نتایج جستجو برای: spectral doppler indices
تعداد نتایج: 286104 فیلتر نتایج به سال:
Background and purpose: Doppler sonography is a noninvasive diagnostic procedure with no side effect witch is cost effective and the results are rapidly available. Two indices are explained in the field of Doppler sonographic hemodynamic evaluation, PÏ* and RÏ**, Âbnormal ranges are PÏ ≥ 1.8 and RÏ ≥ 0.7 . Ïn previous studies average PÏ in normal conditions was 1.5 and in rejected trans...
In previous publications, a new echo-ranging Doppler system based on transmission of repetitive coherent frequency-modulated ͑FM͒ sinusoids in two different implementations was presented. One of these implementations, the frequency-modulated–frequency-shift measurement ͑FM–fsm͒ Doppler system is, in this paper, compared with its pulsed-wave counterpart, the pulsed-wave– time-shift measurement ͑PW–ts...
Stars within the innermost part of nuclear star cluster can reach orbital velocities up to a few percent light speed. As analyzed by Rafikov, Doppler boosting stellar may be relevance at pericenter orbits, especially with upcoming high-precision photometry in near- and mid-infrared bands. Here we analyze previously neglected effect infrared spectral index monitored objects on Doppler-boosted co...
Spectral waveform analysis of blood flow velocity in the major arteries of six healthy, conscious immature micropigs was determined using Doppler ultrasonography. Doppler spectral tracings were recorded from the external iliac artery, femoral artery, and renal arcuate artery. Tracings were also taken from three parts of the common carotid artery and two parts of the abdominal aorta. Spectral Do...
BACKGROUND The origin, control mechanisms, and functional significance of oscillations in microvascular flow are incompletely understood. Although the traditional belief has been that only low-frequency oscillations (0.04-0.10 Hz) can originate at the microvascular level, recent evidence in healthy volunteers has suggested that high-frequency oscillations (> 0.10 Hz) also may have a microvascul...
In this study, Doppler signals recorded from internal carotid artery of 45 subjects were processed by PC-computer using classical (fast Fourier transform) and model-based (autoregressive, moving average, autoregressive moving average (ARMA) methods) methods. Power spectral density estimates of internal carotid arterial Doppler signals were obtained using these spectral analysis methods. The var...
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