Response Stratification and Survival Analysis of Hepatocellular Carcinoma Patients Treated With Intra-arterial Therapy Using MR Imaging-Based Arterial Enhancement Fraction

Purpose: To investigate the feasibility that arterial enhancement fraction (AEF) is associated with response of hepatocellular carcinoma (HCC) following intra-arterial therapy (IAT) and to compare AEF response with currently used tumor response metrics. Materials and Methods: The AEF, Response Evaluation Criteria in Solid Tumors (RECIST), modified RECIST (mRECIST), and European Association for the Study of the Liver (EASL) of the largest treated index lesion and AEF of the tumor-free hepatic parenchyma was measured on representative axial images in 131 patients (108 male; mean age, 61.9 years). Clinical measures and patient survival were assessed. Statistical analysis included Wilcoxon signed-rank test and the COX proportional hazards model. Results: After IAT, the mean AEF of the tumor decreased by 22% (66.7-44.8%, P < 0.0001), while the mean AEF of the tumor-free parenchyma remained unchanged (27.2-26.5%, P = 0.50). Median survival of all 131 patients with liver cancer was 17 months. Patients were stratified into AEF-responders if they had an AEF-decrease >= 35% (AEF-responders: n = 67; AEF-nonresponders: n = 64). AEF-responders survived longer than nonresponders (34.8 months versus 10.8 months, hazard ratio = 0.39; P< 0.0001). Responders according to RECIST, mRECIST, or EASL did not survive significantly longer compared with nonresponders. Conclusion: Evaluating the AEF values based on triphasic MRI is associated with tumor response in patients with unresectable HCC treated with IAT.