Dual-frequency piezoelectric transducers for contrast enhanced ultrasound imaging.
For many years, ultrasound has provided clinicians with an affordable and effective imaging tool for applications ranging from cardiology to obstetrics. Development of microbubble contrast agents over the past several decades has enabled ultrasound to distinguish between blood flow and surrounding tissue. Current clinical practices using microbubble contrast agents rely heavily on user training to evaluate degree of localized perfusion. Advances in separating the signals produced from contrast agents versus surrounding tissue backscatter provide unique opportunities for specialized sensors designed to image microbubbles with higher signal to noise and resolution than previously possible. In this review article, we describe the background principles and recent developments of ultrasound transducer technology for receiving signals produced by contrast agents while rejecting signals arising from soft tissue. This approach relies on transmitting at a low-frequency and receiving microbubble harmonic signals at frequencies many times higher than the transmitted frequency. Design and fabrication of dual-frequency transducers and the extension of recent developments in transducer technology for dual-frequency harmonic imaging are discussed.
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University at Raleigh, Chapel Hill, NC 27599, USA. khmartin@ncsu.edu.
K Heath
KH
Martin
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University at Raleigh, Chapel Hill, NC 27599, USA. brooks.lindsey@unc.edu.
Brooks D
BD
Lindsey
Department of Mechanical & Aero-Space Engineering, North Carolina State University, Raleigh, NC 27695, USA. jma9@ncsu.edu.
Jianguo
J
Ma
Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada. hlee@sri.utoronto.ca.
Mike
M
Lee
Department of Mechanical & Aero-Space Engineering, North Carolina State University, Raleigh, NC 27695, USA. sli26@ncsu.edu.
Sibo
S
Li
Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada. stuart@sri.utoronto.ca.
F Stuart
FS
Foster
Department of Mechanical & Aero-Space Engineering, North Carolina State University, Raleigh, NC 27695, USA. xjiang5@ncsu.edu.
Xiaoning
X
Jiang
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University at Raleigh, Chapel Hill, NC 27599, USA. padayton@email.unc.edu.
Paul A
PA
Dayton
D000401:Aircraft / Q000295:instrumentation*; D003287:Contrast Media; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D008422:Materials Testing / Q000295:instrumentation*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008904:Miniaturization; D011846:Radio Waves; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*
D003287:Contrast Media