Preliminary observations on the spatial correlation between short-burst microbubble oscillations and vascular bioeffects.
The objective of this preliminary study was to examine the spatial correlation between microbubble (MB)-induced vessel wall displacements and resultant microvascular bioeffects. MBs were injected into venules in ex vivo rat mesenteries and insonated by a single short ultrasound pulse with a center frequency of 1 MHz and peak negative pressures spanning the range of 1.5-5.6 MPa. MB and vessel dynamics were observed under ultra-high speed photomicrography. The tissue was examined by histology or transmission electron microscopy for vascular bioeffects. Image registration allowed for spatial correlation of MB-induced vessel wall motion to corresponding vascular bioeffects, if any. In cases in which damage was observed, the vessel wall had been pulled inward by more than 50% of the its initial radius. The observed damage was characterized by the separation of the endothelium from the vessel wall. Although the study is limited to a small number of observations, analytic statistical results suggest that vessel invagination comprises a principal mechanism for bioeffects in venules by microbubbles.
Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA.
Hong
H
Chen
Andrew A
AA
Brayman
Andrew P
AP
Evan
Thomas J
TJ
Matula
D000818:Animals; D003287:Contrast Media; D008297:Male; D008643:Mesentery / Q000098:blood supply*; D045423:Microbubbles; D046529:Microscopy, Electron, Transmission; D055806:Microvessels / Q000000981:diagnostic imaging* / Q000648:ultrastructure; D011312:Pressure; D051381:Rats; D011916:Rats, Inbred F344; D014463:Ultrasonography
D003287:Contrast Media