Automatic detection system and method of spectral Doppler blood flow velocity
First Claim
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1. A method for determining frequency shift parameters relating to blood flow characteristics, comprising:
- obtaining a plurality of Doppler signals from ultrasonic echoes acquired from a patient during a first basic time interval using an ultrasonic Doppler device;
determining a power spectral density of the Doppler signals acquired during the first basic time interval;
analyzing the power spectral density of the Doppler signals to obtain one or more power spectral lines;
calculating a noise threshold of the power spectral density of the Doppler signals acquired during the first basic time interval using a mean noise level of a previous basic time interval;
calculating a mean noise level of the power spectral density of the first basic time interval using the mean noise level of the previous basic time interval, the power spectral density of the Doppler signals acquired during the first basic time interval, and the noise threshold; and
determining frequency shift parameters relating to the blood flow characteristics corresponding to a selected one of the one or more power spectral lines using the mean noise level of the first basic time interval, the noise threshold, and the selected power spectral line, wherein the frequency shift parameters comprise a maximum frequency shift and a mean frequency shift, and wherein one or more of the frequency shift parameters determines a blood flow velocity.
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Abstract
A method and system for detecting spectral Doppler blood flow velocity are disclosed. The method comprises the steps of: obtaining Doppler signals of the flow by demodulating, filtering, and analog-to-digital converting RF ultrasonic echoes; analyzing the spectrum of the Doppler signals to obtain each of the power spectral lines of the Doppler signal varying with time; determining a threshold; and determining the frequency shift parameters or the blood flow velocity corresponding to the current power spectral line based on the threshold and the current power spectral line.
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Citations
20 Claims
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1. A method for determining frequency shift parameters relating to blood flow characteristics, comprising:
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obtaining a plurality of Doppler signals from ultrasonic echoes acquired from a patient during a first basic time interval using an ultrasonic Doppler device; determining a power spectral density of the Doppler signals acquired during the first basic time interval; analyzing the power spectral density of the Doppler signals to obtain one or more power spectral lines; calculating a noise threshold of the power spectral density of the Doppler signals acquired during the first basic time interval using a mean noise level of a previous basic time interval; calculating a mean noise level of the power spectral density of the first basic time interval using the mean noise level of the previous basic time interval, the power spectral density of the Doppler signals acquired during the first basic time interval, and the noise threshold; and determining frequency shift parameters relating to the blood flow characteristics corresponding to a selected one of the one or more power spectral lines using the mean noise level of the first basic time interval, the noise threshold, and the selected power spectral line, wherein the frequency shift parameters comprise a maximum frequency shift and a mean frequency shift, and wherein one or more of the frequency shift parameters determines a blood flow velocity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for determining frequency shift parameters relating to blood flow characteristics, comprising:
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means for obtaining a plurality of Doppler signals from ultrasonic echoes acquired from a patient during a first basic time interval using an ultrasonic Doppler device; means for determining a power spectral density of the Doppler signals acquired during the first basic time interval; means for analyzing the power spectral density of the Doppler signals to obtain one or more power spectral lines; means for calculating a noise threshold of the power spectral density of the Doppler signals acquired during the first basic time interval using a mean noise level of a previous basic time interval; means for calculating a mean noise level of the power spectral density of the first basic time interval using the mean noise level of the previous basic time interval, the power spectral density of the Doppler signals acquired during the first basic time interval, and the noise threshold; and means for determining frequency shift parameters relating to the blood flow characteristics corresponding to a selected one of the one or more power spectral lines using the mean noise level of the first basic time interval, the noise threshold, and the selected power spectral line, wherein the frequency shift parameters comprise a maximum frequency shift and a mean frequency shift, and wherein one or more of the frequency shift parameters determines a velocity of the blood flow. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification