Real‐time Contrast‐Enhanced Sonographically Guided Biopsy or Radiofrequency Ablation of Focal Liver Lesions Using Perflurobutane Microbubbles (Sonazoid)

Objectives To evaluate the utility of Kupffer‐phase imaging by real‐time contrast‐enhanced sonography using the perflurobutane microbubble contrast agent Sonazoid (GE Healthcare, Oslo, Norway) in guiding biopsy or radiofrequency (RF) ablation of focal liver lesions. Methods A total of 75 patients (mean age, 59.7 years) who were referred for percutaneous biopsy (n = 42) or RF ablation (n = 33) were included in the study. Grayscale sonography and contrast‐enhanced sonography using Sonazoid were performed in all patients before the procedure. The conspicuity of each targeted liver lesion on grayscale sonography, vascular‐phase contrast‐enhanced sonography, and Kupffer‐phase contrast‐enhanced sonography was graded using a 5‐point scale. Lesion detection rates were calculated, and the conspicuity of the lesions among the imaging modalities was compared. The technical success of the procedures was also assessed. Results The procedures were conducted in 66 patients (biopsy in 41 and RF ablation in 25) under real‐time guidance by Kupffer‐phase contrast‐enhanced sonography. Lesion detection rates were 77.3% (58 of 75), 84.0% (63 of 75), and 92.0% (69 of 75) on grayscale sonography, vascular‐phase contrast‐enhanced sonography, and Kupffer‐phase contrast‐enhanced sonography, respectively, and were significantly different among the 3 modalities ( P = .034). Overall, lesion conspicuity was significantly increased on vascular‐phase and Kupffer‐phase contrast‐enhanced sonography compared to grayscale sonography ( P < .001). Technical success rates for the procedures were 95.2% (40 of 42) for biopsy and 69.7% (23 of 33) for RF ablation. Conclusions Kupffer‐phase imaging by contrast‐enhanced sonography using Sonazoid increases the conspicuity of the liver lesions compared to grayscale sonography, and it is useful for real‐time guidance of percutaneous biopsy or RF ablation of focal liver lesions.