نتایج جستجو برای: fractional flow
تعداد نتایج: 537166 فیلتر نتایج به سال:
Heyndrickx GR. Intracoronary and intravenous adenosine 50-triphosphate, adenosine, papaverine, and contrast medium to assess fractional flow reserve in humans. Circulation 2003;107:1877–1883. 21. Pijls N, van Son J, Kirkeeide R, De Bruyne B, Gould K. Experimental basis of determining maximum coronary, myocardial, and collateral blood flow by pressure measurements for assessing functional stenos...
This paper introduces a new fractional variational optical flow model, which combines the fractional derivative with the variational optical flow method, for motion estimation. In the model, the data term is a weighted least-squares fit of local brightness constraint function and the prior term is a fractional derivative penalty function. So the proposed model can be seen as generalizations of ...
INTRODUCTION AND OBJECTIVES Intracoronary ultrasound estimation of the functional significance of intermediate angiographic lesions has mainly been based on measuring the minimal lumen area. These estimates take no account of lesion length and pay insufficient attention to long coronary lesions. METHODS We included 61 lesions with visual angiographic stenosis of 40% to 70% that required treat...
BACKGROUND The aim of this study was to investigate the impact of varying hemodynamic conditions on fractional flow reserve (ratio of pressure distal [Pd] and proximal [Pa] to stenosis under hyperemia) in an in vitro setting. Failure to achieve maximal hyperemia and the choice of hyperemic agents may have differential effects on coronary hemodynamics and, consequently, on the determination of f...
There is an urgent need for stroke experts to advance the care of their patients, yet current approaches are outmoded and have not been successful. The traditional emphasis on anatomical identification of disease, using percent luminal stenosis, results in suboptimal identification of lesions likely to produce recurrent ischemia and, consequently, results in poor patient selection and hampers t...
A fractional step lattice Boltzmann scheme is presented to greatly improve the stability of the lattice Boltzmann method (LBM) in modelling incompressible flows at high Reynolds number. This method combines the good features of the conventional LBM and the fractional step technique. Through the fractional step, the flow at an extreme case of infinite Reynolds number (inviscid flow) can be effec...
Ma Fractional flow reserve (FFR) is the “gold standard” for assessing the physiological significance of coronary artery disease during invasive coronary angiography. FFR-guided percutaneous coronary intervention improves patient outcomes and reduces stent insertion and cost; yet, due to several practical and operator related factors, it is used in <10% of percutaneous coronary intervention proc...
Fractional flow reserve derived from coronary computed tomography angiography enables noninvasive assessment of the hemodynamic significance of coronary artery lesions and coupling of the anatomic severity of a coronary stenosis with its physiological effects. Since its initial demonstration of feasibility of use in humans in 2011, a significant body of clinical evidence has developed to evalua...
Fractional flow formulations of the multi-phase flow equations exhibit several attractive attributes for numerical simulations. The governing equations are a saturation equation having an advection diffusion form, for which characteristic methods are suited, and a global pressure equation whose form is elliptic. The fractional flow approach to the governing equations is compared with other appr...
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