Background Residual background phase in cardiac phase-contrast (PC) imaging introduces velocity errors that bias quantitative flow measurements [1]. While the bias can be offset using static phantoms [2], improved workflow is realized if self-calibrated correction is performed by fitting the phase of static tissue from the in vivo images. However, the residual phase can be nonlinear in space an...

This paper describes an indentometer device used to identify the linear dynamic and nonlinear properties of skin and underlying tissue using an in vivo test. The device uses a Lorentz force actuator to apply a dynamic force to the skin and measures the resulting displacement. It was found that the skin could be modeled as a Wiener system (i.e. a linear dynamic system followed by a static nonlin...

Non-invasively focusing light into strongly scattering media, such as biological tissue, is highly desirable but challenging. Recently, ultrasonically guided wavefront shaping technologies have been developed to address this limitation. So far, the focusing resolution of most implementations has been limited by acoustic diffraction. Here, we introduce nonlinear photoacoustically guided wavefron...

The nonlinear viscoelastic behavior of brain tissue that was observed in oscillatory shear tests was modeled with a quasilinear viscoelastic constitutive relation. The dynamic viscoelastic behavior of brain tissue has been previously modeled with only linear models. The reader is referred to Darvish (2000) for a review of the previous models. Studies on live neural tissue (Thibault et al., 1990...

A method is introduced for using measurements made in water of the nonlinear acoustic pressure field produced by a high-intensity focused ultrasound transducer to compute the acoustic pressure and temperature rise in a tissue medium. The acoustic pressure harmonics generated by nonlinear propagation are represented as a sum of modes having a Gaussian functional dependence in the radial directio...

Suki B, Bates JH. Lung tissue mechanics as an emergent phenomenon. J Appl Physiol 110: 1111–1118, 2011. First published January 6, 2011; doi:10.1152/japplphysiol.01244.2010.—The mechanical properties of lung parenchymal tissue are both elastic and dissipative, as well as being highly nonlinear. These properties cannot be fully understood, however, in terms of the individual constituents of the ...