[Quantitative evaluation of Gd-EOB-DTPA uptake in phantom study for liver MRI]

Direct-Acting Antiviral Agents Reduce the Risk of Malignant Transformation of Hepatobiliary Phase-Hypointense Nodule without Arterial Phase Hyperenhancement to Hepatocellular Carcinoma on Gd-EOB-DPTA-Enhanced Imaging in the Hepatitis C Virus-Infected Liver

BACKGROUND AND AIMS

Hepatobiliary phase-hypointense nodules without arterial phase hyperenhancement (HHNs without APHE) on gadolinium-ethoxybenzyl-diethylenetriamine-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) are considered to be dysplastic nodules or early hepatocellular carcinoma (HCC) and have high risk of undergoing malignant transformation and progression to hypervascular HCC. The aim of this study was to evaluate the clinical outcome of HHNs without APHE diagnosed by Gd-EOB-DTPA-enhanced MRI before the eradication of HCV by direct-acting antiviral agents (DAAs).

METHODS

We retrospectively investigated 221 consecutive patients with HCV infection who were treated with DAAs. Thirty patients with 65 HHNs without APHE were enrolled in a sustained virologic response (SVR) cohort and 22 with 43 HHNs without APHE who did not receive DAAs or had failed HCV eradication therapy were enrolled in a non-SVR cohort. Fifty-seven percent of patients in the SVR group and 64% of those in the non-SVR group had a history of HCC. The primary endpoint of this study was the development of hypervascular HCC from HHNs without APHE detected on imaging. The cumulative incidence and relative risk of progression to hypervascular HCC in relation to clinical characteristics were compared between the two cohorts.

RESULTS

The 2-year cumulative incidence of progression to hypervascular HCC was 8.5 and 21.9% in the SVR and non-SVR cohorts, respectively. There was a significant reduction in progression of HHNs without APHE to HCC after the eradication of HCV (p = 0.022, log-rank test). Multivariate Cox regression analysis identified hyperintensity on T2-weighted images (relative risk 14.699, p < 0.001) and achieving SVR (relative risk 0.290, p = 0.043) as independent factors associated with the risk of HCC. During follow-up, 6 (9.2%) of the HHNs without APHE in the SVR cohort became undetectable on hepatocyte-phase images.

CONCLUSIONS

Eradication of HCV by DAAs could reduce the hypervascularization rate of HHNs without APHE, and some of these nodules disappeared.

Gadoxetic acid-enhanced magnetic resonance imaging reflects co-activation of β-catenin and hepatocyte nuclear factor 4α in hepatocellular carcinoma

AIM

The aim of this study is to clarify the correlation of the co-activation of β-catenin and hepatocyte nuclear factor (HNF)4α with the findings of gadoxetic acid-enhanced magnetic resonance imaging (MRI), organic anion transporting polypeptide (OATP)1B3 expression, and histological findings in hepatocellular carcinoma (HCC).

METHODS

One hundred and ninety-six HCCs surgically resected from 174 patients were enrolled in this study. The HCCs were classified into four groups by immunohistochemical expression of β-catenin, glutamine synthetase (GS), and HNF4α: (i) β-catenin/GS (positive [+]) HNF4α (+); (ii) β-catenin/GS (+) HNF4α (negative [-]); (iii) β-catenin/GS (-) HNF4α (+); and (iv) β-catenin/GS (-) HNF4α (-). We compared the four groups in terms of the enhancement ratio on the hepatobiliary phase of gadoxetic acid-enhanced MRI, immunohistochemical organic anion transporter polypeptide (OATP)1B3 (a main uptake transporter of gadoxetic acid) expression and histological features, overall survival, and no recurrence survival. The Kruskal-Wallis test, Steel-Dwass multiple comparisons test, Fisher's exact test, and log-rank (Mantel-Cox) test were used for statistical analyses.

RESULTS

Enhancement ratio on gadoxetic acid-enhanced MRI in HCC with β-catenin/GS (+) HNF4α (+) was significantly higher than those of the other three groups (P < 0.001). The OATP1B3 grade was also significantly higher in HCC with β-catenin/GS (+) HNF4α (+) (P < 0.001). Hepatocellular carcinoma with β-catenin/GS (+) HNF4α (+) showed the highest differentiation grade as compared to the other groups (P < 0.004). There were no significant differences in portal vein invasion, macroscopic growth pattern, or prognosis analyses between the four groups.

CONCLUSION

Co-activation of β-catenin and HNF4α would promote OATP1B3 expression, and consequently higher enhancement ratio on gadoxetic acid-enhanced MRI and higher differentiation grade in HCC.

Intrahepatic periportal high intensity on hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI: imaging findings and prevalence in various hepatobiliary diseases

PURPOSE

To reveal the incidence and degree of intrahepatic periportal high intensity (PHI) on hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI (EOB-MRI) in patients with or without various hepatobiliary diseases.

MATERIALS AND METHODS

Patients with normal liver (N = 256) and those with hepatic disorder (N = 857) who underwent EOB-MRI were the subjects in this study. Incidence of PHI was evaluated among the patients with normal liver and those with hepatic disorder. Degree of PHI was categorized into four grades and compared among the various hepatic diseases. Enhancement ratios (ER) of the PHI area, background liver with PHI, and background liver in control cases without PHI were evaluated.

RESULTS

PHI was observed in 2.7 % of the patients with hepatic disorder. No PHI was observed in the patients with normal liver. The incidence rates of PHI among various hepatobiliary diseases were as follows; liver cirrhosis 3.1 %, chronic hepatitis 1.0 %, primary biliary cirrhosis 12.5 %, idiopathic portal hypertension 33.3 %. The ER of the PHI area and background liver were 3.92 and 2.48 (p = 0.0002). There were no significant differences between the ER of the PHI area and the ER of background liver in the noncirrhotic control without PHI.

CONCLUSION

In 2.7 % of the patients with a hepatic disorder, the periportal area was saved from decrease of EOB uptake and it showed PHI.

The uptake transporter OATP8 expression decreases during multistep hepatocarcinogenesis: correlation with gadoxetic acid enhanced MR imaging

OBJECTIVES

To clarify the changes in organic anion-transporting polypeptide 8 (OATP8) expression and enhancement ratio on gadoxetic acid-enhanced MR imaging in hepatocellular nodules during multistep hepatocarcinogenesis.

METHODS

In imaging analysis, we focused on 71 surgically resected hepatocellular carcinomas (well, moderately and poorly differentiated HCCs) and 1 dysplastic nodule (DN). We examined the enhancement ratio in the hepatobiliary phase of gadoxetic acid enhanced MR imaging [(1/postcontrast T1 value-1/precontrast T1 value)/(1/precontrast T1 value)], then analysed the correlation among the enhancement ratio, tumour differentiation grade and intensity of immunohistochemical OATP8 expression. In pathological analysis, we focused on surgically resected 190 hepatocellular nodules: low-grade DNs, high-grade DNs, early HCCs, well-differentiated, moderately differentiated and poorly differentiated HCCs, including cases without gadoxetic acid-enhanced MR imaging. We evaluated the correlation between the immunohistochemical OATP8 expression and the tumour differentiation grade.

RESULTS

The enhancement ratio of HCCs decreased in accordance with the decline in tumour differentiation (P < 0.0001, R = 0.28) and with the decline of OATP8 expression (P < 0.0001, R = 0.81). The immunohistochemical OATP8 expression decreased from low-grade DNs to poorly differentiated HCCs (P < 0.0001, R = 0.15).

CONCLUSIONS

The immunohistochemical expression of OATP8 significantly decreases during multistep hepatocarcinogenesis, which may explain the decrease in enhancement ratio on gadoxetic acid-enhanced MR imaging.