Does contrast ultrasonography damage liver cell?

To confirm whether the microbubble activated by sonication causes liver damage, the authors performed two experiments. Experiment 1 followed Shigeta's experiment. As an ultrasound contrast agent (UCA), Levovist was used and sonicated by Acuson Sequoia™ 512 by Siemens. Wister rats of 300 g were divided into four groups: (A) administration of ultrasonic contrast agent (UCA) and ultrasonic exposure, (B) administration of UCA, (C) ultrasonic exposure, and (D) control. Experiment 1 did not show the evidence of hepatic damage such as Shigeta et al. reported. Hence, we conducted Experiment 2 with a much higher acoustic output. But no clear damage was observed in both optical and electron microscopic specimens.