1988
DOI: 10.1002/jcu.1870160204
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A new method of measuring in vivo sound speed in the reflection mode

Abstract: This paper describes a new method for in vivo sound measurement in the reflection mode. The mean sound speed between the reflector and linear array transducer is measured using the following three parameters: time of flight, time of flight difference, and distance between two receiver elements. To detect time of flight, the system delay-line time compensator is adjusted to obtain the sharpest reflector image. This method was evaluated in vivo in human livers, specifically 26 normal, 27 cirrhotic, and 15 fatty … Show more

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Cited by 37 publications
(11 citation statements)
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“…The average sound-speed estimators include techniques based on the apparent shift from two angles, 19,20 beam tracking, 21 transaxial compression, 22 phase a) Electronic mail: marko.jakovljevic@stanford.edu variance, 23 and echo arrival times at the receive aperture. [24][25][26] These methods have low accuracy in the presence of inhomogeneities, which makes them unsuitable for in vivo measurement through layers of subcutaneous fat and connective tissue. For example, the average SoS estimator by Anderson and Trahey 25 yields highly accurate estimates in homogeneous media (bias less than 0.2% and standard deviation less than 0.52%); however, in a two-layer phantom composed of water and agar-graphite, measured biases in the bottom layer exceeded 30 m/s while the standard deviation was approximately 10 m/s.…”
Section: Introductionmentioning
confidence: 99%
“…The average sound-speed estimators include techniques based on the apparent shift from two angles, 19,20 beam tracking, 21 transaxial compression, 22 phase a) Electronic mail: marko.jakovljevic@stanford.edu variance, 23 and echo arrival times at the receive aperture. [24][25][26] These methods have low accuracy in the presence of inhomogeneities, which makes them unsuitable for in vivo measurement through layers of subcutaneous fat and connective tissue. For example, the average SoS estimator by Anderson and Trahey 25 yields highly accurate estimates in homogeneous media (bias less than 0.2% and standard deviation less than 0.52%); however, in a two-layer phantom composed of water and agar-graphite, measured biases in the bottom layer exceeded 30 m/s while the standard deviation was approximately 10 m/s.…”
Section: Introductionmentioning
confidence: 99%
“…In the latter report, the mathematical deconvolution operator was used to retrieve a restored image produced by considering an ultrasound system PSF having different mean SoS values. A focusing approach based on the estimation of SoS along the wave propagation path was specifically introduced for the purpose of providing a tissue characterization signature in [ 35 ]. Conceptually, since a mean estimate along the ultrasound beam is obtained with these abovementioned methods [ 34 , 35 ], no local measure within a given ROI of an organ having inhomogeneous SoS can be produced.…”
Section: Speed Of Sound Imagingmentioning
confidence: 99%
“…A focusing approach based on the estimation of SoS along the wave propagation path was specifically introduced for the purpose of providing a tissue characterization signature in [ 35 ]. Conceptually, since a mean estimate along the ultrasound beam is obtained with these abovementioned methods [ 34 , 35 ], no local measure within a given ROI of an organ having inhomogeneous SoS can be produced. Current methods allowing local assessments or images within an ROI are based on spatial coherence [ 36 ] and image compounding [ 37 ] approaches .…”
Section: Speed Of Sound Imagingmentioning
confidence: 99%
“…In conventional ultrasound diagnostic equipment, an assumed average speed of sound is used for delay and sum beamforming to create a B-mode image that is generated by the RF signal of each received echo line. Conversely, as proposed by Ogawa and Umemura [ 20 ] and Hayashi et al [ 21 ], it is also possible to evaluate the average speed of sound from image quality. In the focusing method, beam focusing is repeated to optimize the local image quality and evaluate the speed of sound at that time.…”
Section: Speed Of Sound Evaluationmentioning
confidence: 99%