title: 2MHz ultrasound enhances t-PA-mediated thrombolysis: comparison of continuous versus pulsed ultrasound and standing versus travelling acoustic waves.
abstract: In addition to fibrinolytic enzymes, ultrasound has the potential to enhance thrombolysis. High frequency ultrasound has the advantage that a combination of diagnostic and therapeutic ultrasound with only one device is possible. Therefore, we investigated the optimal high frequency (2 MHz) ultrasound field characteristics and application mode in vitro. Continuous ultrasound significantly enhanced rt-PA mediated thrombolysis: in a travelling wave field thrombolysis was augmented by 49.0 +/- 14.7% and in a standing wave field by 34.8 +/- 7.3%. In an intermittent application mode (1Hz, 10Hz, 100Hz, 1kHz) most efficient results were obtained for both wave fields using 1 Hz (46.4 +/- 10.7% and 39.1 +/- 6.6%, respectively). Referring to a possible in vivo application our in vitro data suggests that an intermittent application of a 2 MHz high frequency ultrasound using a travelling wave field would be the most potent application for lysing blood clots.
authors.affiliation: Department of Internal Medicine II, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pfaffenberger
authors.forename: Branka
authors.initials: B
authors.lastname: Devcic-Kuhar
authors.forename: Karem
authors.initials: K
authors.lastname: El-Rabadi
authors.forename: Martin
authors.initials: M
authors.lastname: Gröschl
authors.forename: Walter S
authors.initials: WS
authors.lastname: Speidl
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Weiss
authors.forename: Kurt
authors.initials: K
authors.lastname: Huber
authors.forename: Ewald
authors.initials: E
authors.lastname: Benes
authors.forename: Gerald
authors.initials: G
authors.lastname: Maurer
authors.forename: Johann
authors.initials: J
authors.lastname: Wojta
authors.forename: Michael
authors.initials: M
authors.lastname: Gottsauner-Wolf
mesh_terms: D000162:Acoustics; D003131:Combined Modality Therapy; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D015912:Thrombolytic Therapy / Q000379:methods*; D013927:Thrombosis / Q000188:drug therapy / Q000378:metabolism / Q000628:therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D014464:Ultrasonic Therapy / Q000379:methods*
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; D010959:Tissue Plasminogen Activator