A technique known as Time Delay Spectrometry (TDS), which has been used at JPL for ultrasonic tissue characterization, has promise for similar application in materials characterization as well. This technique differs from the approaches based on pulse-echo techniques which are used by other workers. Time Delay Spectrometry operates in the frequency domain directly. The transducer is excited by ...

Ultrasonic tissue characterization is a new area of investigation in the field of cardiac ultrasound. The amplitude and frequency of the ultrasound signal are normally altered as the signal penetrates through tissue. It is assumed that the amplitude distribution and frequency shift of diseased or edematous tissue are different than those of normal tissue. A statistical approach to the analysis ...

Intensity variations in image texture can provide powerful quantitative information about physical properties of biological tissue. However, tissue patterns can vary according to the utilized imaging system and are intrinsically correlated to the scale of analysis. In the case of ultrasound, the Nakagami distribution is a general model of the ultrasonic backscattering envelope under various sca...

To determine whether collagen content may be a determinant of the ultrasonic attenuation and backscatter in myocardium and to identify factors in the measurement of the backscatter coefficient needed for ultrasonic characterization of myocardium in vivo, two series of experiments were conducted. In the first series, the ultrasonic attenuation was measured from 110 regions in 18 dogs studied 2, ...

A sensor for in vivo biomechanical characterization of buttock soft tissue has been developed and evaluated. The sensor measures interface pressure, applied force, tilt, and rotation angle of the sensor head, and the thicknesses of multiple soft tissue layers. A composite ultrasonic transducer using a 1-3 ceramic-polymer structure was developed for the sensor. The sensor can identify subcutaneo...

The excess ultrasonic attenuation caused by adding glycogen and inorganic phosphate to liver homogenates has been studied to determine the underlying differences between attenuation coefficients of normal and diffusely diseased livers. Results show that glycogen has a higher than average specific absorption coefficient compared to other large molecular weight biomolecules. Since the glycogen co...

Actocardiogram: Ultrasonic Doppler actocardiogram was simultaneous tracing of FHR and fetal movement signals on the monitoring chart, created in 1984 by Maeda. Fetal behavior was easily studied, false-positive nonreactive FHR and physiological sinusoidal FHR were differentiated, the severity of fetal CNS lesion and common fetal disorders were determined, short and long-term outcomes were diagno...

Speckle is an inherent characteristic of tissues when assessed by ultrasound. De-speckling is performed to improve the visualization of anatomical details but the information encoded in speckle is often discarded. In this paper we propose an ultrasonic decomposition procedure which estimates despeckled and speckle images starting with images created from Radio Frequency (RF) data. These images ...

Broadband ultrasonic pulses and monochromatic ultrasonic waves are visualized in various transparent solids using a photoelastic visualization technique. Application is made to the characterization of the sound field radiated by various ultrasonic transducers operating under various excitation and coupling