Abstract:Though myocardial viscoelasticity is essential in the evaluation of heart diastolic properties, it has never been noninvasively measured in vivo. By the ultrasonic measurement of the myocardial motion, we have already found that some pulsive waves are spontaneously excited by aortic-valve closure (AVC) at end-systole (T0). In this study, a sparse sector scan at a sufficiently high frame rate clearly reveals wave propagation along the heart wall. The propagation time of the wave along the heart wall is very sma… Show more
“…Dynamic elastography is certain to be a promising tool of diagnostic imaging for clinical tissue characterization, because the dynamic images of tissue-oriented physical parameter, physical structure, and their dynamical behavior can be revealed by an advanced modification of the conventional ultrasonic beam-scattering system 1,2) surpassing the conventional static elastography. Meanwhile by introducing synthetic aperture (SA) array signal processing of a two-dimensional (2D) echo acquired in real-time from arrayed transducer elements that were triggered by a pulsed wide irradiation, ultrahigh speed ultrasonic imaging can maximally be brought to reality.…”
order to do the parametrization independent analysis, additionally we adopt the so called principal component analysis (PCA) method, in which we divide redshift range into several bins and assume w as a constant in each redshift bin (bin-w). In such bin-w scenario, we find that for most of the bins cosmological constant can be comparable with the data, however, there exists few bins which give w deviating from ΛCDM at more than 2σ confidence level, which shows a weak hint for the time evolving behavior of dark energy. To further confirm this hint, we need more data with higher precision.
“…Dynamic elastography is certain to be a promising tool of diagnostic imaging for clinical tissue characterization, because the dynamic images of tissue-oriented physical parameter, physical structure, and their dynamical behavior can be revealed by an advanced modification of the conventional ultrasonic beam-scattering system 1,2) surpassing the conventional static elastography. Meanwhile by introducing synthetic aperture (SA) array signal processing of a two-dimensional (2D) echo acquired in real-time from arrayed transducer elements that were triggered by a pulsed wide irradiation, ultrahigh speed ultrasonic imaging can maximally be brought to reality.…”
order to do the parametrization independent analysis, additionally we adopt the so called principal component analysis (PCA) method, in which we divide redshift range into several bins and assume w as a constant in each redshift bin (bin-w). In such bin-w scenario, we find that for most of the bins cosmological constant can be comparable with the data, however, there exists few bins which give w deviating from ΛCDM at more than 2σ confidence level, which shows a weak hint for the time evolving behavior of dark energy. To further confirm this hint, we need more data with higher precision.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.