Efficient Strategies for Estimating the Spatial Coherence of Backscatter

The spatial coherence of ultrasound backscatter has been proposed to reduce clutter in medical imaging, to measure the anisotropy of the scattering source, and to improve the detection of blood flow. These techniques rely on correlation estimates that are obtained using computationally expensive strategies. In this paper, we assess the existing spatial coherence estimation methods and propose three computationally efficient modifications: a reduced kernel, a downsampled receive aperture, and the use of an ensemble correlation coefficient. The proposed methods are implemented in simulation and in vivo studies. Reducing the kernel to a single sample improved computational throughput and improved axial resolution. Downsampling the receive aperture was found to have negligible effect on estimator variance, and improved computational throughput by an order of magnitude for a downsample factor of 4. The ensemble correlation estimator demonstrated lower variance than the currently used average correlation. Combining the three methods, the throughput was improved 105-fold in simulation with a downsample factor of 4- and 20-fold in vivo with a downsample factor of 2.

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

[2]  Pai-Chi Li,et al.  Transform-Based Channel-Data Compression to Improve the Performance of a Real-Time GPU-Based Software Beamformer , 2016, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[3]  J. Walkup,et al.  Statistical optics , 1986, IEEE Journal of Quantum Electronics.

[4]  Mickael Tanter,et al.  Ultrasound backscatter tensor imaging (BTI): analysis of the spatial coherence of ultrasonic speckle in anisotropic soft tissues , 2014, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[5]  M O'Donnell,et al.  Phase Aberration Measurements in Medical Ultrasound: Human Studies , 1988, Ultrasonic imaging.

[6]  Sverre Holm,et al.  Implementing capon beamforming on a GPU for real-time cardiac ultrasound imaging , 2014, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

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

[8]  Gregg E Trahey,et al.  In vivo application of short-lag spatial coherence imaging in human liver. , 2013, Ultrasound in medicine & biology.

[9]  G. Trahey,et al.  Short-lag spatial coherence imaging of cardiac ultrasound data: initial clinical results. , 2013, Ultrasound in medicine & biology.

[10]  Gianmarco Pinton,et al.  Spatial coherence in human tissue: implications for imaging and measurement , 2014, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[11]  Gregg E. Trahey,et al.  Performance evaluation of combined spatial compounding-adaptive imaging: simulation, phantom and clinical trials , 2003, IEEE Symposium on Ultrasonics, 2003.

[12]  Dongwoon Hyun,et al.  Short-lag spatial coherence imaging on matrix arrays, Part 1: Beamforming methods and simulation studies , 2014, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[13]  J.G. Miller,et al.  Spatial coherence of backscatter for the nonlinearly produced second harmonic for specific transmit apodizations , 2004, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[14]  S.W. Smith,et al.  Comparison of 3-D multi-lag cross- correlation and speckle brightness aberration correction algorithms on static and moving targets , 2009, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[15]  G E Trahey,et al.  Speckle coherence and implications for adaptive imaging. , 1997, The Journal of the Acoustical Society of America.

[16]  A. Austeng,et al.  Adaptive Beamforming Applied to Medical Ultrasound Imaging , 2007, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[17]  R. Fisher.  014: On the "Probable Error" of a Coefficient of Correlation Deduced from a Small Sample. , 1921 .

[18]  J.T. Powers,et al.  An axial velocity estimator for ultrasound blood flow imaging, based on a full evaluation of the Doppler equation by means of a two-dimensional autocorrelation approach , 1995, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[19]  M. O’Donnell,et al.  Phase-aberration correction using signals from point reflectors and diffuse scatterers: basic principles , 1988, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[20]  Gregg E. Trahey,et al.  Quantitative Assessment of the Magnitude, Impact and Spatial Extent of Ultrasonic Clutter , 2008, Ultrasonic imaging.

[21]  R. F. Wagner,et al.  Ultrasound speckle size and lesion signal to noise ratio: verification of theory. , 1984, Ultrasonic imaging.

[22]  Dongwoon Hyun,et al.  Lesion Detectability in Diagnostic Ultrasound with Short-Lag Spatial Coherence Imaging , 2011, Ultrasonic imaging.

[23]  You Leo Li,et al.  Coherent flow power doppler (CFPD): flow detection using spatial coherence beamforming , 2015, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[24]  G. Carter.  Coherence and time delay estimation , 1987, Proceedings of the IEEE.

[25]  G E Trahey,et al.  A Quantitative Approach to Speckle Reduction via Frequency Compounding , 1986, Ultrasonic imaging.

[26]  B. Savord,et al.  Fully sampled matrix transducer for real time 3D ultrasonic imaging , 2003, IEEE Symposium on Ultrasonics, 2003.

[27]  B. Y. S. Yiu,et al.  GPU-based beamformer: Fast realization of plane wave compounding and synthetic aperture imaging , 2011, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[28]  G. E. Trahey,et al.  Short-lag spatial coherence of backscattered echoes: imaging characteristics , 2011, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[29]  C. Burckhardt.  Speckle in ultrasound B-mode scans , 1978, IEEE Transactions on Sonics and Ultrasonics.

[30]  Pai-Chi Li,et al.  Adaptive imaging using the generalized coherence factor. , 2003, IEEE transactions on ultrasonics, ferroelectrics, and frequency control.

[31]  Hiroshi Kanai,et al.  Effect of subaperture beamforming on phase coherence imaging , 2014, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[32]  Dongwoon Hyun,et al.  A GPU-based real-time spatial coherence imaging system , 2013, Medical Imaging.

[33]  J.G. Miller,et al.  Spatial coherence of the nonlinearly generated second harmonic portion of backscatter for a clinical imaging system , 2003, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

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

[35]  J. Arendt.  Paper presented at the 10th Nordic-Baltic Conference on Biomedical Imaging: Field: A Program for Simulating Ultrasound Systems , 1996 .

[36]  K. Boone,et al.  Effect of skin impedance on image quality and variability in electrical impedance tomography: a model study , 1996, Medical and Biological Engineering and Computing.

[37]  C. Kasai,et al.  Real-Time Two-Dimensional Blood Flow Imaging Using an Autocorrelation Technique , 1985, IEEE 1985 Ultrasonics Symposium.

[38]  J. Camacho,et al.  Phase Coherence Imaging , 2009, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[39]  Gregg E Trahey,et al.  Sources of image degradation in fundamental and harmonic ultrasound imaging: a nonlinear, full-wave, simulation study. , 2011, IEEE transactions on ultrasonics, ferroelectrics, and frequency control.