Clinicopathologic and Prognostic Differences Between LI ‐ RADS M Targetoid and LI ‐ RADS M Nontargetoid Observations: A Comparative Imaging‐Based Study

ABSTRACT Background Liver Imaging Reporting and Data System M (LR‐M) lesions may appear targetoid or nontargetoid, but their clinicopathologic and prognostic differences remain unclear. Purpose To compare clinical, pathological, and prognostic features of targetoid and nontargetoid LR‐M lesions on dynamic contrast enhanced‐MRI (DCE‐MRI). Study Type Retrospective. Subjects 119 consecutive patients (82 male, mean age = 62.9 ± 10.3 years) with 119 LR‐M observations (75 targetoid, 44 nontargetoid) and at least 2 years of follow‐up. Field Strength/Sequence 1.5T and 3.0T; T2‐weighted fast spin echo sequence, diffusion‐weighted image, and dynamic T1‐weighted‐gradient‐echo sequence using an extracellular contrast agent. Assessment Three radiologists categorized lesions as targetoid or nontargetoid. Clinical, laboratory, imaging, and histopathologic data were collected. Statistical Tests Group differences were evaluated using t ‐tests and chi‐square/Fisher's exact tests. Survival outcomes were assessed using Kaplan–Meier method with log‐rank test and Cox proportional hazards regression. Inverse probability of treatment weighting (IPTW) was applied before survival analysis. A p ‐value < 0.05 was considered significant. Results The nontargetoid group had significantly higher serum AFP (6684.7 ± 15,988 vs. 194.9 ± 898.4 ng/mL), larger lesion size (9.10 ± 5.55 cm vs. 3.55 ± 2.96 cm), cirrhosis (95% vs. 76%), extrahepatic disease (50% vs. 19%), and malignancy (95% vs. 82%). Nontargetoid group showed significantly higher mortality (75% vs. 41%), progression (77% vs. 45%), shorter overall survival (477 ± 629 vs. 1226 ± 1147 days), and time‐to‐progression (333 vs. 1003 days). On multivariable analysis with Cox proportional hazards regression, targetoid morphology was significantly associated with improved overall survival (HR = 0.28) and progression‐free survival (HR = 0.36), whereas histology was not significant (HCC vs. non‐HCC). Data Conclusion Targetoid morphology is significantly associated with improved survival and delayed progression, supporting its role as a prognostic imaging biomarker. Evidence Level 3. Technical Efficacy Stage 5.