Sound speed optimization for ultrasound beamforming using differential phase gradient between sub-apertures

Che Chou Shen, Hsiao Chi Yang, Gency Jeng

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Medical ultrasound imaging systems rely on a presumed sound speed to calculate the delay compensation of each array element for coherent receive focusing. However, due to mismatch between the tissue sound speed (Ctissue) and the beamforming sound speed (Cbeam), the phase coherence across the array is often compromised and the resultant image quality degrades. In order to alleviate the sound speed mismatch, differential phase gradient between sub-apertures is proposed in this study by using channel-domain autocorrelation to estimate the optimal sound speed for beamforming. Simulations of point reflector show that the differential phase gradient approaches zero whenever Cbeam is set to Ctissue. In experiments using speckle phantom, the optimized sound speed is estimated to be 1420 m/s compared to the nominal sound speed of 1450 m/s. The corresponding B-mode images at 7 MHz show that the optimization of sound speed reduces the -12-dB lateral width of point spread function from 0.94 mm to 0.71 mm. The image contrast between cyst and background also peaks near the optimized sound speed. Compared to minimum average phase variance (MAPV) method, the proposed method is more robust by reducing the coefficient of variation from 0.5 % to 0 %.

Original languageEnglish
Title of host publication2016 IEEE International Ultrasonics Symposium, IUS 2016
PublisherIEEE Computer Society
ISBN (Electronic)9781467398978
DOIs
StatePublished - 1 Nov 2016
Event2016 IEEE International Ultrasonics Symposium, IUS 2016 - Tours, France
Duration: 18 Sep 201621 Sep 2016

Publication series

NameIEEE International Ultrasonics Symposium, IUS
Volume2016-November
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727

Conference

Conference2016 IEEE International Ultrasonics Symposium, IUS 2016
CountryFrance
CityTours
Period18/09/1621/09/16

Keywords

  • Channel-domain autocorrelation
  • Differential phase gradient
  • Sound speed optimization

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