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Harmonic motion is produced in a subject using vibro-acoustography. An ultrasonic imaging system repetitively interrogates the subject and the Doppler shift in the reflected echo signals is analyzed to measure the phase and amplitude of harmonic motion produced in the subject at different prescribed frequencies. Shear wave propagation through the subject is determined from this information and mechanical properties related to “stiffness” of the subject are determined. A Kalman filter is employed in the phase and amplitude measurement to extract the harmonic motion information from background noise.

Patent No.: US 7,785,259

Date of Patent: Aug. 31, 2010

Filed: Oct 1, 2004

Int. Cl.: A61B 8/00 (2006-01)

U.S. Cl.: 600/438; 600/441; 600/442; 600/ 444; 601/2; 606/128; 73/1-82; 73/1-89

CPC Cl.: A61B 5/0048 (2013.01); A61B 8/485 (2013.01); A61B 8/00 (2013.01)

Field of Search: 600/437, 600/438, 441, 444, 442; 601/2; 606/128; 73/1 .82, 1.89


Also online at US 7785259.



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