The progress of the previous four years of this program has been substantial. New beams have been discovered and evaluated, new ceramics have been evaluated, novel arrays have been built and studied, and new methods of aberration correction and flow estimation have been demonstrated. Our goal continues to be to develop new beams for improving the quality of medical ultrasound imaging. In this phase of the research we will develop new approaches to velocity estimation based on signal processing techniques developed in the sonar and radar literature collectively called direction-of-arrival (DOA) methods. Our general hypothesis is: Special transducer geometries (for transmit) combined with special beamforming in receive, derived from DOA concepts, will produce quality improvements in blood and tissue velocity imaging. The hypothesis will be tested through four Aims: 1) High-resolution velocity discrimination. Very high velocity resolution methods are developed from dOA theory; 2) Novel clutter rejection approaches which also ensue from DOA theory; 3) True- velocity flow mapping. Doppler flow-mapping process is described as a convolution of the true velocity map and a generalized ambiguity function; and 4) Quantitative schlieren beam imaging. The Doppler beams will be characterized using a specially modified schlieren system. Successful completion of this collaboration between imaging scientists at Mayo and signal processing experts at the University of Minnesota will result in improved medical ultrasound imaging of tissue and blood motion.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA043920-11
Application #
2894697
Study Section
Special Emphasis Panel (ZRG7-DMG (01))
Program Officer
Menkens, Anne E
Project Start
1987-01-01
Project End
2001-06-30
Budget Start
1999-07-01
Budget End
2001-06-30
Support Year
11
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Mayo Clinic, Rochester
Department
Type
DUNS #
City
Rochester
State
MN
Country
United States
Zip Code
55905
Pitts, T A; Greenleaf, J F (2000) Three-dimensional optical measurement of instantaneous pressure. J Acoust Soc Am 108:2873-83
Dutt, V; Greenleaf, J F (1996) Statistics of the log-compressed echo envelope. J Acoust Soc Am 99:3817-25
Jiang, Z Y; Greenleaf, J F (1996) The nonlinear interaction of two plane waves in a viscous medium. J Acoust Soc Am 99:2783-90
Jiang, Z Y; Greenleaf, J F (1996) Acoustic radiation pressure in a three-dimensional lossy medium. J Acoust Soc Am 100:741-7
Xu, X L; Tewfik, A H; Greenleaf, J F (1995) Time delay estimation using wavelet transform for pulsed-wave ultrasound. Ann Biomed Eng 23:612-21
Dutt, V; Greenleaf, J F (1995) Speckle analysis using signal to noise ratios based on fractional order moments. Ultrason Imaging 17:251-68
Dutt, V; Greenleaf, J F (1994) Ultrasound echo envelope analysis using a homodyned K distribution signal model. Ultrason Imaging 16:265-87
Lu, J Y; Zou, H; Greenleaf, J F (1994) Biomedical ultrasound beam forming. Ultrasound Med Biol 20:403-28
Lu, J Y; Greenleaf, J F (1993) Producing deep depth of field and depth-independent resolution in NDE with limited diffraction beams. Ultrason Imaging 15:134-49
Song, T K; Lu, J; Greenleaf, J F (1993) Modified X waves with improved field properties. Ultrason Imaging 15:36-47

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