Juvenal Ormachea

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Sonoelastography is an ultrasonic technique that provides qualitative and quantitative images of tissue elasticity. Even though the Kasai variance estimator is a key part of the sonoelastographic image formation, there are no studies that demonstrate that its performance using discrete time signals and finite sized ensemble lengths is optimal. In this work,(More)
The placenta is the critical interface between the mother and the developing fetus and is essential for survival and growth. Despite the widespread use of ultrasound imaging and Doppler in obstetrics and gynecology and the recent growth of elastographic technologies, little is known about the biomechanical (elastic shear wave) properties of the placenta and(More)
Elasticity imaging can be understood as the intersection of the study of biomechanical properties, imaging sciences, and physics. It was mainly motivated by the fact that pathological tissue presents an increased stiffness when compared to surrounding normal tissue. In the last two decades, research on elasticity imaging has been an international and(More)
The frequency dependent behavior of tissue stiffness and the dispersion of shear waves in tissue can be measured in a number of ways, using integrated imaging systems. The microchannel flow model, which considers the effects of fluid flow in the branching vasculature and microchannels of soft tissues, makes specific predictions about the nature of(More)
A novel method for estimating the shear wave speed from crawling waves based on the amplitude modulation-frequency modulation model is proposed. Our method consists of a two-step approach for estimating the stiffness parameter at the central region of the material of interest. First, narrowband signals are isolated in the time dimension to recover the(More)
A number of shear wave speed estimators have been developed for crawling wave sonoelastography. In this study, a new low-cost estimator based on spatial wavelength averaging along the slow-time domain is presented while assessing its performance through gelatin-based inclusion and homogeneous phantoms. Results showed favorable estimation mean accuracy(More)
—Crawling wave sonoelastography enables the measurement of viscoelastic properties of soft tissue. Recently, the dominant component analysis AM-FM method was proposed for modeling non-stationary patterns in crawling wave sonoe-lastography to locally estimate their shear wave speed. Although evaluations show consistent results for homogeneous and(More)
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