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Journal of Medical Ultrasonics

, Volume 43, Issue 1, pp 19–27 | Cite as

Enhancing effect of phase coherence factor for improvement of spatial resolution in ultrasonic imaging

  • Hideyuki HasegawaEmail author
Original Article

Abstract

Purpose

Spatial resolution is one of the important factors that determines ultrasound image quality. In the present study, methods using the phase variance of ultrasonic echoes received by individual transducer elements have been examined for improvement of spatial resolution.

Method

An imaging method, i.e., phase coherence imaging, which uses the phase coherence factor (PCF) obtained from the phase variance of received ultrasonic echoes, was recently proposed. Spatial resolution is improved by weighting ultrasonic RF signals obtained by delay-and-sum (DAS) beam forming using PCF. In the present study, alternative PCFs, i.e., exponential PCF, harmonic PCF, and Gaussian PCF, have been proposed and examined for further improvement of spatial resolution.

Result

Spatial resolutions realized by the proposed PCFs were evaluated by an experiment using a phantom. The full widths at half maxima of the lateral profiles of an echo from a string phantom were 2.61 mm (DAS only), 1.46 mm (conventional PCF), and 0.48–0.62 mm (proposed PCFs).

Conclusion

The PCFs newly proposed in the present study showed better spatial resolutions than the conventional PCF. The proposed PCFs also realized better visualization of echoes from a diffuse scattering medium than the conventional PCF.

Keywords

Phase variance Coherence factor Spatial resolution Ultrasonic image 

Notes

Acknowledgments

This study was supported by JSPS KAKENHI Grant Number 26289123.

Compliance with ethical standards

Ethical considerations

Animal and human subjects were not used in this study.

Conflict of interest

None.

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Copyright information

© The Japan Society of Ultrasonics in Medicine 2015

Authors and Affiliations

  1. 1.Graduate School of Science and Engineering for ResearchUniversity of ToyamaToyamaJapan

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