Conventional techniques in elastography estimate the axial strain as the gradient of the displacement (time-delay) estimates obtained using cross-correlation of pre- and temporally stretched postcompression radiofrequency (RF) A-line segments. The use of a constant stretch factor for stretching the postcompression A-line is not adequate in the presence of heterogeneous targets that are commonly...

Ethanol-induced hepatic lesions were investigated in swine for in vivo use as a strain imaging animal model. Lesions (n = 25) were induced by injecting ethanol (doses 0.33 to 2.0 mL) directly into the surgically exposed liver at depths of 12, 15 or 25 mm. Lesions were imaged with a modified HDI 1000 scanner (Philips Medical Systems, Bothell, WA, USA). The elastograms (n = 91) characterized lesi...

AIM To optimise the method of real-time elastography (RTE) in the assessment of liver fibrosis using an in-house prepared method for elastogram analysis, as well as a semiquantitative analysis based on newly introduced parameters. MATERIAL AND METHODS Sonoelastography was performed in 94 patients with various degrees of liver fibrosis and also in 25 healthy volunteers. As a reference method f...

In elastography, the tissue under investigation is compressed and the resulting strain is estimated from the gradient of the displacement (time-delay) estimates. The displacements are typically estimated by crosscorrelating the radiofrequency (RF) ultrasound signals of the preand postcompressed tissue. One of the parameters used to quantify the resulting quality of the elastogram is the elastog...

Elastography is based on the estimation of strain due to tissue compression or expansion. Conventional elastography involves computing strain as the gradient of the displacement (time-delay) estimates between gated pre- and postcompression signals. Uniform temporal stretching of the postcompression signals has been used to reduce the echo-signal decorrelation noise. However, a uniform stretch o...

Spatial-angular compounding is a new technique developed for improving the signal-to-noise ratio (SNR) in elastography. Under this method, elastograms of a region-of-interest (ROI) are obtained from a spatially weighted average of local strain estimated along different insonification angles. In this article, we investigate the improvements in the strain contrast and contrast-to-noise ratio (CNR...

INTRODUCTION Magnetic resonance elastography (MRE) is a phase-contrast technique that can noninvasively visualize shear waves patterns within tissue [1]. Accurate values of tissue stiffness are calculated by the equations of motion from the shear wave pattern of a single frequency [2]. In order to generate shear waves within tissue, various external drivers have been proposed [3]. To acquire an...

Problem statement: Elastography is developed as a quantitative approach to imaging linear elastic properties of tissues to detect suspicious tumors. We propose an automatic feature extraction method in ultrasound elastography and echography for characterization of breast lesions. Approach: The proposed algorithm was tested on 40 pairs of biopsy proven ultrasound elastography and echography imag...

Brain tumour resection requires the surgeon to evaluate mechanical properties such as tumour stiffness and adherence o f tumour to the surrounding normal brain. This is a subjective assessment. Ultrasound elasticity imaging techniques allow more objective measurement and imaging o f mechanical properties such as strain, which is related to stiffness, in the case o f ultrasound elastography. Thi...

This paper presents the tradeoffs in elastographic imaging. Elastography is viewed as a new imaging modality and presented in terms of three fundamental concepts that constitute the basis for the elastographic imaging process. These are the tissue elastic deformation process, the statistical analysis of strain estimation and the image characterization. The first concept involves the use of the ...