Distributed processor for noninvasive blood flow analysis
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High-resolution ultrasound imaging of peripheral arteries offers a powerful technique for screening of potential stroke victims. However, the technique becomes inaccurate in cases of low-grade stenosis and the presence of noncalcified plaque. In these cases Doppler flow measurement can be used to augment the imaging system to arrive at a more accurate diagnosis. This paper describes a duplex system that combines high-resolution imaging with Doppler measurements. The various real-time processing and control tasks are implemented in a distributed processing system using three different processors. A high-speed digital signal processor (DSP) performs Fourier transforms on the Doppler-shifted signals and also performs some of the premultiplications required for Doppler parameter computations. A dedicated Doppler CPU receives the spectral coefficients from the DSP and computes several parameters such as gray-scale spectrogram coefficients, frequency centroids, spectral broadening coefficients, and velocity profiles. A third CPU is used to control the imaging system and to perform the housekeeping tasks such as control of the video display and the interface with the control panel.
KeywordsDigital Signal Processor Doppler Flow Doppler Measurement Video Display Doppler Parameter
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