نتایج جستجو برای: transcranial doppler ultrasonography
تعداد نتایج: 92398 فیلتر نتایج به سال:
Although Doppler colour flow mapping may considerably reduce the need for conventional pulsed Doppler examination, quantitative flow measurements (particularly by continuous wave Doppler) are still essential in the evaluation of many conditions such as aortic stenosis. Doppler colour flow mapping is an important addition to the accurate non-invasive evaluation of several haemodynamic disorders ...
From the flow of a suspension of micrometer-scale carbon particles, the photoacoustic Doppler shift is observed. As predicted theoretically, the observed Doppler shift equals half of that in Doppler ultrasound and does not depend on the direction of laser illumination. This new physical phenomenon provides a basis for developing photoacoustic Doppler flowmetry, which can potentially be used for...
Owing to its versatile, non-invasive, radiation-free, and low cost nature, Doppler echocardiography is undoubtedly the method of choice to evaluate prosthetic valve function. This evaluation follows the same principles used for the evaluation of native valves, with some important specifics and caveats described in this article. A complete echocardiography includes two dimensional imaging of the...
While photonic Doppler velocimetry (PDV) is becoming a common diagnostic in dynamic compression research, its limiting accuracy and precision are not well understood. Velocity resolution is known to be inversely proportional to the time resolution, but resolution estimates differ by one to two orders of magnitude. Furthermore, resolution varies with the number of recorded signals and how these ...
Atmospheric depolarization ratio and wind velocity are measured simultaneously by a single versatile coherent Doppler lidar (CDL). Backscattering components at parallel and perpendicular polarization states are obtained by using a single balanced detector, adopting time-division multiplexing technique. Thus systematic error induced by the non-uniform response of different detectors in tradition...
During open brain surgery we acquire perfusion images non-invasively using laser Doppler imaging. The regions of brain activity show a distinct signal in response to stimulation providing intraoperative functional brain maps of remarkably strong contrast.
BACKGROUND Ultrasonography (US) studies carried out on joints of juvenile idiopathic arthritis (JIA) patients in clinical remission demonstrate the presence of subclinical synovitis. The significance of subclinical synovitis and the positive power Doppler (PD) signal on US in JIA in clinical remission is not well understood. The objectives of this study were to assess whether the changes detect...
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