Contrast-enhanced ultrasonography using Sonazoid to evaluate changes in hepatic hemodynamics in acute liver injury

An Optimal Prognostic Model Based on Multiparameter Ultrasound for Acute-on-Chronic Liver Failure

OBJECTIVE

Acute-on-chronic liver failure (ACLF) is associated with a considerably high mortality, and accurate prognosis prediction is critical to navigate intervention decisions and improve clinical outcomes. The objective of this study was to establish a better prognostic model for ACLF based on multiparameter ultrasound in combination with clinical features.

METHODS

A total of 149 patients with ACLF were prospectively enrolled and underwent conventional ultrasound, 2-D shear wave elastography (SWE), attenuation imaging, color Doppler sonography, superb microvascular imaging and contrast-enhanced ultrasound (CEUS). Univariate and multivariate analyses were performed to identify independent ultrasound signatures for the prognosis of ACLF, which, when integrated with clinical characteristics, were used to establish a prognostic model.

RESULTS

Hepatic perfusion features of CEUS differed significantly between the poor and good prognosis groups, among which the time interval (TI) between peak portal vein (PV) velocity and liver parenchyma (LP) enhancement, TI(PV, LP), was independently associated with the prognosis of ACLF. A prediction model comprising TI(PV, LP) and the international normalized ratio was established, and the area under the curve (AUC) was 0.851, which is greater than those of the Model for End-stage Liver Disease (0.785), fall time of LP model (0.754), 2-D SWE nomogram (0.708) and TI(PV, LP) (0.352). Furthermore, the performance of the model was verified in an independent validation cohort (AUC = 0.920).

CONCLUSION

The newly developed model performs better than existing tested models; thus, it has potential as a better non-invasive model for predicting the prognosis of patients with ACLF. A future multicenter, large-sample study is required to validate the performance of this model.

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.

Recombinant human soluble thrombomodulin ameliorates acetaminophen-induced liver toxicity in mice

Recombinant human soluble thrombomodulin alpha (rhTM) has been developed as an anticoagulant with anti-inflammatory activity. Notably, acetaminophen (APAP) -induced liver disease (AILI) is caused by direct metabolite-induced hepatotoxicity as well as hepatic hyper-coagulation. To evaluate the utility of anticoagulant for the treatment of AILI, rhTM was administered in a mouse AILI model and liver damage was analyzed. AILI was induced in 8-week-old mice by intraperitoneal injection of APAP. rhTM (20 mg/kg) or placebo was injected at the same time as APAP administration. Serum alanine aminotransferase, fibrin degradation products and high-mobility group box 1 levels were significantly decreased in the rhTM-treated group compared with the control group. Furthermore, rhTM reduced the necrotic area and fibrin deposition in liver sections. rhTM suppressed the mRNA expression of heme oxygenase-1, plasminogen activator inhibitor type-1, tissue factors, and inflammatory cytokines compared with the control group. rhTM did not change the hepatic GSH content at 2 h after APAP injection, but restored them at 4 h after the insult. rhTM ameliorated liver damage in mice with AILI, probably via the improvement in liver perfusion induced by it's anticoagulant acitivity, which can lead to the suppression of secondary liver damage.

Effect of Hepatic Inflammation in Chronic Hepatitis C Infection on Fibrosis Assessment by Arrival Time Parametric Imaging

Arrival time parametric imaging (At-PI) in contrast-enhanced ultrasonography is useful for assessing liver fibrosis in chronic hepatitis C (CHC) infection. The study aimed to elucidate the effect of hepatic inflammation on At-PI efficiency. Subjects were 159 CHC patients who underwent contrast-enhanced ultrasonography immediately before liver biopsy. Ultrasound contrast agent was injected, and contrast dynamics of the S5 to S6 region of the liver and right kidney were recorded for 40 seconds. The At-PI of liver parenchyma blood flow was generated using saved video clips. Hepatic blood flow during the first 5 seconds after starting contrast injection was displayed in red and that after another 5 seconds was displayed in yellow. The ratio of red (ROR) in At-PI images of the entire liver was measured with ImageJ. Ratio of red values of livers with different activity grades (0–3) were compared for each fibrosis (F) stage as determined by biopsy. Correlations of ROR with alanine aminotransferase (ALT) levels were analyzed using a linear regression line from the distribution map. Comparison of ROR for different activity grades in each F stage revealed no significant differences. Correlation coefficient R (P value) for ALT and ROR was R = −0.0094 (P = 0.43) at F0 to F1, R = −0.186 (P = 0.21) at F2, R = −0.233 (P = 0.27) at F3, and R = 0.041 (P = 0.89) at F4, with no significant correlation between ALT and ROR in any F stage. Hepatic inflammation in CHC infection does not affect At-PI diagnostic accuracy.

Imaging Monitoring of Kupffer Cell Function and Hepatic Oxygen Saturation in Preneoplastic Changes During Cholangiocarcinogenesis

We investigated serial changes of the Kupffer cell (KC) function and hepatic oxygen saturation (sO₂) using contrast-enhanced ultrasound imaging (CEUS) and photoacoustic imaging (PAI) in preneoplastic changes during cholangiocarcinogenesis induced by obstructive cholangitis and N-nitrosodimethylamine in a mouse model. The CEUS and PAI were performed to assess Sonazoid contrast agent uptake by KC and changes in the sO₂ of liver parenchyma. An extensive bile ductular reaction, cystic dilatation, and epithelial hyperplasia with dysplastic changes were noted in the experimental group. During the preneoplastic changes, the parenchymal echogenicity on the Kupffer-phase of CEUS was continuously decreased in the experimental group, and which means that the Sonazoid phagocytosis by KC was decreased. The number of KCs was increased in the CD68 analysis, indicating functionally impaired KCs. There was a simultaneous serial decrease in sO₂ on PAI measurement of the experimental group during the preneoplastic changes. The experimental group also showed significantly higher expression of hypoxia-inducible factor-1α and vascular endothelial growth factor protein. Our study demonstrated that KC dysfunction and hypoxic environmental changes were the factors influencing preneoplastic change during cholangiocarcinogenesis, and we could non-invasively monitor these changes using CEUS and PAI.

The alterations in hepatic microcirculation and Kupffer cell activity after biliary drainage in jaundiced mice

BACKGROUND/PURPOSE

The aim of this study is to examine the effects of biliary drainage on hepatic microcirculation and Kupffer cell activity in the liver with obstructive jaundice.

METHODS

Common bile duct ligation and division was performed on C57BL/6 mice to induce obstructive jaundice. Seven or 14 days after surgery, some mice underwent biliary drainage. Three days after biliary drainage, sinusoidal perfusion, leukocyte rolling and sticking in the postsinusoidal venules, and the diameters of sinusoids containing blood flow were evaluated using intravital microscopy. Kupffer cell phagocytic activity was estimated as the ratio of Kupffer cells that phagocytosed fluorescent-labeled particles to sinusoids containing blood flow.

RESULTS

Sinusoidal perfusion after biliary drainage was significantly increased compared with that in livers with obstructive jaundice, but remained decreased compared with controls. Although the number of rolling leukocytes and sticking leukocytes was significantly decreased, the diameters of sinusoids remained reduced, associated with an increase in Kupffer cell phagocytic activity compared with controls even after biliary drainage.

CONCLUSIONS

Leukocyte-endothelial cell interaction is ameliorated but sinusoids remain narrowed due to swelling of activated Kupffer cells; this might cause deterioration of hepatic microcirculation during the early phase of biliary drainage.