Which is the best MRI marker of malignancy for atypical cirrhotic nodules: Hypointensity in hepatobiliary phase alone or combined with other features? Classification after Gd-EOB-DTPA administration

Purpose: To investigate whether the malignancy of atypical nodules in cirrhosis can be identified at gadoxetic-acid-disodium(Gd-EOB-DTPA)-MRI by their hypointensity in the hepatobiliary(HB)-phase alone or combined with any other MR imaging features. Materials and Methods: One hundred eleven atypical nodules detected in 77 consecutive Gd-EOB-DTPA-MRIs were divided, based on arterial-phase behavior, into: Class I, isovascular (n = 82), and Class II, hypervascular without portal/delayed washout (n = 29). The two classes were further grouped based on HB-phase intensity (A/B/C hypo/iso/hyperintensity). Portal/venous/equilibrium-phase behavior and T2w features were also collected. Histology was the gold standard. Per-nodule sensitivity, specificity, negative and positive predictive values (NPV/PPV), and diagnostic accuracy were calculated for HB-phase hypointensity alone, and combined with vascular patterns and T2w hyperintensity. Results: Histology detected 60 benign and 51 malignant/premalignant nodules [10 overt hepatocellular carcinomas (HCCs) and 41 high-grade dysplastic nodules (HGDN)/early HCC]. Class IA contained 31 (94%) malignancies, IB one (3%), and IC only benign lesions. Class IIA had 100% malignancies, IIB three (37.5%) and IIC only two (28.5%). HB-phase hypointensity alone (Classes IIIA) had 88% sensitivity, 91% NPV, and 93% diagnostic accuracy, superior (P < 0.05, P < 0.006, and P < 0.05, respectively) to any other MR imaging feature alone or combined. Conclusion: In atypical cirrhotic nodules, HB-phase hypointensity by itself is the strongest marker of malignancy. J. Magn. Reson. Imaging 2012;36:648657. (C) 2012 Wiley Periodicals, Inc.