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Background The Liver Imaging Reporting and Data System (LI‐RADS) is widely adopted for noninvasive diagnosis of hepatocellular carcinoma (HCC). It's updated to version 2018 recently, with some major changes compared with v2017. However, the diagnostic performance of LI‐RADS v2018 and its difference with v2017 are yet to be validated. Purpose To compare the diagnostic performances of LI‐RADS on MR for diagnosing HCC between v2017 and v2018. Study Type Retrospective. Subjects In all, 181 patients with 217 hepatic observations (146 HCCs, 16 non‐HCC malignancies and 55 benign lesions) with liver MRI and pathological or follow‐up imaging diagnoses. Field Strength/Sequence 1.5 T or 3 T MRI. Dual‐echo T1WI, T2WI, diffusion‐weighted imaging, and a liver acquisition with volume acceleration. AssessmentImages were independently interpreted by three radiologists, and then in consensus for observations with different LR categories, according to LI‐RADS v2017 and v2018, separately. Statistical Tests Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (+LR), and Youden index. Results When adopting LR‐5 as a predictor of HCC, the sensitivity (80.8% vs. 71.2%), NPV (69.6% vs. 60.7%), and accuracy (83.9% vs. 77.9%) were all increased for LI‐RADS v2018 compared with v2017, with a greater Youden index (0.709 vs. 0.627). However, the diagnostic performances of MRI for diagnosing HCC were not changed while adopting LR‐4/5 as a predictor. The threshold growths of 76% (19/25) observations in v2017 were revised to subthreshold growth in v2018, and 16 LR‐4 observations in v2017 were changed to LR‐5 based on v2018. Data Conclusion The diagnostic performance of LI‐RADS v2018 for diagnosing HCC is superior to v2017, with a greater sensitivity, NPV, and accuracy. The revisions in v2018 mainly affect the categorization when adopting LR‐5 as a predictor of HCC. Level of Evidence: 4 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;50:746–755.

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of the femoral head: using CT, MRI and gross specimen to characterize the location, shape and size of the lesion. Br J Radiol 2015;88:20140508. FULL PAPER Osteonecrosis of the femoral head: using CT, MRI and gross specimen to characterize the location, shape and size of the lesion The results were compared with findings from coronal sectional gross specimens. Two radiologists independently measured the volume of necrotic lesions from CT and MR images using computer software, and the results were averaged. The volume of specimens' necrotic lesion was measured using the water displacement method.Results: There was a high degree of consistency between CT, MRI and the coronal sectional gross specimen on the location, shape and spatial structure of lesions.Differences of the lesion volume measured from CT and MR images were not statistically significant between two radiologists. The necrotic lesion volumes measured from CT and MR images and gross specimens were 22.07 6 5. Osteonecrosis of the femoral head (ONFH) is a common disease of the hip joint. If untreated, 80% of patients with ONFH will suffer the collapse of femoral head articular surface in a few years of disease progression.1 Once the femoral head collapses, osteoarthritis becomes inevitable and function of the hip joint will be seriously affected, which eventually will lead to artificial joint replacement. 2,3Although hip replacement is an effective approach to relieve pain and improve hip function in the short term, its long-term performance remains unsatisfactory.4,5 Furthermore, non-traumatic ONFH typically occurs in young adults and involves both hips. On the other hand, not all ONFH will progress to femoral head collapse.6 Therefore, being able to accurately predict the risk of femoral head collapse according to the disease severity and to take appropriate therapeutic measures are critical to preserve the hip joint and improve the prognosis of ONFH. 7 Studies have shown that the size and location of necrotic lesions are major factors associated with femoral head collapse.6-9 Although various approaches have been reported to illustrate the lesion location and size, all were based on MRI and/or radiographs.6-11 As a main imaging modality for diagnosis of ONFH, CT can clearly display ONFH that is in Association Research Circulation Osseous (ARCO) stage II or above. Multislice CT can achieve isotropic resolution. Volume data acquired from axial scans can be used to reconstruct in any direction to observe lesions. But so far, there has been no study that reports the feasibility and accuracy of using CT to measure the size of ONFH lesions. We hypothesized that CT and MRI could achieve highly consistent results in illustrating the size, shape and location of ONFH lesions in ARCO stage II and above, and both methods can be used to assess the risk of necrotic femoral head collapse.The objectives of this study are (1) to investigate the accuracy of using CT to capture the size, location, shape and spatial structural relationship of the necrotic lesion by com...

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