title: A PDE-Based Regularization Algorithm Toward Reducing Speckle Tracking Noise: A Feasibility Study for Ultrasound Breast Elastography.
abstract: Obtaining accurate ultrasonically estimated displacements along both axial (parallel to the acoustic beam) and lateral (perpendicular to the beam) directions is an important task for various clinical elastography applications (e.g., modulus reconstruction and temperature imaging). In this study, a partial differential equation (PDE)-based regularization algorithm was proposed to enhance motion tracking accuracy. More specifically, the proposed PDE-based algorithm, utilizing two-dimensional (2D) displacement estimates from a conventional elastography system, attempted to iteratively reduce noise contained in the original displacement estimates by mathematical regularization. In this study, tissue incompressibility was the physical constraint used by the above-mentioned mathematical regularization. This proposed algorithm was tested using computer-simulated data, a tissue-mimicking phantom, and in vivo breast lesion data. Computer simulation results demonstrated that the method significantly improved the accuracy of lateral tracking (e.g., a factor of 17 at 0.5% compression). From in vivo breast lesion data investigated, we have found that, as compared with the conventional method, higher quality axial and lateral strain images (e.g., at least 78% improvements among the estimated contrast-to-noise ratios of lateral strain images) were obtained. Our initial results demonstrated that this conceptually and computationally simple method could be useful for improving the image quality of ultrasound elastography with current clinical equipment as a post-processing tool.
authors.affiliation: School of Mathematical Sciences, University of Science and Technology of China, Hefei, China Department of Mathematical Sciences, Michigan Technological University, Houghton, MI, USA Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Guo
authors.affiliation: School of Mathematical Sciences, University of Science and Technology of China, Hefei, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Mathematical Sciences, Michigan Technological University, Houghton, MI, USA.
authors.forename: Zhengfu
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA jjiang1@mtu.edu.
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Jiang
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D054459:Elasticity Imaging Techniques; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D016217:Ultrasonography, Mammary
keywords: de-noising; elastography; speckle tracking; strain imaging; ultrasound