Characterization of Hyperintense Nodules on Precontrast T1-weighted MRI: Utility of Gadoxetic Acid-Enhanced Hepatocyte-Phase Imaging

Purpose: To evaluate the utility of gadoxetic acid-enhanced hepatocyte-phase magnetic resonance imaging (MRI) in characterization of T1-weighted hyperintense nodules within cirrhotic liver. Materials and Methods: This retrospective study was approved by our Institutional Review Board. Thirty-four nodules hyperintense in unenhanced T1-weighted MRI with histopathological confirmation from a collection of 19 patients were included. Tumor size, signal intensity on T1-weighted, and T2-weighted imaging as well as enhancement patterns on contrast-enhanced dynamic/hepatocyte-phase imaging were recorded. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of hepatocyte-phase imaging. Results: Evaluation of the nodules with standard of reference revealed 15 dysplastic nodules (DN), seven well-differentiated hepatocellular carcinomas (wHCC), and 12 moderately differentiated HCCs (mHCC). The mean size of dysplastic nodules was smaller than that of HCCs (P < 0.001). Using the HCC criteria (T2W or arterial enhancement followed with portal venous washout), 11/19 HCC were correctly characterized. Using solely hypointensity (compared to the surrounding liver parenchyma) during the hepatocyte phase as the criterion, 18/19 HCC were correctly characterized. There were seven additional HCCs diagnosed with hepatocyte-phase imaging (P = 0.02). Conclusion: Gadoxetic acid-enhanced MRI with hepatocyte-phase imaging is superior to gadoxetic acid-enhanced MRI with conventional criteria alone in characterization of T1W hyperintense nodules.