Noise Performance and Signal-to-Noise Ratio of Shear Strain Elastograms

In this paper, we develop a theoretical expression for the signal-to-noise ratio (SNR) of shear strain elastograms. The previously-developed ideas for the axial strain filter (ASF) and lateral strain filter (LSF) are extended to define the concept of the shear strain filter (SSF). Some of our theoretical results are verified using simulations and phantom experiments. The results indicate that the signal-to-noise ratio of shear-strain elastograms (SNR sse) improves with increasing shear strain and with improvements in system parameters such as the sonographic signal-to-noise ratio (SNR s) beamwidth, center frequency and fractional bandwidth. The results also indicate that the amount of axial strain present along with the shear strain is an important parameter that determines the upper bound on SNR sse. The SNR sse will be higher in the absence of additional deformation due to axial strain.

[1]  T. Varghese,et al.  A theoretical framework for performance characterization of elastography: the strain filter , 1997, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[2]  Faouzi Kallel,et al.  Elastography: A systems approach , 1997, Int. J. Imaging Syst. Technol..

[3]  G.E. Trahey,et al.  A comparative evaluation of several algorithms for phase aberration correction , 1994, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[4]  K. R. Raghavan,et al.  Lateral displacement estimation using tissue incompressibility , 1996, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[5]  B. Garra,et al.  Elastography: Ultrasonic imaging of tissue strain and elastic modulus in vivo , 1996 .

[6]  Tsuyoshi Shiina,et al.  Real time tissue elasticity imaging using the combined autocorrelation method , 2002, Journal of Medical Ultrasonics.

[7]  B G Zagar,et al.  Ultrasonic mapping of the microvasculature: signal alignment. , 1998, Ultrasound in medicine & biology.

[8]  R. Righetti,et al.  Trade-offs between the axial resolution and the signal-to-noise ratio in elastography. , 2003 .

[9]  Timothy J. Hall,et al.  In vivo results of real-time freehand elasticity imaging , 2001, 2001 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.01CH37263).

[10]  M. O’Donnell,et al.  Theoretical analysis and verification of ultrasound displacement and strain imaging , 1994, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[11]  B. Garra,et al.  Elastography of breast lesions: initial clinical results. , 1997, Radiology.

[12]  Michel Bertrand,et al.  Ultrasonic texture motion analysis: theory and simulation , 1995, IEEE Trans. Medical Imaging.

[13]  J. Ophir,et al.  A new elastographic method for estimation and imaging of lateral displacements, lateral strains, corrected axial strains and Poisson's ratios in tissues. , 1998, Ultrasound in medicine & biology.

[14]  W. Walker,et al.  A fundamental limit on delay estimation using partially correlated speckle signals , 1995, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[15]  J. Ophir,et al.  The combined effect of signal decorrelation and random noise on the variance of time delay estimation , 1997, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[16]  R. F. Wagner,et al.  Statistics of Speckle in Ultrasound B-Scans , 1983, IEEE Transactions on Sonics and Ultrasonics.

[17]  J. Ophir,et al.  Three-dimensional tissue motion and its effect on image noise in elastography , 1997, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[18]  J. Meunier,et al.  Echographic image mean gray level changes with tissue dynamics: a system-based model study , 1995, IEEE Transactions on Biomedical Engineering.

[19]  J. Ophir,et al.  Methods for Estimation of Subsample Time Delays of Digitized Echo Signals , 1995 .

[20]  J. Ophir,et al.  Reduction of Image Noise in Elastography , 1993 .

[21]  S Hsueh,et al.  Analysis of sonographic features for the differentiation of benign and malignant breast tumors of different sizes , 2004, Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology.

[22]  J. Ophir,et al.  Elastography: A Quantitative Method for Imaging the Elasticity of Biological Tissues , 1991, Ultrasonic imaging.

[23]  J. Ophir,et al.  Theoretical bounds on strain estimation in elastography , 1995, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[24]  A. Stavros,et al.  Solid breast nodules: use of sonography to distinguish between benign and malignant lesions. , 1995, Radiology.

[25]  J Ophir,et al.  Shear strain estimation and lesion mobility assessment in elastography. , 2000, Ultrasonics.

[26]  T. Krouskop,et al.  Elastography: Ultrasonic estimation and imaging of the elastic properties of tissues , 1999, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[27]  Tomy Varghese,et al.  Estimation of displacement vectors and strain tensors in elastography using angular insonifications , 2004 .

[28]  W. Walker,et al.  A fundamental limit on the performance of correlation based phase correction and flow estimation techniques , 1994, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[29]  M. O’Donnell,et al.  Internal displacement and strain imaging using ultrasonic speckle tracking , 1994, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[30]  Raoul Mallart,et al.  The van Cittert–Zernike theorem in pulse echo measurements , 1991 .

[31]  T. Wonnacott,et al.  Introductory statistics for business and economics , 1972 .

[32]  F. Kallel,et al.  Elastography: A systems approach , 1997, Int. J. Imaging Syst. Technol..

[33]  Jonathan Ophir,et al.  Comparing elastographic strain images with modulus images obtained using nanoindentation: preliminary results using phantoms and tissue samples. , 2004, Ultrasound in medicine & biology.

[34]  T. Varghese,et al.  Enhancement of echo-signal correlation in elastography using temporal stretching , 1997, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[35]  P L Carson,et al.  Ultrasound tissue displacement imaging with application to breast cancer. , 1995, Ultrasound in medicine & biology.

[36]  Mb Popli.  Pictorial essay : Sonographic differentiation of solid breast lesions , 2002 .