Fast and Precise Estimation of Displacement and Strain Fields in Elastography Imaging Technique

Mechanical variables and properties of soft tissues, such as strain and Young’s modulus, are estimated by dint of novel methods known as Elastography, for instance, with the aim of improving medical diagnoses, especially the noninvasive detection and classification of tumors. In elastography approach, local mechanical properties of tissues are estimated from their responses to static or dynamic excitations, which are being recorded using conventional medical imaging machines. In the most elastography techniques, for example, strain (static) elastography, displacement fields are generally extracted from the recorded data such as ultrasound images and signals. The profits of cross correlation algorithm, for instance, high precision, accuracy, and resolution, have made it the most prevalent method for estimating strain field in the tissue from the recorded ultrasound signals and images. The benefits of cross correlation method outweigh its defect in the fast computation of displacement and strain field. In this paper, some strategies, specifically the guided search, have been manipulated to improve the speed of algorithm, without decreasing its accuracy. In order to evaluate the proposed stratagem, the ultrasound signals, which had been captured while a cancerous liver was compressing, have been utilized. The average differences between the axial displacement and strain fields estimated by applying the enhanced cross correlation method (calculated in less than 30s) and the analytic minimization technique have been computed 0.22sample and 0.21×10-2. Minor disparities between the two sets of displacement and strain field estimated utilizing the aforementioned techniques validate the accuracy of results of the enhanced cross correlation method.