Ultrasound Database • ![]() 'Fully software controlled Image Processing (F-XT technology) Color Doppler & Power Doppler display available Autofocus function for transmission High-resolution SVGA display Cine memory with 128 frames Wide band Probe for multi frequency function 6-step STC adjustment DICOM-compatible Ethernet port 3.5-inch 640MB drive for image filing' •
(FOV) The field of view is the plane or area depicted by the ultrasound transducer.
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The gas in microbubbles is highly compressible and, when subjected to the alternating compression and refraction pressures that constitute an ultrasound pulse, microbubbles oscillate at their natural frequency at which they resonate most strongly. This is determined by their size but is also influenced by the composition of the filling gas. Air, sulfur hexafluoride, nitrogen, and perfluorochemicals are used as filling gases. Most newer ultrasound contrast agents use perfluorochemicals because of their low solubility in blood and high vapor pressure. By substituting different types of perfluorocarbon gases for air, the stability and plasma longevity of the agents have been markedly improved, usually lasting more than five minutes. •
A filter in electronics is a circuit that only passes certain signals. In ultrasound is a filter a device to suppress acoustic or electromagnetic waves of certain frequencies, letting other frequencies pass, e.g. high pass filter, low pass filter. The high pass filter is the wall filter (also called thump filter) used in Doppler devices to eliminate low frequency Doppler shifts caused by clutter. For blood flow measurement, a low pass filter is often used to strip out high frequency noise, leaving only the biological components of interest. Frame averaging is a form of a low pass filter.
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The first generation ultrasound contrast agents (UCA/USCA) do not pass the pulmonary vascular bed, and are therefore limited to the venous system and the right heart cavities after intravenous injection.
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