High-Frequency Ultrasonic Transducers to Uncover Cardiac Dynamics

Abstract

In order to improve medical ultrasound image resolution, ultrasound imaging is being pushed to higher and higher frequencies. High-frequency (higher than 30 MHz) ultrasound provides a noninvasive imaging method for many clinical and preclinical applications requiring improved spatial resolution. There are a number of clinical problems that may benefit from high-frequency ultrasound imaging. Significant progress in the development of high-frequency single-element and array transducers has been achieved in the past few years. Single-element ultrasound transducers have been exclusively used in high-frequency ultrasound imaging for many years. They have been able to provide an adequate solution in a number of clinical and preclinical applications including small animal imaging. These single-element transducers however are less than ideal due to their single geometrical focus and must be mechanically scanned to form an image. Dynamic focusing is a distinct advantage that array transducers possess over single-element transducers. Array systems use electronic scanning to form an image slice and therefore can achieve higher frame rates. Also, ultrasound beam can be steered and dynamically focused in the image plane. In this chapter, the high-frequency transducer/array for small animal heart imaging will be reported, and pulsed-wave Doppler for blood flow detection will also be discussed.