Liver Imaging Reporting and Data System v2014 With Gadoxetate Disodium-Enhanced Magnetic Resonance Imaging Validation of LI-RADS Category 4 and 5 Criteria

Objectives: The aim of this study was to validate the Liver Imaging Reporting and Data System (LI-RADS) v2014 category 4 (LR-4) and 5 (LR-5) criteria on gadoxetate disodium-enhanced magnetic resonance imaging (MRI) in patients with chronic liver disease. Materials and Methods: Between January and December 2012, 300 patients with chronic liver disease who had hepatic nodules 3.0 cm or smaller at surveillance ultrasonography and gadoxetate disodium-enhanced MRI were included. LI-RADS category was retrospectively assigned to each nodule onMRI. Final diagnosis was assessed using pathologic diagnosis only (operation or core-needle biopsy) or pathologic and clinical diagnosis (marginal recurrence after treatment or a change in lesion size on follow-up imaging). To validate the LR-4 and LR-5 criteria, the sensitivity, positive predictive value (PPV), and false referral rate for diagnosing hepatocellular carcinoma were examined. Results: Based on major imaging features only, 137 nodules were initially assigned as LR-3, but 133 (97.1%) were upgraded into LR-4 by the presence of ancillary features. Excluding the remaining 4 LR-3 and 3 LR-M nodules, we analyzed 379 nodules in 294 patients, consisting of 211 LR-4 and 168 LR-5 nodules. Using pathologic diagnosis only, the sensitivity and PPV with 95% confidence intervals (CIs) for LR-5 were higher than those for LR-4 (57.3% [50.6-63.7] vs 42.7% [36.3-49.4]; 94.6% [89.0-97.5] vs 82.0% [73.7-88.1]), with a lower false referral rate (5.4%[2.5-11.0] vs 18.0% [11.9-26.3]). Using pathologic and clinical diagnosis, PPV and 95% CI for LR-5 were higher than that for LR-4 (95.2%[90.7-97.7] vs 79.1% [73.1-84.1]), whereas sensitivity and 95% CI for LR-5 was similar to that for LR-4 (48.9% [43.6-54.3] vs 51.1% [45.7-56.4]). Conclusions: In patients with chronic liver disease, LR-5 criteria on gadoxetate disodium-enhanced MRI had excellent PPV for diagnosing hepatocellular carcinoma, whereas LR-4 criteria showed good PPV, but are only of limited use.