Objective: To investigate the influences of different acoustic pressure and duty cycle on in vitro ultrasound thrombolysis using transcatheter injections of microbubble and urokinase. Methods: An in vitro ultrasound thrombolysis system was designed. And the microbubble solution was prepared. A total of 90 fresh human blood clots were randomly divided into 9 groups, including 8 study groups and a control group. The injections of 0.02 ml microbubble solution and 20000 IU urokinase were performed on all clots. The ultrasonic irradiations were also done in different groups. The duty cycles were 10% stably, while the acoustic pressure was 285 kPa, 512 kPa, 708 kPa and 931 kPa in study groups 1-4, respectively. The acoustic pressures were 931 kPa stably, while the duty cycle was 1%, 2%, 5%, and 10% in study groups 5-8, respectively. The control group was treated as sham ultrasound exposure. The thrombolysis rate of different groups were calculated and compared. High resolution ultrasound was used to observe ultrasonic findings of clots and distribution of microbubble. Results: The microbubble were diffused uniformly and trend to decrease in the clots. For the different acoustic pressure effect study, the thrombolysis rate of study groups 3 and 4 was separately higher than that of control group (both P<0.01), while the thrombolysis rate of study group 4 was higher than that of study group 1 (P<0.05). For the different duty cycle effect study, the thrombolysis rate of study groups 6, 7 and 8 was separately higher than that of control group (all P<0.05), while the thrombolysis rate of study group 8 was higher than that of study group 5 (P<0.01). No statistical difference of the thrombolysis rate was found among another groups (all P>0.05). Conclusion: Transcatheter injections of microbubble and urokinase have an enhanced effect of ultrasound thrombolysis. The parameters of acoustic pressure as 708 kPa and duty cycle more than 2% are favorable.
- Acoustic parameters
- Thrombolytic therapy
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Physiology (medical)