title: Optimization of ultrasound parameters of myocardial cavitation microlesions for therapeutic application.
abstract: Intermittent high intensity ultrasound scanning with contrast microbubbles can induce scattered cavitation microlesions in the myocardium, which may be of value for tissue reduction therapy. Anesthetized rats were treated in a heated water bath with 1.5 MHz focused ultrasound pulses, guided by an 8 MHz imaging transducer. The relative efficacy with 2 or 4 MPa pulses, 1:4 or 1:8 trigger intervals and 5 or 10 cycle pulses was explored in six groups. Electrocardiogram premature complexes (PCs) induced by the triggered pulse bursts were counted, and Evans blue stained cardiomyocyte scores (SCSs) were obtained. The increase from 2 to 4 MPa produced significant increases in PCs and SCSs and eliminated an anticipated decline in the rate of PC induction with time, which might hinder therapeutic efficacy. Increased intervals and pulse durations did not yield significant increases in the effects. The results suggest that cavitation microlesion production can be refined and potentially lead to a clinically robust therapeutic method.
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI, USA. Electronic address: douglm@umich.edu.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Miller
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI, USA.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Dou
authors.affiliation: Department of Pediatrics, University of Michigan Health System, Ann Arbor, MI, USA.
authors.forename: Gabe E
authors.initials: GE
authors.lastname: Owens
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, MI, USA.
authors.forename: Oliver D
authors.initials: OD
authors.lastname: Kripfgans
mesh_terms: D000818:Animals; D005117:Cardiac Complexes, Premature / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D003287:Contrast Media / Q000627:therapeutic use; D004452:Echocardiography / Q000379:methods*; D004562:Electrocardiography; D005070:Evans Blue; D008297:Male; D045423:Microbubbles / Q000627:therapeutic use; D032383:Myocytes, Cardiac / Q000473:pathology; D009336:Necrosis; D017207:Rats, Sprague-Dawley; D014159:Transducers; D014464:Ultrasonic Therapy / Q000379:methods*
chemical_list: D003287:Contrast Media; D005070:Evans Blue
keywords: Arrhythmia; Cardiac myocyte necrosis; Hypertrophic cardiomyopathy; Myocardial contrast echocardiography