A study published in the scientific journal European Radiology with the participation of researchers from the D’Or Institute for Research and Education (IDOR), the Federal University of Rio de Janeiro (UFRJ), and the Institute for Collective Health Studies of UFRJ used the magnetic resonance imaging with gadoxetic acid, a hepatobiliary contrast that is captured liver cells (hepatocytes), to assess liver function in patients with cirrhosis. The researchers compared the results obtained in the tests with the indices observed in other indicators for the identification of cirrhosis and classification of the severity of the disease. 

Cirrhosis of the liver is one of the leading causes of death worldwide. “Cirrhosis is characterized by a structural alteration of the liver associated with the development of fibrosis. In more advanced stages of the disease, alteration of liver function is observed, in addition to the development of complications, such as ascites, encephalopathy, digestive hemorrhage”, informs Dr. Renata Perez, coordinator of the study and researcher at IDOR.  

The assessment of liver function in cirrhosis is extremely important as it is directly related to the risk of complications and death. This assessment is usually performed based on clinical and laboratory criteria, as is done in the Child-Pugh Score and the MELD Score (Model for End-stage Liver Disease), used to determine the severity of liver disease. However, there is room for a specific non-invasive marker in these assessments.  

“In more advanced stages, it becomes essential to estimate the degree of liver failure, and gadoxetic acid MRI can contribute to assessing the severity of liver disease,” he adds. MRI using gadoxetic acid can become an important method for estimating liver function, with the relative enhancement index (REI) being one of the most accurate. The authors of the study report that REI was chosen because it uses the signal intensity of the liver during MRI in the pre-contrast phase and in the intracellular (hepatobiliary) phase, adjusted for liver volume. Liver volume needs to be considered in the calculation of liver function because of its relationship to the number of hepatocytes.  

The study included 60 patients diagnosed with liver cirrhosis based on clinical, laboratory and imaging tests. All patients underwent gadoxetic acid magnetic resonance imaging with REI measurement and indocyanine green clearance test at an interval of 2 weeks. Blood samples were collected for laboratory analysis on the same day as the indocyanine green test to calculate Child-Pugh and MELD scores.  

Among the patients, 48% had hepatitis C as the most frequent cause of cirrhosis. The study involved a group of 60 patients consisting of 20 Child A, 20 Child B, and 20 Child C patients, the latter group with more severe patients. 

The researchers observed correlations between REI and liver function quantified by Child-Pugh and MELD scores and indocyanine green clearance rate. When they performed the specific investigation in each Child-Pugh class, the correlation between REI and indocyanine green test was weak only among patients with Child-Pugh C. The researchers suggest that this finding may be related to the occurrence of portosystemic shunts, observed in liver cirrhosis and more frequent in patients with severe liver disease.  

In addition, REI-assisted MRI was successful in differentiating good and poor liver function groups. REI values below 73 indicate severe liver dysfunction, values between 73-135 indicate moderate liver dysfunction, and REI values > 135 indicate preserved liver function.   

Despite the limited number of patients, the study is promising to consider that it has a good representation for each Child-Pugh score group. It is worth noting that it still has a relevant number of patients in the Child-Pugh C group compared to other studies. The authors demonstrate a good correlation between the results of MRI measured by REI and other parameters used to assess liver function. REI allows the classification of cirrhotic patients and can be used as additional information in the routine evaluation of patients undergoing MRI with the use of gadoxetic acid contrast.