Washout appearance in Gd-EOB-DTPA-enhanced MR imaging: A differentiating feature between hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase and focal nodular hyperplasia-like nodules

Purpose: To identify the most reliable imaging features for differentiating hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase (HCC_para) from focal nodular hyperplasia (FNH)-like nodules using Gd-EOB-DTPA-enhanced MRI. Materials and Methods: This was a retrospective study. Twenty patients with HCC_para and 21 patients with FNH-like nodules were included. The following MRI features were evaluated using 3.0 Tesla unit by two radiologists: signal intensity (SI) on T1-, T2-, and diffusion-weighted imaging (DWI), arterial enhancement pattern, washout appearance on the portal venous phase (PVP) and/or transitional phase (TP), uptake pattern on the hepatobiliary phase (HBP), “T2 scar,” “EOB scar,” and chemical shift on in- and out-of-phase images. Multivariate logistic regression analysis was performed to assess MRI features for prediction of HCC_para. Results: Compared with FNH-like nodules, HCC_para had significantly more frequent heterogeneous T1 SI (P < 0.0001), T2 hyperintensity (P = 0.032), heterogeneous arterial enhancement (P < 0.0001), washout appearance on the PVP and/or TP (P < 0.0001), heterogeneous uptake on the HBP (P < 0.0001), absence of “EOB scar” (P < 0.0001), and hyperintensity on DWI (P = 0.004). Multivariate logistic regression analysis revealed washout appearance as the only independent imaging feature associated with HCC_para (odds ratio, 7.019; P = 0.042). Washout appearance also showed the best diagnostic performance with a sensitivity of 90% and a specificity of 100%. Conclusion: Washout appearance on the PVP and/or TP is the most reliable imaging feature for differentiating HCC_para from FNH-like nodules. Level of Evidence: 3. J. MAGN. RESON. IMAGING 2017;45:1599–1608.