The Value of Gadoxetic Acid-Enhanced Hepatospecific Phase MR Imaging for Characterization of Hepatocellular Nodules in the Cirrhotic Liver

Introduction

Hepatocellular carcinoma (HCC) is the most common primary liver cancer in patients with chronic liver disease, particularly hepatitis B and C virus-related cirrhosis. In these patients HCC develops in a multistep manner known as hepatocarcinogenesis, which evolves from regenerative nodule through high-grade dysplastic nodule (DN) and early HCC, and leads to overt HCC.

Abstract

INTRODUCTION

Owing to significant overlaps between the dynamic imaging findings of dysplastic nodule (DN) and hepatocellular carcinoma (HCC) in cirrhotic livers, we investigated the added value of gadoxetic acid MR imaging, which combines dynamic and hepatospecific properties.

OBJECTIVES

The purpose of this study is to retrospectively assess the value of adding hepatospecific phase images of gadoxetic acid enhanced MR imaging to unenhanced and dynamic enhanced MR images for the characterization of HCC and DN in patients with cirrhosis.

METHODS

A total of 34 patients with 39 HCCs and 15 DNs were enrolled and all lesions were pathologically proved except for 16 HCCs. Patients underwent gadoxetic acid enhanced MR examination, including dynamic and 20 min hepatospecific phase imaging using a 1.5-Tesla system. Two radiologists independently reviewed two sets of MR images: set A, unenhanced (T1- and T2-weighted) and gadoxetic acid enhanced dynamic images; set B, unenhanced (T1- and T2-weighted) and gadoxetic acid enhanced dynamic images plus 20 min hepatospecific phase images. For each set and each observer, the diagnostic accuracy was compared using ROC curve analysis (Az). Sensitivity and specificity values were also calculated.

RESULTS

For both observers, Az values for the diagnosis of HCC resulted to be higher with the addition of hepatospecific phase images, with a significant improvement for the less experienced observer (p=.045). Similarly, sensitivity values significantly increased with the addition of hepatospecific phase images for both observers (p=.044 for observer 1 and p=.025 for observer 2). No significant differences were observed for specificity values.

CONCLUSION

Adding the hepatospecific phase to unenhanced and dynamic gadoxetic acid enhanced MR images helps to differentiate HCC from DN.

Keywords

Gd-EOB-DTPA enhanced MR imaging, dynamic MRI, hepatocellular carcinoma, dysplastic nodule, liver cirrhosis, liver-specific contrast media, magnetic resonance imaging