Multiple-frequency ultrasonic imaging by transmitting pulsed waves of two frequencies.

Purpose: The aim of this study was realization of a broadband measurement system that is capable of effectively carrying out a frequency compound method. In the present method, the secondary wave components of difference and sum frequencies are generated along with the higher harmonic components through the nonlinear interaction of two-frequency ultrasound. A multiple-frequency beam is generated together with the initially radiated frequency components.

Development of an ultra-broadband ultrasonic imaging system: prototype mechanical sector device.

Purpose: We constructed an ultra-broadband ultrasonic transducer in a mechanical sector device, and prototyped a system to generate real-time images with higher harmonics. The potential of the system to reduce speckle was also studied.

Methods: To efficiently detect the higher harmonic components in echo signals, in addition to the transmitting transducer, another transducer only for broadband reception is necessary.

Enhancement of stents using interference of low-frequency ultrasonic echo signals.

Purpose: We set out to enhance the imaging of stents used for coronary coarctation surgery without imaging the reticulation of the stent. Because the stent is a reticulated structure, there is a relation between ultrasound wavelength and the interstice reticulation that produces the echo.

Methods: First we performed computer simulation by ultrasound frequency of transmitted signals to analyze this relation.