Ex Vivo Porcine Arterial and Chorioallantoic Membrane Acoustic Angiography Using Dual-Frequency Intravascular Ultrasound Probes.
The presence of blood vessels within a developing atherosclerotic plaque has been found to be correlated with increased plaque vulnerability and ensuing cardiac events, however, detection of coronary intraplaque neovascularization poses a significant challenge in the clinic. We describe here a new in vivo intravascular ultrasound imaging method using a dual-frequency transducer to visualize contrast flow in microvessels with high specificity. This method uses a specialized transducer capable of exciting contrast agents at a low frequency (5.5 MHz) while detecting their nonlinear superhamonics at a much higher frequency (37 MHz). In vitro evaluation of the approach was performed in a microvascular phantom to produce 3-D renderings of simulated vessel patterns and to determine image quality metrics as a function of depth. Furthermore, we describe the ability of the system to detect microvessels both ex vivo using porcine arteries and in vivo using the chorioallantoic membrane of a developing chicken embryo with optical confirmation. Dual-frequency contrast-specific imaging was able to resolve vessels similar in size to those found in vulnerable atherosclerotic plaques at clinically relevant depths. The results of this study add to the support for further evaluation and translation of contrast-specific imaging in intravascular ultrasound for the detection of vulnerable plaques in atherosclerosis.
Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
K Heath
KH
Martin
Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
Brooks D
BD
Lindsey
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA.
Jianguo
J
Ma
Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.
Timothy C
TC
Nichols
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA.
Xiaoning
X
Jiang
Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA; Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, North Carolina, USA. Electronic address: padayton@email.unc.edu.
Paul A
PA
Dayton
D000792:Angiography / Q000379:methods*; D000818:Animals; D001158:Arteries / Q000000981:diagnostic imaging*; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D003287:Contrast Media; D007089:Image Enhancement / Q000379:methods; D055806:Microvessels / Q000000981:diagnostic imaging*; D023421:Models, Animal; D008954:Models, Biological; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D013552:Swine; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000379:methods*
D003287:Contrast Media
Acoustic angiography; Atherosclerosis; Contrast; Dual frequency; Intravascular ultrasound; Microbubble; Superharmonic; Ultrasonography; Vasa vasorum