Enhancement of stents using interference of low-frequency ultrasonic echo signals.
OBJECTIVE
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. Then, instead of controlling the transmitted wave, we processed the returned signals through a band-pass filter because of the difficulty of controlling the transmitted waves of diagnostic ultrasound equipment. Following this, we conducted experiments on an agar gel phantom containing a stent to verify the effectiveness of this method.


RESULTS
The simulation confirmed that the stent was apparent when the ultrasonic wavelength equaled the product of an integer and twice the interval of the reticulation of the stent. Application of a band-pass filter of 0.8 to 1.5 MHz to the waveform returned from the agar gel phantom containing the stent.


CONCLUSIONS
The effectiveness of this method in depicting the stent was confirmed.
Faculty of Engineering Shizuoka University, Hamamatsu, Japan. ohashi@ece.ucsb.edu.
Gosuke
G
Ohashi
Institute of Information Sciences and Electronics University of Tsukuba, Tsukuba, Japan.
Akihisa
A
Ohya
Shoryo Electronic Corporation, Kamakura, Japan.
Kazunobu
K
Tobise
Faculty of Engineering Shonan Institute of Technology, Fujisawa, Japan.
Iwaki
I
Akiyama
interference; received waveform; signal processing; stent; ultrasonic echography