Predicting Progression to Hypervascular HCC in Hypovascular Hypointense Nodules in Gadoxetic Acid-enhanced MR Images in Patients with Chronic Liver Disease

Objective: To identify patient characteristics and MR imaging features of hypovascular hypointense nodules in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MR imaging in patients with chronic liver disease associated with progression to hypervascular hepatocellular carcinoma (HCC). Materials and Methods: The institutional review board approved this retrospective review of 40 patients with 60 hypovascular hypointense nodules in the HBP of gadoxetic acid-enhanced MR imaging. Univariate and multivariate Cox regression analyses for hypervascular HCC development were used to define variables, including initial nodule size, cause of cirrhosis, history of locoregional therapy of HCC, fat-containing, signal intensity on T1W, T2W, portal and equilibrium phases of dynamic phase, and DW images. The cumulative percentage incidence of hypervascularity and growth rate were calculated using the receiver operating characteristic (ROC) curve. Results: The prevalence of progression to hypervascular HCC was 45% (27 out of 60). The Multivariable Cox analysis of developing hypervascularization was an initial nodule diameter more than 1 cm. (P=0.027; HR 2.52; 95% CI: 1.11,5.74) The mean growth rate was significantly higher in subsequent hypervascular nodules than in those without hypervascularization (P < 0.001). The cumulative risk incidence of hypervascularization at 3, 6, 12, 24 months was 5%, 20%, 35%, 44 %, respectively. Conclusion: An initial nodule diameter of more than 1 cm and nodules with higher growth rates are significant predictive factors for hypervascular transformation of hypovascular hypointense nodules in the  HBP of gadoxetic acid-enhanced MR imaging.