Hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase of gadoxetic acid-enhanced MRI in patients with chronic liver disease: Prediction of malignant transformation

Purpose: To investigate the predictive factors of malignant transformation of hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase images of gadoxetic acid-enhanced MRI (HHN). Materials and Methods: The clinical data and imaging findings of dynamic contrast-enhanced computed tomography (DCE-CT) and gadoxetic acid-enhanced MRI for a total of 103 HHNs in 24 patients with chronic liver disease were retrospectively investigated. After the results of follow-up examinations were investigated, HHNs were categorized into the three groups for each comparison: (1) nodules with enlargement and/or vascularization and others, (2) nodules with only enlargement and others, (3) nodules with only vascularization and others. Enlargement and/or vascularization during the follow-up period were defined as malignant transformation of HHN. The frequency of each clinical datum and imaging finding in each group was compared to identify the predictive factors for malignant transformation in HHN. Results: Multivariate analysis showed that a nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI was a significant predictive factor for the enlargement and/or vascularization of HHN (P < 0.05). On the other hand, the hypoattenuation on the delayed phase imaging of the initial DCE-CT was a significant predictive factor for the enlargement or vascularization of HHN (P < 0.05). Conclusion: A nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI and hypoattenuation on the delayed phase imaging of initial DCE-CT would be helpful for predicting the outcome of HHN in patients with a risk of hepatocellular carcinoma.