The underlying hypothesis in this work is that cross-sectional images (elastograms) which are related to the local bulk Young's moduli of soft tissue [Ophir et al, 1991] convey new information which could substantially increase the capability to display and interpret tissue structure in corresponding conventional sonograms. In order to test this hypothesis, we propose the following specific aims: (1) Investigate the factors and tradeoffs which influence the sensitivity, dynamic range, resolution and signal-to-noise ratio performance of elastograms. (2) Identify and investigate the origin of artifacts which may be present in elastograms. (3) Generate elastograms of tissue mimicking phantoms and of normal bovine muscle in vitro. Compare the elastographically derived elasticity values to elasticity values obtained independently. (4) Compare the sonographic and elastographic visualization of tissue structures in bovine kidneys and human prostates in vitro. Preliminary work has shown that (1) there is a measurable range of elasticities associated with normal tissues (and presumably also with pathological tissues); (2) elastography is capable of producing elasticity based images (elastograms), which are of sufficient resolution and sensitivity to visualize the complex elastic structure of heterogeneous soft tissues in vivo; and (3) the structural information of tissue displayed by elastography may not be otherwise obtainable. The work proposed here is intended to provide answers to some fundamental questions; these questions pertain to all aspects of elastography, starting from the basic physics, through signal processing and optimization, and ending in image formation and interpretation. The answers are expected to put elastography on a firm theoretical and experimental foundation, thereby allowing expansion of the capabilities of diagnostic ultrasound imaging.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA060520-01
Application #
3204037
Study Section
Diagnostic Radiology Study Section (RNM)
Project Start
1993-09-01
Project End
1996-08-31
Budget Start
1993-09-01
Budget End
1994-08-31
Support Year
1
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Texas Health Science Center Houston
Department
Type
Schools of Medicine
DUNS #
City
Houston
State
TX
Country
United States
Zip Code
77225
Ophir, J; Alam, S K; Garra, B et al. (1999) Elastography: ultrasonic estimation and imaging of the elastic properties of tissues. Proc Inst Mech Eng H 213:203-33
Varghese, T; Ophir, J (1999) A method for experimental characterization of the noise performance of elastographic systems. Ultrason Imaging 21:17-30
Stafford, R J; Kallel, F; Price, R E et al. (1998) Elastographic imaging of thermal lesions in soft tissue: a preliminary study in vitro. Ultrasound Med Biol 24:1449-58
Kallel, F; Ophir, J (1998) Limits on the contrast of strain concentrations in elastography. Ultrasound Med Biol 24:1215-9
Varghese, T; Ophir, J (1998) An analysis of elastographic contrast-to-noise ratio. Ultrasound Med Biol 24:915-24
Kallel, F; Ophir, J; Magee, K et al. (1998) Elastographic imaging of low-contrast elastic modulus distributions in tissue. Ultrasound Med Biol 24:409-25
Varghese, T; Ophir, J (1998) Characterization of elastographic noise using the envelope of echo signals. Ultrasound Med Biol 24:543-55
Konofagou, E E; Ophir, J; Kallel, F et al. (1997) Elastographic dynamic range expansion using variable applied strains. Ultrason Imaging 19:145-66
Kallel, F; Ophir, J (1997) A least-squares strain estimator for elastography. Ultrason Imaging 19:195-208
Kallel, F; Varghese, T; Ophir, J et al. (1997) The nonstationary strain filter in elastography: Part II. Lateral and elevational decorrelation. Ultrasound Med Biol 23:1357-69

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