Value of Contrast-Enhanced Ultrasound Arrival-Time Parametric Imaging for Differentiating Hepatocellular Adenoma from Focal Nodular Hyperplasia

Abstract Objective Focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) are benign hepatocellular lesions that may show overlapping imaging features but require different clinical management strategies. This study aimed to evaluate the value of arrival-time parametric imaging (ATPI) in differentiating HCA from FNH by characterizing lesion-specific early arterial enhancement patterns and vascular architecture. Materials and methods In this retrospective study, 54 patients (36 FNH, 18 HCA) underwent CEUS between January 2020 and January 2024. Final diagnosis was based on histopathology or typical CT/MRI findings with ≥ 12 months follow-up. CEUS and ATPI features were analyzed, and diagnostic performance of CEUS alone versus CEUS combined with ATPI was compared. Interobserver agreement was assessed using Cohen’s kappa. Results FNH more frequently exhibited centrifugal enhancement, spoke-wheel arteries, and intralesional arterial branches, whereas HCA showed centripetal enhancement and prominent feeding arteries. Compared with CEUS alone, CEUS combined with ATPI improved sensitivity from 77.8% to 94.4%, specificity from 86.1% to 91.7%, accuracy from 83.3% to 92.6%, positive predictive value from 73.7% to 85%, and negative predictive value from 88.6% to 97.1%. Interobserver agreement increased from κ = 0.683 with CEUS alone to κ = 0.757 after ATPI was incorporated. Conclusion ATPI may provide additional information on early arterial enhancement patterns and vascular architecture in FNH and HCA. Although CEUS combined with ATPI showed numerically higher diagnostic performance than CEUS alone, further studies with larger sample sizes are needed to confirm its incremental diagnostic value.