title: Diagnostic Ultrasound High Mechanical Index Impulses Restore Microvascular Flow in Peripheral Arterial Thromboembolism.
abstract: We sought to explore mechanistically how intermittent high-mechanical-index (MI) diagnostic ultrasound impulses restore microvascular flow. Thrombotic microvascular obstruction was created in the rat hindlimb muscle of 36 rats. A diagnostic transducer confirmed occlusion with low-MI imaging during an intravenous microbubble infusion. This same transducer was used to intermittently apply ultrasound with an MI that produced stable or inertial cavitation (IC) for 10 min through a tissue-mimicking phantom. A nitric oxide inhibitor, L-Nω-nitroarginine methyl ester (L-NAME), was pre-administered to six rats. Plateau microvascular contrast intensity quantified skeletal microvascular blood volume, and postmortem staining was used to detect perivascular hemorrhage. Intermittent IC impulses produced the greatest recovery of microvascular blood volume (p < 0.0001, analysis of variance). Nitric oxide inhibition did not affect the skeletal microvascular blood volume improvement, but did result in more perivascular hemorrhage. IC inducing pulses from a diagnostic transducer can reverse microvascular obstruction after acute arterial thromboembolism. Nitric oxide may prevent unwanted bio-effects of these IC pulses.
authors.affiliation: University of Nebraska Medical Center, Omaha, Nebraska, USA. Electronic address: trporter@unmc.edu.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Porter
authors.affiliation: University of Nebraska Medical Center, Omaha, Nebraska, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Radio
authors.affiliation: University of Nebraska Medical Center, Omaha, Nebraska, USA.
authors.forename: John
authors.initials: J
authors.lastname: Lof
authors.affiliation: Swarthmore College, Swarthmore, Pennsylvania, USA.
authors.forename: Carr
authors.initials: C
authors.lastname: Everbach
authors.affiliation: Philips Healthcare, Bothell, Washington, USA.
authors.forename: Jeffry E
authors.initials: JE
authors.lastname: Powers
authors.affiliation: Philips Research North America, Briarcliff Manor, New York, USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Vignon
authors.affiliation: Philips Research North America, Briarcliff Manor, New York, USA.
authors.forename: William T
authors.initials: WT
authors.lastname: Shi
authors.affiliation: University of Nebraska Medical Center, Omaha, Nebraska, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Xie
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D055806:Microvessels; D058729:Peripheral Arterial Disease / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013923:Thromboembolism / Q000628:therapy*; D014463:Ultrasonography / Q000379:methods*
keywords: Cavitation; Diagnostic ultrasound; Microvascular obstruction; Nitric oxide