Title :
Blood noise reduction in intravascular ultrasound imaging
Author :
Gronningsaeter, A. ; Angelsen, B.A.J. ; Gresli, A. ; Torp, Hans G.
Author_Institution :
Dept. of Biomed. Eng., Trondheim Univ., Norway
fDate :
3/1/1995 12:00:00 AM
Abstract :
Scattering from red blood cells (blood noise) increases significantly as the ultrasound frequency is increased above 10 MHz. This reduces the contrast between the vessel wall and the lumen in intravascular ultrasound imaging which makes it difficult to localize the vessel wall and plaque. A blood noise filter based on beam tilting and digital lateral low pass filtering is described. Beam tilting introduces a Doppler shift from blood which results in a frequency separation of the vessel wall signal and the blood noise. The performance of the filter is investigated by simulations and by in vitro experiments. The filter is found to be effective for blood velocities exceeding approximately 50 cm s/sup -1/ at a 20 MHz ultrasound frequency with a beam tilt angle of 10 degrees and a frame rate of 15 f.p.s. By increasing the system frequency to 40 MHz, increase the beam tilt angle to 15 degrees and reduce the frame rate to 10 f.p.s., the filter is effective for blood velocities below 10 cm s/sup -1/.<>
Keywords :
acoustic noise; biomedical ultrasonics; blood; medical image processing; 10 to 40 MHz; Doppler shift; beam tilting; blood noise filter; blood noise reduction; digital lateral low pass filtering; frequency separation; intravascular ultrasound imaging; lumen; medical diagnostic imaging; plaque; red blood cells scattering; vessel wall signal; Digital filters; Doppler shift; Filtering; Frequency; In vitro; Low pass filters; Noise reduction; Red blood cells; Scattering; Ultrasonic imaging;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on