title: Liver imaging reporting and data system category 4 observations in MRI: Risk factors predicting upgrade to category 5.
abstract: 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.
  
  
  
  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.
  
  
  
  The independent significant predictive risk factors in the 56 LR-4 observations that upgraded to LR-5 were mild-moderate T2hyperintensity (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 T2hyperintensity (P = 0.03; 48.1% vs. 25.4%).
  
  
  
  For LR-4 observations, mild-moderate T2hyperintensity, threshold growth, and hepatitis C infection are associated with significantly higher risk of upgrade to LR-5. Although mild-moderate T2hyperintensity 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.
  
  
  
  3 Technical Efficacy: Stage 5 J. MAGN. RESON. IMAGING 2017;46:783-792.
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.|Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Sofue
authors.affiliation: Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Lauren M B
authors.initials: LMB
authors.lastname: Burke
authors.affiliation: Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Viragi
authors.initials: V
authors.lastname: Nilmini
authors.affiliation: Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Madavi
authors.initials: M
authors.lastname: Alagiyawanna
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Muir
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Kingshuk R
authors.initials: KR
authors.lastname: Choudhury
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Jaffe
authors.affiliation: Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Semelka
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.|Center for Advanced Magnetic Resonance Development, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Mustafa R
authors.initials: MR
authors.lastname: Bashir
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008107:Liver Diseases / Q000000981:diagnostic imaging* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011873:Radiology Information Systems; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: MRI; hepatocellular carcinoma; liver; liver imaging reporting and data system