophasic waveform in cirrhotic patients. The compressive mechanism of liver tissue has been considered up till now the cause of this change. Moreover, cirrhotics show, after USCA injection, a much earlier HVTT due to intrahepatic shunts. Our aim was to prospectively evaluate the correlation between Doppler pattern of hepatic vein and HVTT of a second-generation USCA; we also correlated HVTT with the most common indexes of portal hypertension.

METHODS

We enrolled 38 participants: 33 cirrhotics and 5 healthy controls. Doppler shift signals were obtained from the right hepatic vein. To characterize the hepatic vein pattern, we used the hepatic vein waveform index (HVWI). This index becomes >1 with the appearance of the triphasic waveform. We recorded a clip from 20 s before to 2 min after a peripheral intravenous bolus injection of 2.4 ml of USCA (sulfur hexafluoride).The time employed by USCA to cross the liver from the hepatic artery and portal vein to the hepatic vein was defined as HA-HVTT and PV-HVTT, respectively.

RESULTS

Cirrhotics with low HVWI showed an earlier transit time; participants with higher HVWI had a longer transit time (p < 0.001). HVTT was earlier as MELD, Child-Pugh score and spleen diameter increased. Patients with ascites and varices of large size had significantly shorter transit times.

CONCLUSIONS

Abnormal hepatic vein Doppler waveform in cirrhotic patients could be due to intrahepatic shunts. HVTT could be useful in the non-invasive evaluation of portal hypertension.

Contrast-enhanced ultrasonography could be a non-invasive method for differentiating none or mild from severe fibrosis in patients with biopsy proven non-alcoholic fatty liver disease

OBJECTIVE

The gold standard for diagnosing fibrosis stage in non-alcoholic fatty liver disease (NAFLD) is liver biopsy. The aim of this study was to determine whether contrast-enhanced ultrasonography (CEUS) with transit time measurements could be a non-invasive alternative for differentiating none or mild from severe fibrosis in NAFLD patients. Various serum markers and clinical variables were also evaluated.

MATERIALS AND METHODS

Fifty-eight patients with NAFLD underwent CEUS prior to liver biopsy. All patients were also evaluated according to the Göteborg University Cirrhosis Index (GUCI), the AST-Platelet Ratio Index (APRI), the NAFLD fibrosis score, and the FIB-4 and BARD score.

RESULTS

The hepatic vein arrival time (HV) was shorter in patients with severe fibrosis (25.9 ± 4.8 vs 29.5 ± 4.7 s, p = 0.023), and the difference between the hepatic and portal vein (ΔHV-PV) was shorter (2.3 ± 2.8 vs 6.4 ± 2.8 s, p < 0.0001) while the difference in arrival time between the portal vein and hepatic artery (ΔPV-HA) arrival time was significantly longer (6.0 ± 2.2 vs 3.6 ± 1.6 s, p < 0.0001). The area under receiver operating characteristics curve values for HV, ΔHV-PV and ΔPV-HA to separate none or mild from severe fibrosis was 0.71, 0.83 and 0.84, respectively. The corresponding figures for GUCI, APRI, NAFLD fibrosis score, FIB-4 and BARD score were 0.93, 0.92, 0.86, 0.90 and 0.77, respectively.

CONCLUSIONS

CEUS and non-invasive scoring systems could exclude severe fibrosis in NAFLD patients.

Contrast-enhanced ultrasound and computerized tomography perfusion imaging of a liver fibrosis-early cirrhosis in dogs

BACKGROUND AND AIM

To assess liver fibrosis stages in a liver fibrosis-early cirrhosis model in dogs, the clinical efficiency of contrast-enhanced ultrasound (CEUS) and computed tomography (CT) perfusion imaging were compared.

METHODS

Hepatic vein arriving time (HVAT), hepatic artery arriving time, and hepatic artery to vein transit time (HA-VTT) were measured on CEUS. Total liver perfusion (TLP), portal vein perfusion (PVP), hepatic artery perfusion, and hepatic perfusion index (HPI) were measured on CT perfusion imaging. Histologic examination of liver specimens of the animals was performed to assess the fibrosis stage.

RESULTS

For assessment of liver fibrosis, the area under the receiver operating characteristic curve of CEUS indexes HVAT and HA-VTT were 0.865 and 0.930, respectively; the perfusion CT indexes TLP, PVP, and HPI were 0.797, 0.800, and 0.220, respectively; the serological index hyaluronic acid was 0.793. While for assessment of early cirrhosis, the area under the receiver operating characteristic curve of CEUS indexes HVAT and HA-VTT were 0.915 and 0.948, respectively; the perfusion CT indexes TLP, PVP, and HPI were 0.737, 0.765, and 0.218, respectively; the serological index hyaluronic acid was 0.627.

CONCLUSIONS

This study showed that both CEUS and CT perfusion imaging have the potential to be complementary imaging tools in the evaluation of liver fibrosis. While CEUS is the better choice and the index HA-VTT can be considered as non-invasive semi-quantitative indexes for diagnosing liver fibrosis and early cirrhosis.

Contrast-enhanced ultrasonography of the hepatic vein in normal dogs

Contrast-enhanced ultrasonography (CEUS) of the hepatic vein can assess intrahepatic hemodynamic changes and has been studied as a noninvasive method to assess the severity of portal hypertension and hepatic fibrosis in humans. However, few reports have described its usefulness in veterinary medicine. The purpose of this study was to characterize CEUS findings of the hepatic vein in normal dogs and assess the repeatability of this method both in a conscious group (n=6) and a sedated group (n=6). Sonazoid^® (0.01 ml/kg) was used as a contrast agent, and scanning of the hepatic vein was performed for 2 min. Time-intensity curves were generated from regions of interest in the hepatic vein. Four perfusion parameters were measured for quantitative analysis: hepatic vein arrival time (HVAT), time to peak (TTP), time to peak phase (TTPP) and wash-out ratio (WR). CEUS examinations were performed three times in each dog. The median (range) values of HVAT, TTP, TTPP and WR in the conscious group were 13.5 sec (9–22 sec), 12.5 sec (6–24 sec), 8 sec (6–13 sec) and 78.0% (60.7–91.7%), respectively. Median (range) values of HVAT, TTP, TTPP and WR in the sedated group were 12 sec (8–17 sec), 12.5 sec (9–17 sec), 9 sec (7–13 sec) and 84.1% (63.0–94.4%), respectively. The coefficients of variation of these parameters in the conscious and sedated groups were 7.6–29.7% and 11.8–14.8%, respectively.

Liver Function Assessment Using Parenchyma-Specific Contrast-Enhanced Ultrasonography

The aim of this study was to assess hepatic functional reserve by analyzing the hepatic parenchyma enhancement curve of parenchyma-specific contrast-enhanced ultrasonography (CEUS). Fifty-two patients with cirrhosis who underwent CEUS and indocyanine green tests (ICG) because of a focal liver lesion were enrolled. We evaluated the hemodynamic-related parameters of the time-intensity curve and compared these findings with the ICG retention rate at 15 min (ICG R15). The correlation between the time from peak to one half (s) and ICG R15 was statistically significant and was relatively proportional to the ICG R15. A cut-off value of 149 s was determined for the time from peak to one half for abnormal ICG R15 (>14). The sensitivity and specificity were 85.7% and 92.3%, respectively, for the detection of abnormal ICG R15. In conclusion, the time from peak to one half of the time-intensity curve of parenchyma-specific CEUS of the liver can be a useful parameter to predict the hepatic reserve in liver cirrhosis.

Liver and spleen stiffness and other noninvasive methods to assess portal hypertension in cirrhotic patients: a review of the literature

Portal hypertension (PH) is one of the most important causes of morbidity and mortality in patients with chronic liver disease. PH measurement is crucial to stage and predict the clinical outcome of liver cirrhosis. Measurement of hepatic vein pressure gradient is considered the gold standard for assessment of the degree of PH; however, it is an invasive method and has not been used widely. Thus, noninvasive methods have been proposed recently. We critically evaluated serum markers, abdominal ultrasonography, and particularly liver and spleen stiffness measurement, which represent the more promising methods to stage PH degree and to assess the presence/absence of esophageal varices (EV). A literature search was carried out on MEDLINE, EMBASE, Web of Science, and Scopus for articles and abstracts. The search terms used included 'liver cirrhosis', 'portal hypertension', 'liver stiffness', 'spleen stiffness', 'ultrasonography', and 'portal hypertension serum biomarker'. The articles cited were selected on the basis of their relevance to the objective of the review. The results of available studies indicate that individually, these methods have a mild accuracy in predicting the presence of EV, and thus they cannot substitute endoscopy to predict EV. When these tests were used in combination, their accuracy increased. In addition to the PH staging, several serum markers and spleen stiffness measurement can predict the clinical outcome of liver cirrhosis with a good accuracy, comparable to that of hepatic vein pressure gradient. In the future, noninvasive methods could be used to select patients requiring further investigations to identify the best tailored clinical management.

Prediction of liver cirrhosis, using diagnostic imaging tools

Early diagnosis of liver cirrhosis is important. Ultrasound-guided liver biopsy is the gold standard for diagnosis of liver cirrhosis. However, its invasiveness and sampling bias limit the applicability of the method. Basic imaging for the diagnosis of liver cirrhosis has developed over the last few decades, enabling early detection of morphological changes of the liver by ultrasonography (US), computed tomography, and magnetic resonance imaging (MRI). They are also accurate diagnostic methods for advanced liver cirrhosis, for which early diagnosis is difficult. There are a number of ways to compensate for this difficulty, including texture analysis to more closely identify the homogeneity of hepatic parenchyma, elastography to measure the stiffness and elasticity of the liver, and perfusion studies to determine the blood flow volume, transit time, and velocity. Amongst these methods, elastography using US and MRI was found to be slightly easier, faster, and able to provide an accurate diagnosis. Early diagnosis of liver cirrhosis using MRI or US elastography is therefore a realistic alternative, but further research is still needed.

Contrast-enhanced ultrasound for quantitative assessment of portal pressure in canine liver fibrosis

AIM: To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound (CEUS) in a canine model.

METHODS: Liver fibrosis was established in adult canines (Beagles; n = 14) by subcutaneous injection of carbon tetrachloride (CCl₄). CEUS parameters, including the area under the time-intensity curve and intensity at portal/arterial phases (Qp/Qa and Ip/Ia, respectively), were used to quantitatively assess the blood flow ratio of the portal vein/hepatic artery at multiple time points. The free portal venous pressures (FPP) were measured by a multi-channel baroreceptor using a percutaneous approach at baseline and 8, 16, and 24 wk after CCl₄ injections in each canine. Liver biopsies were obtained at the end of 8, 16, and 24 wk from each animal, and the stage of the fibrosis was assessed according to the Metavir scoring system. A Pearson correlation test was performed to compare the FPP with Qp/Qa and Ip/Ia.

RESULTS: Pathologic examination of 42 biopsies from the 14 canines at weeks 8, 16, and 24 revealed that liver fibrosis was induced by CCl₄ and represented various stages of liver fibrosis, including F0 (n = 3), F1 (n = 12), F2 (n = 14), F3 (n = 11), and F4 (n = 2). There were significant differences in the measurements of Qp/Qa (19.85 ± 3.30 vs 10.43 ± 1.21, 9.63 ± 1.03, and 8.77 ± 0.96) and Ip/Ia (1.77 ± 0.37 vs 1.03 ± 0.12, 0.83 ± 0.10, and 0.69 ± 0.13) between control and canine fibrosis at 8, 16, and 24 wk, respectively (all P < 0.001). There were statistically significant negative correlations between FPP and Qp/Qa (r = -0.707, P < 0.001), and between FPP and Ip/Ia (r = -0.759, P < 0.001) in the canine fibrosis model. Prediction of elevated FPP based on Qp/Qa and Ip/Ia was highly sensitive, as assessed by the area under the receiver operating curve (0.866 and 0.895, respectively).

CONCLUSION: CEUS is a potential method to accurately, but non-invasively, estimate portal venous pressure through measurement of Qp/Qa and Ip/Ia parameters.

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.

The accuracy of ultrasonography for the evaluation of portal hypertension in patients with cirrhosis: a systematic review

Objective

Studies have presented conflicting results regarding the accuracy of ultrasonography (US) for diagnosing portal hypertension (PH). We sought to identify evidence in the literature regarding the accuracy of US for assessing PH in patients with liver cirrhosis.

Materials and Methods

We conducted a systematic review by searching databases, including MEDLINE, EMBASE, and the Cochrane Library, for relevant studies.

Results

A total of 14 studies met our inclusion criteria. The US indices were obtained in the portal vein (n = 9), hepatic artery (n = 6), hepatic vein (HV) (n = 4) and other vessels. Using hepatic venous pressure gradient (HVPG) as the reference, the sensitivity (Se) and specificity (Sp) of the portal venous indices were 69-88% and 67-75%, respectively. The correlation coefficients between HVPG and the portal venous indices were approximately 0.296-0.8. No studies assess the Se and Sp of the hepatic arterial indices. The correlation between HVPG and the hepatic arterial indices ranged from 0.01 to 0.83. The Se and Sp of the hepatic venous indices were 75.9-77.8% and 81.8-100%, respectively. In particular, the Se and Sp of HV arrival time for clinically significant PH were 92.7% and 86.7%, respectively. A statistically significant correlation between HVPG and the hepatic venous indices was observed (0.545-0.649).

Conclusion

Some US indices, such as HV, exhibited an increased accuracy for diagnosing PH. These indices may be useful in clinical practice for the detection of significant PH.

4Ps medicine of the fatty liver: the research model of predictive, preventive, personalized and participatory medicine-recommendations for facing obesity, fatty liver and fibrosis epidemics

Relationship between adipose tissue and fatty liver, and its possible evolution in fibrosis, is supported by clinical and research experience. Given the multifactorial pathogenesis of non-alcoholic fatty liver disease (NAFLD), treatments for various contributory risk factors have been proposed; however, there is no single validated therapy or drug association recommended for all cases which can stand alone. Mechanisms, diagnostics, prevention and treatment of obesity, fatty liver and insulin resistance are displayed along with recommendations and position points. Evidences and practice can get sustainable and cost-benefit valuable outcomes by participatory interventions. These recommendations can be enhanced by comprehensive research projects, addressed to societal issues and innovation, market appeal and industry development, cultural acceptance and sustainability. The basis of participatory medicine is a greater widespread awareness of a condition which is both a disease and an easy documented and inclusive clue for associated diseases and unhealthy lifestyle. This model is suitable for addressing prevention and useful for monitoring improvement, worsening and adherence with non-invasive imaging tools which allow targeted approaches. The latter include health psychology and nutritional and physical exercise prescription expertise disseminated by continuous medical education but, more important, by concrete curricula for training undergraduate and postgraduate students. It is possible and recommended to do it by early formal teaching of ultrasound imaging procedures and of practical lifestyle intervention strategies, including approaches aimed to healthier fashion suggestions. Guidelines and requirements of research project funding calls should be addressed also to NAFLD and allied conditions and should encompass the goal of training by research and the inclusion of participatory medicine topics. A deeper awareness of ethics of competences in health professionals and the articulation of knowledge, expertise and skills of medical doctors, dieticians, health psychologists and sport and physical exercise graduates are the necessary strategy for detectin a suboptimal health status and achieving realistically beneficial lifestyle changes. “The devil has put a penalty on all things we enjoy in life. Either we suffer in health or we suffer in soul or we get fat” (Albert Einstein); the task of medical research and intervention is to make possible to enjoy life also without things that make sufferance in health and souls and which excessively increase body fat.

Hepatic perfusion parameters of contrast-enhanced ultrasonography correlate with the severity of chronic liver disease

In the study described here, we introduced a new ratio acquired with contrast-enhanced ultrasonography (CEUS): a liver parenchyma blood supply ratio that differentiates arterial and portal phases. Our purpose was to determine whether this ratio and other liver parenchyma perfusion parameters acquired with CEUS can be correlated with the severity of chronic liver disease. Twelve patients with non-cirrhotic chronic liver disease, 35 patients with cirrhosis (child class A: n = 10; child class B: n = 13; child class C: n = 12) and 21 healthy volunteers were examined by CEUS. Time-intensity curves were drawn for regions of interest located in liver parenchyma and right kidney cortex using QLAB quantification software. The arterial and portal phases were differentiated by the time to the maximum enhancement of right kidney and liver parenchyma perfusion data acquired from the time-intensity curves: the intensity of liver parenchyma perfused by hepatic arterial flow (I(ap)), the intensity of total perfusion of liver parenchyma (I(peak)), the intensity of liver parenchyma perfused by portal venous flow (I(pp)) and the ratio of portal perfusion to total perfusion of liver parenchyma expressed by the parameters I(pp)/I(peak), I(peak), I(pp) and I(pp)/I(peak) significantly decreased in patients with cirrhosis and in patients with non-cirrhotic chronic liver disease, whereas Iap increased. The parameters I(pp), I(peak), I(pp)/I(peak) and Iap correlated with the severity of chronic liver disease (r = -0.938, p < 0.001; r = -0.790, p < 0.001; r = -0.931 p < 0.001; r = 0.31, p < 0.05). The diagnostic accuracy rates for cirrhosis expressed as areas under receiver operating characteristic curves were 0.93 for I(peak), 0.98 for I(pp), 0.98 for I(pp)/I(peak), and 0.69 for I(ap). Liver parenchyma perfusion parameters obtained by CEUS were correlated with the severity of chronic liver disease and have the potential to assess cirrhosis non-invasively.

Hepatic function and non-invasive hepatosplanchnic monitoring in patients with abdominal hypertension

A better understanding of intra-abdominal hypertension with relation to the liver is vital to the management of all forms of liver pathophysiology. Supporting good hepatic function within the critically ill patient is important not only in maintaining synthetic function, but also in avoiding the multi-organ complications of liver dysfunction. The resulting reduction in hepato-splanchnic blood flow (HSBF) observed with increasing intra-abdominal pressure has been clearly documented and seen to be exaggerated in animals with established liver disease. Unfortunately the tools required to measure this, remain difficult to apply routinely in the clinical setting and as such goal directed therapy to specifically improve the hepatosplanchnic circulation remains elusive. Given the documented effects of IAP on HSBF and the relatively high incidence of intra-abdominal hypertension and the abdominal compartment syndrome within "liver patients" as a whole, close attention to IAP and timely correction by appropriate medical or surgical means would appear to be essential.

Ultrasound in chronic liver disease

Background

With the high prevalence of diffuse liver disease there is a strong clinical need for noninvasive detection and grading of fibrosis and steatosis as well as detection of complications.

Methods

B-mode ultrasound supplemented by portal system Doppler and contrast-enhanced ultrasound are the principal techniques in the assessment of liver parenchyma and portal venous hypertension and in hepatocellular carcinoma surveillance.

Results

Fibrosis can be detected and staged with reasonable accuracy using Transient Elastography and Acoustic Radiation Force Imaging. Newer elastography techniques are emerging that are undergoing validation and may further improve accuracy. Ultrasound grading of hepatic steatosis currently is predominantly qualitative.

Conclusion

A summary of methods including B-mode, Doppler, contrast-enhanced ultrasound and various elastography techniques, and their current performance in assessing the liver, is provided.

Teaching Points

• Diffuse liver disease is becoming more prevalent and there is a strong clinical need for noninvasive detection.

• Portal hypertension can be best diagnosed by demonstrating portosystemic collateral venous flow.

• B-mode US is the principal US technique supplemented by portal system Doppler.

• B-mode US is relied upon in HCC surveillance, and CEUS is useful in the evaluation of possible HCC.

• Fibrosis can be detected and staged with reasonable accuracy using TE and ARFI.

• US detection of steatosis is currently reasonably accurate but grading of severity is of limited accuracy.

Biomarkers of liver fibrosis

Liver fibrosis is the final common pathway for almost all causes of chronic liver injury. Liver fibrosis is now known to be a dynamic process having significant potential for resolution. Therefore, fibrosis prediction is an essential part of the assessment and management of patients with chronic liver disease. As such, there is strong demand for reliable liver biomarkers that provide insight into disease etiology, diagnosis, therapy, and prognosis in lieu of more invasive approaches such as liver biopsy. Current diagnostic strategies range from use of serum biomarkers to more advanced imaging techniques including transient elastography and magnetic resonance imaging. In addition to these modalities, there are other approaches including the use of novel, but yet to be validated, biomarkers. In this chapter, we discuss the biomarkers of liver fibrosis including the use of invasive and noninvasive biomarkers and disease-specific biomarkers in various chronic liver diseases.

Can contrast-enhanced ultrasound distinguish malignant from reactive lymph nodes in patients with head and neck cancers?

The purpose of this study was to investigate the utility of contrast-enhanced ultrasound in differentiating benign from malignant cervical lymph nodes in patients with squamous cell carcinoma of the head and neck. A consecutive series of 17 patients with known head and neck malignancy scheduled for neck surgery and lymph node clearance were recruited for contrast-enhanced ultrasound evaluation. Sonographic signal intensity as a function of time, comparing features of time to peak, time to arrival and time to wash-out, was quantified. The selected node was removed surgically and submitted for histology. Contrast-enhanced ultrasound examination had 100% sensitivity and 85.7% specificity for lymph node involvement. Functional analysis revealed contrast peaks significantly earlier in the malignant nodes (mean ± standard deviation) of 24.14 ± 2.7 s compared with 29.33 ± 3.4 s (p = 0.0128). Contrast-enhanced ultrasound holds promise in the detection and characterization of metastatic nodes that would not be diagnosed as abnormal on the basis of conventional ultrasound criteria.

Noninvasive diagnosis of compensated cirrhosis using an analysis of the time-intensity curve portal vein slope gradient on contrast-enhanced ultrasonography

Purpose

We measured the slope gradients (SGs) of the vascular time–intensity curves (TICs) of the intrahepatic vessels on contrast-enhanced ultrasonography (CEUS). The aim of this study was to assess the diagnostic accuracy of the SG of each hepatic vessel, particularly the portal vein (PV), for detecting cirrhosis and to compare this method with conventional modalities.

Methods

Fifty-one preoperative patients underwent CEUS, and the TICs were plotted. The SGs of the hepatic artery, PV and hepatic vein were obtained from the linear functions between the slope of the arrival time of the contrast agent and the peak enhancement time of each vessel. The transit times and levels of biochemical markers were also measured. The patients were divided into three groups according to the Metavir score: F0/1 group (n = 14), F2/3 group (n = 21) and F4 group (n = 16).

Results

The PVSG significantly decreased in the F4 group (F0/1: 29.1 ± 2.27, F2/3: 23.1 ± 1.86, F4: 14.7 ± 2.13). The PVSG demonstrated high accuracy for diagnosing cirrhosis and was correlated with the levels of ICG-R15 and hyaluronic acid (Spearman rank correlation; ρ = −0.5691, p < 0.001 and ρ = −0.4652, p = 0.0006).

Conclusions

The PVSG has the potential to be a diagnostic marker for identifying patients with well-compensated cirrhosis.

Obliteration of gastric varices improves the arrival time of ultrasound contrast agents in hepatic artery and vein

BACKGROUND AND AIM

Liver cirrhosis (LC) is accompanied by hepatic arterializations, intrahepatic shunts, and hyperdynamic circulations. These changes shorten the arrival time (AT) of ultrasound contrast agents to the hepatic vein (HV). Whether treatment of gastric fundal varices (GVs) by balloon-occluded transvenous obliteration (B-RTO) improves the AT in LC patients was prospectively investigated.

METHODS

A total of 32 LC patients with GVs and 10 normal controls (NCs) were enrolled. This study was approved by the clinical research ethics committee. Images of hepatic artery (HA), portal vein (PV), and HV were monitored after an injection of a contrast agent using quantification software. The AT before and after B-RTO in LC patients and that in NCs were compared.

RESULTS

All GVs were treated effectively, and indocyanine green retention rate was improved (P < 0.0001). The mean values of the HA, PV, and HV ATs in the NCs were 21.9 ± 3.3, 28.2 ± 2.0, and 40.5 ± 2.1 s, respectively. Those in LC patients were 17.4 ± 4.4, 21.9 ± 5.6, and 26.3 ± 6.7, respectively, which were shorter than those in NCs (P < 0.01, P < 0.002, P < 0.0001, respectively). However, these ATs were significantly prolonged 1 week after B-RTO, with mean values of 18.7 ± 4.8, 23.8 ± 6.0, and 30.0 ± 7.2 s (P = 0.043, P < 0.01, P < 0.001).

CONCLUSION

Obliteration of GVs shifted the AT in LC patients to the normalization, raising the possibility of improvement of arterialization and intrahepatic shunt.

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.

Guidelines and good clinical practice recommendations for Contrast Enhanced Ultrasound (CEUS) in the liver - update 2012: A WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

Hepatorenal index as an accurate, simple, and effective tool in screening for steatosis

OBJECTIVE

The hepatorenal index has been reported to be a sensitive and noninvasive test to quantify steatosis, but it is cumbersome and time-consuming and requires specialized software. The aim of this study was to improve and simplify the hepatorenal index calculation and determine whether it is an effective tool for differentiating patients with steatosis from those without steatosis, thereby eliminating the need for biopsy in a large number of patients.

MATERIALS AND METHODS

One hundred one patients who had undergone ultrasound-guided percutaneous liver biopsy at our institution were selected from a patient database. Patients with renal disease, patients with liver masses, and patients whose liver and right kidney were not included on the same image were excluded. Images were acquired with high-resolution ultrasound, and the hepatorenal index was calculated using freeware based on comparison of hepatic and renal brightness.

RESULTS

Of the 101 patients, 63 had 5% or less steatosis and 38 had more than 5% steatosis. Using freeware available online from the National Institutes of Health, we calculated hepatorenal index values for all patients. Our data showed a strong correlation between the hepatorenal index and percentage of fat (r = 0.71, p < 0.0001). A hepatorenal index of 1.28 or greater had a 100% sensitivity for identifying more than 5% fat, 54% specificity, 0.57 positive predictive value, and 1.0 negative predictive value. If this method had been used prospectively to select patients for biopsy in our sample, 34% of biopsies could have been avoided.

CONCLUSION

The hepatorenal index is a simple, reliable, and cost-effective screening tool for identifying patients who should not undergo liver biopsy for evaluation of steatosis.

Hepatic vein arrival time as assessed by contrast-enhanced ultrasonography is useful for the assessment of portal hypertension in compensated cirrhosis

The measurement of the hepatic venous pressure gradient (HVPG) for the estimation of portal hypertension (PH) in cirrhosis has some limitations, including its invasiveness. Hepatic vein arrival time (HVAT), as assessed by microbubble contrast-enhanced ultrasonography (CEUS), is negatively correlated with the histological grade of liver fibrosis because of the associated hemodynamic abnormalities. Anatomical and pathophysiological changes in liver microcirculation are the initial events leading to PH. However, the direct relationship between HVAT and PH has not been evaluated. The present study measured both HVPG and HVAT in 71 consecutive patients with compensated cirrhosis and analyzed the relationship between the two parameters (i.e., the derivation set). Results were validated in 35 compensated patients with cirrhosis at another medical center (i.e., the validation set). The derivation set had HVPG and HVAT values of 11.4 ± 5.0 mmHg (mean ± standard deviation; range, 2-23) and 14.1 ± 3.4 seconds (range, 8.4-24.2), respectively; there was a statistically significant negative correlation between HVPG and HVAT (r(2) = 0.545; P < 0.001). The area under the receiver operating characteristic curve (AUROC) was 0.973 for clinically significant PH (CSPH; HVPG, ≥ 10 mmHg), and the sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios for CSPH for an HVAT cut-off value of 14 seconds were 92.7%, 86.7%, 90.5%, 89.7%, 6.95, and 0.08, respectively. In addition, a shorter HVAT was associated with worse Child-Pugh score (P < 0.001) and esophageal varices (P = 0.018). In the validation set, there was also a significant negative correlation between HVAT and HVPG (r(2) = 0.538; P < 0.001), and AUROC = 0.953 for CSPH. HVAT was significantly correlated with PH. These results indicate that measuring HVAT is useful for the noninvasive prediction of CSPH in patients with compensated cirrhosis.

Hepatic transit time analysis using contrast enhanced MRI with Gd-BOPTA: A prospective study comparing patients with liver metastases from colorectal cancer and healthy volunteers

PURPOSE

To find out if the hepatic transit time (HTT) shortening, which was already proven in patients with liver metastases by other modalities, can also be detected with MRI.

MATERIALS AND METHODS

The Patient group consisted of 20 subjects with liver metastases from colorectal cancer and the control group of 21 healthy subjects. Baseline and post contrast images were acquired before and after administration of Gd-BOPTA, using a T1-weighted bolus test sequence. Arrival times (AT) of the contrast agent for the aorta, the hepatic artery, the portal vein and one hepatic vein were determined. Based on arrival time measurements HTT were calculated.

RESULTS

All analyses showed significantly shorter HTT in patients with metastases compared with healthy volunteers (P < 0.05). There were no false positives using a threshold of 10.4 s for arterial to venous HTT. For aortal to venous and portal to venous HTT a threshold of 12.5 s and 4 s was calculated, respectively. No significant correlation between HTT and involved liver segments, overall volume of metastases or subject age was found.

CONCLUSION

We conclude that HTT measurements using contrast enhanced MRI with Gd-BOPTA can detect hemodynamic changes due to metastatic liver disease from colorectal cancer.

Assessment of inflammation and fibrosis in non-alcoholic fatty liver disease by imaging-based techniques

Non-alcoholic fatty liver disease (NALFD) is a burgeoning global health problem, and the assessment of disease severity remains a clinical challenge. Conventional imaging and clinical blood tests are frequently unable to determine disease activity (the degree of inflammatory change) and fibrotic severity, while the applicability of histological examination of liver biopsy is limited. Imaging platforms provide liver-specific structural information, while newer applications of these technologies non-invasively exploit the physical and chemical characteristics of liver tissue in health and disease. In this review, conventional and newer imaging-based techniques for the assessment of inflammation and fibrosis in NAFLD are discussed in terms of diagnostic accuracy, radio-pathological correlations, and practical considerations. In particular, recent clinical studies of ultrasound (US)-based and magnetic resonance elastography techniques are evaluated, while the potential of contrast-enhanced US and magnetic resonance spectroscopy techniques is discussed. The development and application of these techniques is starting to reduce the clinical need for liver biopsy, to produce surrogate end-points for interventional and observational clinical studies, and through this, to provide new insights into the natural history of NAFLD.

Accuracy and reliability of microbubble ultrasound measurements for the non-invasive assessment of hepatic fibrosis in chronic hepatitis C

AIM

  Contrast-enhanced ultrasound can be used to assess liver disease severity non-invasively by observing intra- and extrahepatic hemodynamic changes. Transit times are calculated to include intra- and extrahepatic components (hepatic vein transit time, HVTT) or the intrahepatic component (hepatic transit time, HTT), but these have not been compared directly. We aimed to compare diagnostic accuracy of HVTT and HTT in gauging the severity of chronic hepatitis C (CHC) and to assess inter- and intra-observer reliability.

METHODS

  Recorded ultrasound scans performed on 75 patients with biopsy-staged CHC, using the microbubble contrast agent Sonovue were analyzed.

RESULTS

  Diagnostic accuracy of HTT and HVTT for diagnosis of cirrhosis was 0.78 and 0.71 (P = 0.24). Diagnostic accuracy of HTT and HVTT for diagnosis of fibrosis stage >2 was 0.76 and 0.72 (P = 0.23). Negative predictive value for cirrhosis using this cut-off was high for both techniques (HVTT, 88%; HTT, 92%), suggesting utility for exclusion of cirrhosis. Inter-observer reliability for HTT and HVTT were 0.92 and 0.94, respectively. Intra-observer reliability for HTT and HVTT were 0.98 and 0.99.

CONCLUSION

  In this cohort, reliability exceeded 90% while diagnostic accuracy was in keeping with previous studies of microbubble transit time analysis. Despite higher numerical diagnostic accuracy for HTT, no significant difference was demonstrated between the techniques, suggesting that both methods can be used reliably.

Does hepatic vein transit time performed with contrast-enhanced ultrasound predict the severity of hepatic fibrosis?

Previously published data suggest a hepatic vein transit time (HVTT) threshold of more than 24 s can distinguish mild to moderate from advanced fibrosis. In this study, we attempted to validate HVTT as a noninvasive index of hepatic fibrosis. Patients were scanned using real-time, pulse-inversion mode following bolus injections of the contrast agent Definity. HVTT was correlated with the degree of fibrosis obtained from contemporaneous liver biopsy. The study population included 40 patients with chronic liver disease and five healthy volunteers. Mean HVTT correlated with histologic grade as follows: absence/minimal fibrosis (n = 18), 25.6 ± 11.8 s; moderate fibrosis (n = 17), 21.5 ± 5.9 s; and severe fibrosis (n = 8), 20.9 ± 5.5 s, (p = .615). Poor sensitivity (57%) and specificity (43%) prevent validation of the previously published HVTT threshold as a surrogate marker of hepatic fibrosis. Further work investigating the different interaction of Definity, SonoVue and Levovist with the reticulo-endothelial system may help explain the discrepant results reported here.