نتایج جستجو برای: dimensional speckle
تعداد نتایج: 406318 فیلتر نتایج به سال:
objectives our aim was to study the relation between vac and the parameters of myocardial mechanics using three-dimensional speckle-tracking echocardiography (3dste). patients and methods we studied 68 normal participants (mean age, 35 ± 12.2 y; 36 [53%] males). vac was measured by the ratio of arterial elastance (ea) to ventricular elastance (ees). the peak systolic value of longitudinal strai...
left atrial (la) distension has been demonstrated to be linked with aortic stiffness in different patient populations. three-dimensional (3d) speckle-tracking echocardiography (ste) seems to be a promising tool for volumetric and functional evaluation of the la. the aim of the present study was to determine whether correlations exist between 3dste-derived la volume-based and strain parameter...
Speckle tracking methods overcome the major limitations of current Doppler methods for flow imaging and quantification: angle dependence and aliasing. In this paper, we review the development of speckle tracking, with particular attention to the advantages and limitations of two-dimensional algorithms that use a single transducer aperture. Ensemble tracking, a recent speckle tracking method bas...
A novel tomographic method based on the laser speckle contrast, speckle contrast optical tomography (SCOT) is introduced that allows us to reconstruct three dimensional distribution of blood flow in deep tissues. This method is analogous to the diffuse optical tomography (DOT) but for deep tissue blood flow. We develop a reconstruction algorithm based on first Born approximation to generate thr...
We calculate the statistical distribution P2(I2) of the speckle pattern produced by a photon pair current I2 transmitted through a random medium, and compare it with the single-photon speckle distribution P1(I1). We show that the purity of a two-photon density matrix can be directly extracted from the first two moments of P1 and P2. A one-to-one relationship is derived between P1 and P2 if the ...
BACKGROUND We have previously reported strain dyssynchrony index assessed by two-dimensional speckle tracking strain, and a marker of both dyssynchrony and residual myocardial contractility, can predict response to cardiac resynchronization therapy (CRT). A newly developed three-dimensional (3-D) speckle tracking system can quantify endocardial area change ratio (area strain), which coupled wit...
The purpose of the study is to show a proposal of an extension of a one-dimensional speckle correlation method, which is primarily intended for determination of one-dimensional object's translation, for detection of general in-plane object's translation. In that view, a numerical simulation of a displacement of the speckle field as a consequence of general in-plane object's translation is prese...
Case summary A 5-month-old intact female Scottish Fold cat was presented for cardiac evaluation. Careful auscultation detected a slight systolic murmur (Levine I/VI). The findings of electrocardiography, thoracic radiography, non-invasive blood pressure measurements and conventional echocardiographic studies were unremarkable. However, two-dimensional speckle tracking echocardiography revealed ...
An optical identification system of a three-dimensional (3D) random phase object by use of speckle patterns in different propagation distances is proposed and evaluated experimentally. The 3D random phase object is used as a 3D key. It can be secure when the scattering is strong enough because the interferometric measurement is not applied. The identification is implemented by evaluating crossc...
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