Change in liver imaging reporting and data system characterization of focal liver lesions using gadoxetate disodium magnetic resonance imaging compared with contrast-enhanced computed tomography

Purpose: The aim of this study was to determine whether gadoxetateenhanced magnetic resonance imaging (MRI) improves lesion characterization in patients at risk for hepatocellular carcinoma compared with computed tomography (CT). Materials and Methods: Forty-nine patients with indeterminate lesions found at contrast-enhanced CTwere prospectively enrolled and imaged using gadoxetate-enhanced hepatobiliary phase (HBP) MRI within 30 days of their initial CT. Three readers graded each lesion at CT and MRI using the Liver Imaging Reporting and Data System (LI-RADS) v2014 major criteria and HBP characterization as an ancillary feature. Patients were followed for an average of 1.8 years to document growth or stability of each lesion. Results: The Liver Imaging Reporting and Data System categorization changed for 71% (52/73) of lesions based on HBP MRI compared with CT, with 30% (22/73) of lesions upgraded and 41% (30/73) of lesions downgraded. Therewas almost perfect agreement between readers for arterial phase hyperintensity and HBP hypointensity, with lower interreader agreement for washout and capsule appearance. On the basis of composite clinical follow-up, lesions that were subsequently classified as hepatocellular carcinoma were assigned a higher LI-RADS category on HBP MRI when compared with CT. Conclusions: For patients with indeterminate lesions seen on contrastenhanced CT, HBPMRI using gadoxetate improves lesion characterization when using LI-RADS v2014 criteria.