A Comparative Study of SonoVue and Sonazoid for Contrast-Enhanced Ultrasound CT/MRI Fusion Guidance During Radiofrequency Ablation of Poorly Visualized Hepatic Malignancies: A Prospective Intra-Individual Analysis

Purpose: This study aimed to evaluate the effectiveness of two contrast agents, SonoVue (SV) and Sonazoid (SZ), by comparing them intra-individually in contrast-enhanced ultrasound (CEUS)-CT/MRI fusion imaging (FI) to improve the visibility of inconspicuous liver malignancies on B-mode sonography for guiding percutaneous radiofrequency ablation (RFA). Additionally, the radiologists' preference between SonoVue- CT/MRI FI (SV-FI) and Sonazoid-CT/MRI FI (SZ-FI) was determined. Methods: This prospective study enrolled 23 patients with inconspicuous hepatic malignancies (<= 3 cm) on B-mode US who underwent both SV-FI and SZ-FI for RFA guidance. The patients underwent real-time CEUS FI with CT/MRI on the same day, utilizing both SV and SZ with at least 15-min intervals. Tumor visibility and radiologists' preferences were assessed and graded using a 4-point scale during the dynamic phases of both SV-FI and SZ-FI and the Kupffer phase of SZ-FI. Results: The tumor visibility scores obtained from CEUS-CT/MRI FI were significantly better than those obtained from US-FI. Indeed, SV-FI and SZ-FI demonstrated comparable visibility scores when corresponding phases were compared (p > 0.05). However, the Kupffer phase images of SZ-FI displayed superior visibility scores (3.70 +/- 0.56 vs. 2.96 +/- 0.88; p = 0.002) than the late vascular phase images of SV-FI. The radiologists favored SZ-FI in many cases, exhibiting moderate inter-observer agreement (Kappa value = 0.587; 95% CI, 0.403-0.772). Conclusion: Although CEUS-CT/MRI FI with either SV or SZ substantially improved the visibility of inconspicuous tumors on US-CT/MRI FI, radiologists preferred SZ to SV to guide the RFA procedure.