Added Value of Gadoxetic Acid-enhanced Liver Magnetic Resonance Imaging for Diagnosis of Small (10-19 mm) or Atypical Hepatic Nodules at Contrast-enhanced Computed Tomography: A Prospective Study

In terms of confirmative diagnosis, HCC is unique compared with other malignant tumors, as it can be diagnosed noninvasively based on its characteristic imaging features, that is, arterial hyperenhancement (washin) and hypoenhancement (washout) on portal or delayed phase at contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) using extracellular contrast media (ECCM). According to Liver Imaging Reporting and Data System (LI-RADS), hypointensity and isointensity on hepatobiliary phase (HBP) at gadoxetic acid-enhanced MRI are suggestive of malignancy and benignity, respectively, and those features are uniquely provided by only hepatocyte-specific contrast agent. However, these features are not included in diagnostic criteria because of its non-specificity, and indeed, gadoxetic acid-enhanced MRI is not yet included in AASLD and EASL guidelines as a diagnostic modality. If gadoxetic acid-enhanced MRI would provide better performance to diagnose HCC than CT, gadoxetic acid-enhanced MRI should be considered as a next step before biopsy in those small and/or atypical nodules to avoid potential diagnostic pitfall and morbidity, which is currently depending on physicians' decision. Thus, it would be valuable to evaluate whether gadoxetic acid-enhanced liver MRI would provide additional value for characterizing atypical or small (1~2cm) hepatic nodules at CT and to reduce the necessity of biopsy in patients with high risk of HCC.

Therefore, the purpose of this study is to evaluate added value of gadoxetic acid-enhanced MRI for diagnosis of HCC in patients with small (10-19mm) or atypical hepatic nodules at CT.