Prolonging the ultrasound signal enhancement from thrombi using targeted microbubbles based on sulfur-hexafluoride-filled gas.
OBJECTIVE
The objective of this study is to develop and characterize new microbubbles based on lipids and sulfur hexafluoride (SF6) for targeting thrombi as an improved ultrasound contrast agent.


METHODS
Bioconjugate ligands were inserted into the lipid-coated membranes of SF6 gas microbubbles, and their physicochemical properties were determined. Diagnostic efficacies of SF6-filled microbubbles and the contrast agent SonoVue (Bracco Imaging, Geneve, Switzerland) were compared in dogs.


RESULTS
Suspensions of lyophilized powder were reconstituted by injecting saline containing 3.1 x 10(8) SF6 microbubbles/mL with a mean diameter of 4.4 microm. More than 90% of microbubbles had diameters between 1 and 10 microm. After reconstitution, echogenicity and microbubble characteristics were unchanged for 8 hours. Targeted microbubbles increased the echogenicity of thrombi significantly and provided a longer period of optimal signal enhancement compared with nontargeted microbubbles.


CONCLUSIONS
Our thrombus-targeting microbubble contrast agent shows high echogenicity and stability and thereby enhances the visualization of intravascular thrombi and prolongs the duration of the diagnostic window.
Department of Pathology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
Bing
B
Wang
Wei-Jin
WJ
Zang
Mei
M
Wang
Hong
H
Ai
Ya-Wen
YW
Wang
Yi-Ping
YP
Li
Gen-Shan
GS
He
Li
L
Wang
Xiao-Jiang
XJ
Yu
D000818:Animals; D004285:Dogs; D004452:Echocardiography / Q000379:methods*; D005260:Female; D005740:Gases; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D045423:Microbubbles; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride; D020246:Venous Thrombosis / Q000000981:diagnostic imaging*
D005740:Gases; D013459:Sulfur Hexafluoride