Comparison of hepatocellular carcinoma conspicuity on hepatobiliary phase images with gadoxetate disodium vs. delayed phase images with extracellular cellular contrast agent

Current Landscape and Future Perspectives of Abbreviated MRI for Hepatocellular Carcinoma Surveillance

While ultrasound (US) is considered an important tool for hepatocellular carcinoma (HCC) surveillance, it has limited sensitivity for detecting early-stage HCC. Abbreviated MRI (AMRI) has recently gained popularity owing to better sensitivity in its detection of early-stage HCC than US, while also minimizing the time and cost in comparison to complete contrast-enhanced MRI, as AMRI includes only a few essential sequences tailored for detecting HCC. Currently, three AMRI protocols exist, namely gadoxetic acid-enhanced hepatobiliary-phase AMRI, dynamic contrast-enhanced AMRI, and non-enhanced AMRI. In this study, we discussed the rationale and technical details of AMRI techniques for achieving optimal surveillance performance. The strengths, weaknesses, and current issues of each AMRI protocol were also elucidated. Moreover, we scrutinized previously performed AMRI studies regarding clinical and technical factors. Reporting and recall strategies were discussed while considering the differences in AMRI protocols. A risk-stratified approach for the target population should be taken to maximize the benefits of AMRI and the cost-effectiveness should be considered. In the era of multiple HCC surveillance tools, patients need to be fully informed about their choices for better adherence to a surveillance program.

Gadoxetic acid-enhanced MRI for differentiating hepatic sclerosing hemangioma from malignant tumor

BACKGROUND

To investigate the imaging features of gadoxetic acid-enhanced magnetic resonance imaging (MRI) to differentiate hepatic sclerosing hemangioma from malignant tumors.

METHODS

This retrospective case-control study included 18 patients with sclerosing hemangioma and 54 patients with common hepatic malignant tumor, including hepatocellular carcinoma, metastatic adenocarcinoma, and cholangiocarcinoma, who were examined using gadoxetic acid-enhanced liver MRI from January 2008 to June 2019. Imaging features including signal intensity, tumor margins, enhancement pattern, and presence or absence of diffusion restriction were analyzed. Significant MRI features for predicting sclerosing hemangioma were identified using multivariable logistic regression analysis. Diagnostic performances of each imaging feature and combinations of significant imaging features were summarized.

RESULTS

In the multivariable analysis, irregular margins (odds ratio [OR], 10.12; 95 % confidence interval [CI], 1.27-80.94; p = 0.029), centripetal or internal nodular enhancement in the transitional phase (OR, 13.58; 95 % CI, 1.48-124.82; p = 0.021), and absence of diffusion restriction (OR, 39.20; 95 % CI, 4.82-318.49; p = 0.001) were significant imaging features for the diagnosis of sclerosing hemangioma. Presence of at least two significant imaging features had a sensitivity, specificity, and accuracy of 88.9 %, 96.3 %, and 94.4 %, respectively, for diagnosing sclerosing hemangioma.

CONCLUSION

Combinations of two or more of the significant imaging features (irregular margins, centripetal or internal nodular enhancement in the transitional phase, and absence of diffusion restriction) were effective for differentiating hepatic sclerosing hemangioma from malignant tumors using gadoxetic acid-enhanced MRI.

Imaging Modalities for Hepatocellular Carcinoma Surveillance: Expanding Horizons beyond Ultrasound

In Asian countries favoring loco-regional treatment such as surgical resection or ablation, very early-stage hepatocellular carcinoma (HCC) should be the main target for surveillance. Even though ultrasound (US) has been accepted as a primary imaging modality for HCC surveillance, its performance in detecting very early-stage HCCs is insufficient. Moreover, in more than 20% of patients at high risk for HCC, visualization of the liver on US may be limited owing to the advanced distortion and heterogeneity of the liver parenchyma. Recently revised HCC clinical guidelines allow the use of alternative surveillance tools including computed tomography or magnetic resonance imaging in patients with inadequate US exams. This paper summarizes the findings of recent studies using imaging modalities other than US as surveillance tools for HCC as well as strengths and limitations of these modalities.

Use of gadoxetate disodium in patients with chronic liver disease and its implications for liver imaging reporting and data system (LI-RADS)

Use of gadoxetate disodium, a hepatobiliary gadolinium-based agent, in patients with chronic parenchymal liver disease offers the advantage of improved sensitivity for detecting hepatocellular carcinoma (HCC). Imaging features of liver observations on gadoxetate-enhanced MRI may also serve as biomarkers of recurrence-free and overall survival following definitive treatment of HCC. A number of technical and interpretative pitfalls specific to gadoxetate exist, however, and needs to be recognized when protocoling and interpreting MRI exams with this agent. This article reviews the advantages and pitfalls of gadoxetate use in patients at risk for HCC, and the potential impact on Liver Imaging Reporting and Data System (LI-RADS) imaging feature assessment and categorization. Level of Evidence: 5 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;49:1236-1252.

Differentiation Between Hepatocellular Carcinoma Showing Hyperintensity on the Hepatobiliary Phase of Gadoxetic Acid-Enhanced MRI and Focal Nodular Hyperplasia by CT and MRI

OBJECTIVE

The purpose of this study is to identify points useful in the imaging differentiation of hepatocellular carcinoma (HCC) showing hyperintensity on the hepatobiliary phase of gadoxetic acid-enhanced MRI and focal nodular hyperplasia (FNH) and FNH-like nodules.

MATERIALS AND METHODS

We enrolled consecutive 51 pathologically diagnosed HCCs that were hyperintense on hepatobiliary phase imaging (47 patients, including 44 with cirrhosis) and 10 FNHs and eight FNH-like nodules (16 patients, including five with cirrhosis). Imaging findings of dynamic CT and gadoxetic acid-enhanced MRI were assessed by two radiologists and compared between HCC and FNH.

RESULTS

The apparent diffusion coefficient (ADC) was lower in hyperintense HCC than in FNH (p = 0.004). The enhancement patterns of hyperintense HCC and FNH at dynamic CT were significantly different (p < 0.0001), with 95.9% of HCCs and 22.2% of FNHs showing arterial phase enhancement with a washout pattern, and 4.1% of HCCs and 77.8% of FNHs showing arterial phase enhancement without a washout pattern. The frequency of coronalike enhancement was 84.3% in hyperintense HCCs versus 11.1% in FNHs (p < 0.0001). The signal distribution on the hepatobiliary phase was significantly different between hyperintense HCCs and FNHs (p = 0.0002). The frequency of a capsulelike rim was 88.2% versus 22.2%, that of a mosaic appearance was 72.5% versus 11.1%, and that of a central scar was 0% versus 55.6% in hyperintense HCCs versus FNHs (all p < 0.0001). Multivariate logistic regression analysis showed that ADC ratio (p = 0.03; odds ratio, 0.12) and enhancement pattern at dynamic CT (p = 0.04; odds ratio, 16.21) were the independent factors for differentiation between hyperintense HCC and FNH.

CONCLUSION

For the diagnosis of hyperintense HCC differentiated from FNH and FNH-like nodule, arterial phase enhancement and washout pattern at dynamic CT and decrease of ADC ratio would be important findings.