Prediction of Sufficient Liver Enhancement on the Gadoxetate Disodium-enhanced Hepatobiliary Phase Imaging Using Transitional Phase Images and Albumin-bilirubin Grade

Optimization of hepatobiliary phase imaging in gadoxetic acid-enhanced magnetic resonance imaging: a narrative review

Background and Objective

Gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) is widely used in clinical practice. Its unique hepatobiliary phase (HBP) has been used to improve the detection and identification of hepatic lesions and has also been used to evaluate hepatic function and fibrosis. At the early stage of its clinical practice, the HBP was typically collected empirically with a delay of 20 minutes after intravenous administration to image the liver with sufficient enhancement for diagnosis. However, numerous methods and consensus statements for optimizing HBP acquisition have been proposed. This review details the methods and consensus statements on optimizing HBP collection.

Methods

The electronic literature search was performed using the databases PubMed, MEDLINE, Cochrane, and Embase without limit on publication period to identify published reports on optimizing HBP imaging in Gd-EOB-DTPA-enhanced MRI. Articles with low relevance to the topics were excluded.

Key Content and Findings

Recently, an increasing number of investigations suggest that collecting HBP after 20 min is too drawn-out for patients with normal liver function but is too short for patients with cirrhosis. Previous studies demonstrated that liver enhancement is closely related to liver function in Gd-EOB-DTPA-enhanced MRI. Therefore several reports have proposed various HBP delay times at different liver function levels. These delay times could be evaluated by laboratory indicators, such as prothrombin (PT) activity, total bilirubin, direct bilirubin, and the model for end-stage liver disease. Other investigations have found that the initial visualization time of the intrahepatic bile duct (IHD) in Gd-EOB-DTPA-enhanced MRI to also be related to liver enhancement and function. Therefore, initial visualization of the IHD is considered necessary for adequate HBP and has been employed in HBP acquisition in recent reports.

Conclusions

Optimizing HBP acquisition according to individual hepatic function is a good strategy and was followed in most of the investigations included in our review. Obtaining adequate HBP in the shortest possible time is the target condition in Gd-EOB-DTPA-enhanced MRI. However, a more concise and efficient HBP acquisition strategy is still expected to be developed in the future.

[Investigation of Changing Imaging Contrast Using Compressed Sensing in Gd-EOB-DTPA Hepatocyte Phase]

In recent years, gadolinium ethoxybenzyl diethylenetriamine pantaacetic acid (Gd-EOB-DTPA) has been commonly used in magnetic resonance imaging (MRI) for liver contrast studies. The purpose of this study was to investigate the effect of Hyper SENSE factor on contrast in the Gd-EOB-DTPA hepatocyte phase. The subjects were 21 patients [16 males and 5 females, aged 50-94 years (mean age 68±12years)] who underwent hepatic contrast-enhanced MRI with Gd-EOB-DTPA from March 2021 to December 2021. The contrast ratios (CRs) of liver/spleen and liver/tumor were measured when the Hyper SENSE factor was changed to 1.0, 1.4 and 1.8. As a result, there was no statistically significant difference in signal intensity and CR with the change in the Hyper SENSE factor. In this study, the acquisition time can be shortened without decreasing the CR; therefore, it was suggested to improve MR images to avoid motion artifact.

Evaluation of liver function in patients with liver cirrhosis and chronic liver disease using functional liver imaging scores at different acquisition time points

Purpose: This paper aims to explore whether functional liver imaging score (FLIS) based on Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) images at 5, 10, and 15 min can predict liver function in patients with liver cirrhosis or chronic liver disease and its association with indocyanine green 15-min retention rate (ICG-R₁₅), Child-Pugh (CP) score, albumin-bilirubin (ALBI) score, and model for end-stage liver disease (MELD) score. In addition, it also examines the inter- and intra-observer consistency of FLIS and three FLIS parameters at three different time points. Methods: This study included 110 patients with chronic liver disease (CLD) or liver cirrhosis (LC) (93 men, 17 women; mean ± standard deviation = 56.96 ± 10.16) between July 2019 and May 2022. FLIS was assigned in accordance with the sum of the three hepatobiliary phase characteristics, all of which were scored on the 0-2 ordinal scale, including the biliary excretion, hepatic enhancement and portal vein signal intensity. FLIS was calculated independently by two radiologists using transitional and hepatobiliary phase images at 5, 10, and 15 min after enhancement. The relationship between FLIS and three FLIS quality scores and the degree of liver function were evaluated using Spearman's rank correlation coefficient. The ability of FLIS to predict hepatic function was investigated using receiver operating characteristic (ROC) curves. Results: Intra- and inter-observer intraclass correlation coefficients (ICCs) (ICC = 0.937-0.978, 95% CI = 0.909-0.985) for FLIS at each time point indicated excellent agreement. At each time point, FLIS had a moderate negative association with liver function classification (r = [-0.641]-[-0.428], p < 0.001), and weak to moderate correlation with some other clinical parameters except for creatinine (p > 0.05). FLIS showed moderate discriminatory ability between different liver function levels. The area under the ROC curves (AUCs) of FLIS at 5, 10, and 15 min after enhancement to predict ICG-R₁₅ of 10% or less were 0.838, 0.802, and 0.723, respectively; those for predicting ICG-R₁₅ greater than 20% were 0.793, 0.824, and 0.756, respectively; those for predicting ICG-R₁₅ greater than 40% were 0.728, 0.755, and 0.741, respectively; those for predicting ALBI grade 1 were 0.734, 0.761, and 0.691, respectively; those for predicting CP class A cirrhosis were 0.806, 0.821, and 0.829, respectively; those for predicting MELD score of 10 or less were 0.837, 0.877, and 0.837, respectively. No significant difference was found in the AUC of FLIS at 5, 10 and 15 min (p > 0.05). Conclusion: FLIS presented a moderate negative correlation with the classification system of hepatic function at a delay of 5, 10, and 15 min, and patients with LC or CLD were appropriately stratified based on ICG-R₁₅, ALBI grade, MELD score, and CP classification. In addition, the use of FLIS to evaluate liver function can reduce the observation time of the hepatobiliary period.

The ALBI score: From liver function in patients with HCC to a general measure of liver function

The (albumin-bilirubin) ‘ALBI’ score is an index of ‘liver function’ that was recently developed to assess prognosis in patients with hepatocellular carcinoma, irrespective of the degree of underlying liver fibrosis. Other measures of liver function, such as model for end-stage liver disease (MELD) and Child-Pugh score, which were introduced for specific clinical scenarios, have seen their use extended to other areas of hepatology. In the case of ALBI, its application has been increasingly extended to chronic liver disease in general and in some instances to non-liver diseases where it has proven remarkably accurate in terms of prognosis. With respect to chronic liver disease, numerous publications have shown that ALBI is highly prognostic in patients with all types and stages of chronic liver disease. Outside of liver disease, ALBI has been reported as being of prognostic value in conditions ranging from chronic heart failure to brain tumours. Whilst in several of these reports, explanations for the relationship of liver function to a clinical condition have been proposed, it has to be acknowledged that the specificity of ALBI for liver function has not been clearly demonstrated. Nonetheless, and similar to the MELD and Child-Pugh scores, the lack of any mechanistic basis for ALBI’s clinical utility does not preclude it from being clinically useful in certain situations. Why albumin and bilirubin levels, or a combination thereof, are prognostic in so many different diseases should be studied in the future.