? The current practice of elastography, images only the axial component of the strain tensor, while the lateral and elevational strain tensor components are basically disregarded. In the absence of lateral and elevational components, other important elastic parameters such as shear strains and Poisson's are not imaged. Moreover, efforts at reconstruction of the Young's modulus from strain data would be significantly improved if all the normal and shear strain tensors are available. In this research, we propose a novel method of estimating displacements and strains in axial, lateral and elevational directions in ultrasound elastography imaging. The method uses tissue displacement components estimated along multiple angular ultrasound beam directions acquired with linear array transducers. Strain elastograms of normal and shear tensors are then calculated from the axial and lateral displacement information in addition to Poisson's ratio information. ? ? The research plan develops and optimizes this method for a state-of-the-art scanner using simulations to evaluate tradeoffs between acquisition rate, angles and data accuracy. Implementation of the techniques will be on the Siemens Antares scanner, capitalizing on a newly developed ultrasound research interface to facilitate angular beam data acquisition and control. Tests using elastography phantoms will yield performance benchmarks. Two new phantom types will also be developed to evaluate the ability to derive the fundamental information expected in these images. Finally, excised tissue samples will be imaged to evaluate the new elasticity information obtained. ? ? Clinical applications where the methodology will be directed are in differentiating malignant from benign masses in the breast and thyroid. In both sites lateral slippage is believed to occur in many benign masses when the tissue is compressed, while slippage appears to be absent with malignant masses. The proposed lateral and shear strain images are expected to be particularly sensitive to such phenomena. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21EB003853-03
Application #
7102801
Study Section
Special Emphasis Panel (ZRR1-BT-5 (01))
Program Officer
Lopez, Hector
Project Start
2004-08-16
Project End
2007-07-31
Budget Start
2006-08-01
Budget End
2007-07-31
Support Year
3
Fiscal Year
2006
Total Cost
$172,320
Indirect Cost
Name
University of Wisconsin Madison
Department
Physics
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Omari, Eenas; Lee, Heichang; Varghese, Tomy (2011) Theoretical and phantom based investigation of the impact of sound speed and backscatter variations on attenuation slope estimation. Ultrasonics 51:758-67
Xu, Haiyan; Rao, Min; Varghese, Tomy et al. (2010) Axial-shear strain imaging for differentiating benign and malignant breast masses. Ultrasound Med Biol 36:1813-24
Shi, Hairong; Varghese, Tomy; Mitchell, Carol C et al. (2009) In vivo attenuation and equivalent scatterer size parameters for atherosclerotic carotid plaque: preliminary results. Ultrasonics 49:779-85
Rao, Min; Varghese, Tomy; Madsen, Ernest L (2008) Shear strain imaging using shear deformations. Med Phys 35:412-23
Shi, Hairong; Varghese, Tomy; Dempsey, Robert J et al. (2008) Relationship between ultrasonic attenuation, size and axial strain parameters for ex vivo atherosclerotic carotid plaque. Ultrasound Med Biol 34:1666-77
Chen, Hao; Varghese, Tomy (2008) Noise analysis and improvement of displacement vector estimation from angular displacements. Med Phys 35:2007-17
Shi, Hairong; Mitchell, Carol C; McCormick, Matthew et al. (2008) Preliminary in vivo atherosclerotic carotid plaque characterization using the accumulated axial strain and relative lateral shift strain indices. Phys Med Biol 53:6377-94
Rao, M; Chen, Q; Shi, H et al. (2007) Normal and shear strain estimation using beam steering on linear-array transducers. Ultrasound Med Biol 33:57-66
Rao, Min; Varghese, Tomy (2007) Correlation analysis for angular compounding in strain imaging. IEEE Trans Ultrason Ferroelectr Freq Control 54:1903-7
Chen, Hao; Shi, Hairong; Varghese, Tomy (2007) Improvement of elastographic displacement estimation using a two-step cross-correlation method. Ultrasound Med Biol 33:48-56

Showing the most recent 10 out of 22 publications