Related Experiment Video
Updated: Mar 8, 2026
Safety Precautions and Operating Procedures in an ABSL-4 Laboratory: 4. Medical Imaging Procedures
Published on: October 3, 2016
Liver imaging reporting and data system category 4 observations in MRI: Risk factors predicting upgrade to category 5
Keitaro Sofue1,2, Lauren M B Burke3, Viragi Nilmini3
1Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.
Purpose:
To identify demographic and imaging features in magnetic resonance imaging (MRI) that are associated with upgrade of Liver Imaging Reporting and Data System (LI-RADS) category 4 (LR-4) observations to category 5 (LR-5), and to assess their effects on risk of upgrade and time to upgrade.
Materials And Methods:
Institutional Review Board approval was obtained for this retrospective, dual-institution Health Insurance Portability and Accountability Act (HIPAA)-compliant study. Radiologists reviewed 1.5T and 3T MRI examinations for 181 LR-4 observations in 139 patients, as well as follow-up computed tomography (CT) and MRI examinations and treatment. A stepwise multivariate Cox proportional hazards model analysis was performed to identify predictive risk factors for upgrade to LR-5, including patient demographics and LI-RADS imaging features. Overall cumulative risk of upgrade was calculated by using the Kaplan-Meier method. The cumulative risks were compared in the presence/absence of significant predictive risk factors using the log-rank test.
Results:
The independent significant predictive risk factors in the 56 LR-4 observations that upgraded to LR-5 were mild-moderate T2 hyperintensity (P < 0.001; hazard ratio = 1.84), growth (P < 0.001; hazard ratio = 3.71), and hepatitis C infection (P = 0.02; hazard ratio = 1.69). The overall 6-month cumulative risk of upgrade was 32.7%. The 6-month cumulative risk rate was significantly higher in the presence of T2 hyperintensity (P = 0.03; 48.1% vs. 25.4%).
Conclusion:
For LR-4 observations, mild-moderate T2 hyperintensity, threshold growth, and hepatitis C infection are associated with significantly higher risk of upgrade to LR-5. Although mild-moderate T2 hyperintensity was the most useful risk factor for predicting upgrade, actual risk level was only mildly elevated, and the risk of upgrade associated with LR-4 observations is similar across subtypes.
Level Of Evidence:
3 Technical Efficacy: Stage 5 J. MAGN. RESON. IMAGING 2017;46:783-792.
Insights
Mild-moderate T2 hyperintensity, growth, and hepatitis C infection predict upgrade of Liver Imaging Reporting and Data System (LI-RADS) category 4 to category 5 observations. These factors increase the risk of upgrade, aiding in risk stratification for hepatocellular carcinoma surveillance.
Area of Science:
- Radiology
- Hepatocellular Carcinoma Surveillance
- Medical Imaging Analysis
Background:
- Liver Imaging Reporting and Data System (LI-RADS) categorizes liver lesions on imaging.
- Distinguishing between LR-4 and LR-5 categories is crucial for patient management.
- Predictive factors for upgrade from LR-4 to LR-5 require further elucidation.
Purpose of the Study:
- To identify demographic and imaging features associated with upgrade from LR-4 to LR-5 observations.
- To assess the impact of these features on the risk and timing of upgrade.
- To improve risk stratification for hepatocellular carcinoma (HCC) in patients with LR-4 observations.
Main Methods:
- Retrospective analysis of 181 LR-4 observations in 139 patients across two institutions.
- Review of 1.5T and 3T MRI examinations, including follow-up CT and MRI.
- Stepwise multivariate Cox proportional hazards model and Kaplan-Meier analysis to identify predictive factors and cumulative risk.
Main Results:
- Mild-moderate T2 hyperintensity (HR=1.84), growth (HR=3.71), and hepatitis C infection (HR=1.69) were significant predictors of upgrade to LR-5.
- The overall 6-month cumulative risk of upgrade was 32.7%.
- Presence of T2 hyperintensity significantly increased the 6-month cumulative risk of upgrade (48.1% vs. 25.4%).
Conclusions:
- Mild-moderate T2 hyperintensity, threshold growth, and hepatitis C infection are key predictors for LR-4 to LR-5 upgrade.
- While T2 hyperintensity is a strong predictor, the overall risk elevation is mild.
- These findings aid in refining risk assessment for LR-4 observations in HCC surveillance.
