Prevalence and clinical significance of discordant LI-RADS^® observations on multiphase contrast-enhanced MRI in patients with cirrhosis

Purpose: To determine the prevalence and clinical significance of discordant LI-RADS^® (Liver Imaging Reporting and Data System) liver observations on multiphase contrast-enhanced (MCE) magnetic resonance imaging (MRI) in patients with cirrhosis. Methods: This cross-sectional study included 93 cirrhosis patients who underwent 1.5 or 3 T MCE MRI for evaluation of hepatocellular carcinoma (HCC). Two abdominal radiologists independently reviewed T1-, T2-, diffusion-weighted unenhanced images as well as MCE T1-weighted fat-suppressed images and reported liver observations using LI-RADS^®. Concordance were recorded for detection (co-detected by both radiologists or not), size category (< 10; 10–19; ≥ 20 mm), and LI-RADS^® category assignment as reportable (LR-3/4/5/M) and actionable (LR-4/5/M). The overall concordance (i.e., concordant in detection, size, and LR-category) was calculated with 95% confidence interval [CI], and separately for detection, size, and LR-category. Clinical significance of discordance was assessed as impact on follow-up imaging, referral for biopsy, liver transplant eligibility, or treatment modality. Results: Reportable and actionable observations were overall concordant between two radiologists only in 32.3% [24.6, 41.0] and 40.1% [29.5, 51.5] of cases, respectively. Poor overall concordance was related to detection concordance of 52.0% [44.3, 59.5] and 62.5% [52.3, 71.8], as well as LR-category concordance of 73.7% [61.6, 83.1] and 70.9% [57.3, 81.6], for reportable and actionable observations, respectively. Discordant LI-RADS^® observations would have impacted clinical management in 30 subjects (43.5%), most (66.7%) of whom were due to discordant detection. Conclusion: Discordant MRI LI-RADS^® observations are common in patients with cirrhosis and may have potential implications for patient management.