Feature-adaptive motion tracking of ultrasound image sequences using a deformable mesh

Abstract

By exploiting the correlation of ultrasound speckle patterns that result from scattering by underlying tissue elements, two-dimensional tissue motion theoretically can be recovered by tracking the apparent movement of the associated speckle patterns. Speckle tracking, however, is an ill-posed inverse problem because of temporal decorrelation of the speckle patterns and the inherent low signal-to-noise ratio of medical ultrasonic images. This paper investigates the use of an adaptive deformable mesh for nonrigid tissue motion recovery from ultrasound images. The nodes connecting the mesh elements are allocated adaptively to stable speckle patterns that are less susceptible to temporal decorrelation. We use the approach of finite element analysis in manipulating the irregular mesh elements. A novel deformable block matching algorithm, making use of a Lagrange element for higher-order description of local motion, is proposed to estimate a nonrigid motion vector at each node. In order to ensure that the motion estimates are admissible to a physically plausible solution, the nodal displacements are regularized by minimizing the strain energy associated with the mesh deformations. Experiments based on ultrasound images of a tissue-mimicking phantom and a muscle undergoing contraction, and on computer simulations, have shown that the proposed algorithm can successfully track nonrigid displacement fields.

Viscoelastic Imaging of Breast Tumor Microenvironment With Ultrasound

“…Either way, the time-varying constitutive equation relating stress σ and strain ε under these quasi-static conditions may be given as σ(t) = G e (t)ε (t), where G e is called the elastic shear modulus. Other investigators apply a stress field that varies sinusoidally over time while tracking movements sonically (28), ultrasonically (29) or with MR methods (30)(31)(32). Steady-state dynamic conditions are assumed to adopt the frequency domain constitutive equation σ(ω) = G * (ω)ε(ω), where G * is the complex shear modulus that depends on the frequency of the stimulus ω. Static and dynamic techniques provide different features of the material properties of tissue, and it is still unknown how each feature describes the tumor microenvironment.…”

Hybrid Formulation of the Model-Based Non-rigid Registration Problem to Improve Accuracy and Robustness

“…In 1998, Yeung [3] showed impressive registration results on a phantom using an energy minimization formulation combining ultrasound speckle tracking with a mechanical finite element model. Rohr et al [4] combined elastic regularization with an improved block matching (BM) algorithm relying on relevant anatomical landmarks and taking into account the anisotropic matching error.…”

Non Invasive Estimation of Left ventricular Normalized Torsion Angle in Healthy Persons by Echo Tracking Algorithm: Short Axis view

“…2D echocardiography was performed using the standard parasternal short axis view according to the guidelines of the American Society of Echocardiography (ASE) (16,17). For each subject, we scanned basal and apical levels in the short axis view using a high-frame-rate (60 frame/s) harmonic B-mode with transmitted and received frequency of 1.7 MHz and 3.4 MHz, respectively.…”

“…In this study, echo tracking in the consecutive frames was estimated by BM algorithm (17,18). In the BM algorithm, given a block of pixels or reference block in the current frame, matching comprises finding the block in the next frames that best matches the block in the reference frame.…”