To compare the category of unenhanced combined contrast enhanced MR imaging (MR) and Multiphasic CT (CT) in the diagnosis of HCC based on LI-RADS 2014 in patients with cirrhosis induced by HBV infection.Subjects: A total of 98 patients (80M/18F; mean age, 53y; age range, 34-76y) who met the following criteria were enrolled in this study: a) The patient was confirmed with cirrhosis induced by HBV infection; b) There was suspected HCC on the basis of a previous ultrasonographic examination or an elevated AFP level; c) The patient underwent both CT and MRI within 30 days; d) The patient was diagnosed by partial hepatectomy or liver biopsy. A total of 106 HCCs were included. Image assessment: The images were qualitatively analyzed by 1 radiologists independently. The interval between the 2 imaging sets (CT and MRI) was at least 4 weeks. The reader recorded the major features and ancillary features, and categorized all detected lesions by using the criteria of LI-RADS 2014. Statistical analysis: The difference between the LI-RADS category of CT and MRI was tested by Wilcoxon test. The constituent ratios, mean value were used to show the overall trends between the two examinations. The difference of major and ancillary features between CT and MRI were compared by Chi-square test.Both examinations were mainly consist of LR-4 and LR-5. For CT, the proportion of LR-4 was 41%, LR-5 was 12.3%; while for MRI, the proportion of LR-4 was 34%, LR-5 was 56.6% (Fig. 1). The mean value of the final category of 102 lesions (after leaving 4 lesions given LR-M on CT and/or MRI out) was 4.05±1.17 and 4.49±0.66 on CT and MRI. For the main features, only the capsule appearance showed significant difference between CT and MRI (p＜0.01), with the occurrence of 13.2% and 50.9% (Tab.1). For the ancillary features, mosaic architecture, intra-lesional fat and lesional fat sparing showed significant difference between CT and MRI (p＜0.01). Two ancillary features only for MRI, mild-moderate T2 hyper-intensity and restricted diffusion, showed relatively high occurrence, 89.6% and 87.7% respectively (Tab.2).Unenhanced combined contrast-enhanced MRI elevates the LI-RADS 2014 HCC probability category compared with multiphasic CT in patients with cirrhosis induced by HBV infection.MDCT and MR imaging are playing increasing role in the diagnosis of HCC since the technical advances have improved the ability of the imaging modalities to demonstrate the typical features of HCC¹. This trend has been reflected in the changing of clinical practice guidelines². While until now, no guideline has pointed out the priority of CT and MR, which may cause confusions of the doctors when choosing the imaging examination. Liver Imaging Reporting and Data System (LI-RADS) is a guideline focus on the imaging diagnosis of HCC based on CT and MR imaging³. It give radiologists a criteria to get a confidence level of the liver lesion. We tried to use the latest LI-RADS version to figure out the difference between CT and MR imaging in the diagnosis of HCC. MR showed higher LI-RADS scores of HCC compared with CT, which revealed that MR give a higher malignant grade and a higher confidence lever than CT. And we also tried to find the reason why MR showed higher LI-RADS scores than CT for HCC based on the imaging features defined by LI-RADS. MR had higher occurrence compared with CT for some imaging features, this may because the better soft tissue resolution of MR. Based on our study, we find that MRI can elevate the LI-RADS category and may be recommended in the initial evaluation of suspected HCC priority to CT.