title: In vivoSonothrombolysis of Ear Marginal Vein of Rabbits Monitored with High-frequency Ultrasound Needle Transducer.
abstract: Ultrasound (US) is known to enhance thrombolysis when thrombolytic agents and/or microbubbles are injected into the targeted vessels. In this research, high-intensity US (1 MHz, 7 W/cm2, 30 % duty cycle) was appliedin vivoto the ear marginal vein of three rabbits which was occluded by either laser photothrombosis or thrombin, right after the injection of 0.3~0.6 cc of microbubbles (13 × 108bubbles/ml of concentration) through the other ear vein without using any thrombolytic agent. To determine the effect of the sonothrombolysis, the blood flow velocity near the occlusion site in the vein was measured by a custom-made 40-MHz US needle transducer and its corresponding Doppler US system. The Doppler spectra show that the blood flow velocity recovered from total occlusion after three 10-minute high-intensity US treatments. Fluorescein angiography was employed to confirm the opening of the vessel occlusion. A control study of three rabbits with only the microbubble injection showed no recovery on the occlusion in 3 hours. The results show that the sonothrombolysis in the rabbit ear marginal vein can be achieved with microbubbles only. The results of cavitation measurements indicate that the mechanism of sonothrombolysis is probably due to the cavitation induced by the microbubbles. Without the need of applying any thrombolytic agent, high-intensity US has high potential for therapies targeting on small blood vessels.
authors.affiliation: NIH Resource Center for Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Ruimin
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Ocean System Engineering, Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, Korea 690-756.
authors.forename: Dong-Guk
authors.initials: DG
authors.lastname: Paeng
authors.affiliation: NIH Resource Center for Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Kwok Ho
authors.initials: KH
authors.lastname: Lam
authors.affiliation: NIH Resource Center for Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Qifa
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: NIH Resource Center for Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: K Kirk
authors.initials: KK
authors.lastname: Shung
authors.affiliation: Division of Ophthalmology and Visual Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 950-2181, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Matsuoka
authors.affiliation: Doheny Eye Institute, University of Southern California, Los Angeles, CA 90033, USA.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Humayun
keywords: Microbubbles; Rabbit ear marginal vein; Sonothrombolysis; Therapeutic ultrasound