KR101117838B1 - Method for decreasing of spectral broadening and ultrasound system for the same - Google Patents

Abstract

The present invention relates to a method capable of reducing spectral broadening that may occur in Doppler spectral image formation and an ultrasonic system therefor. The ultrasound system of the present invention includes a Doppler signal acquisition unit for forming a Doppler signal according to a broadening reduction condition change and an optimum condition, forming a plurality of Doppler spectral images according to a change in the broadcasting reduction condition, and a plurality of Doppler spectra. A spectral broadcasting of an image calculates an optimal condition having a minimum value, and includes a processor configured to form an optimal Doppler spectrum image according to the optimal condition and a display unit configured to display an optimal spectrum Doppler image.

Description

Spectral Broadcasting Reduction Method and Ultrasonic System for the Field {METHOD FOR DECREASING OF SPECTRAL BROADENING AND ULTRASOUND SYSTEM FOR THE SAME}

TECHNICAL FIELD The present invention relates to the field of ultrasonic systems, and more particularly, to a method and an ultrasonic system for reducing the spectral broadening effect that may occur in the formation of Doppler spectral images.

Ultrasound systems have non-invasive and non-destructive properties and are widely used in the medical field for obtaining information inside an object. The ultrasound system is very important in the medical field because it can provide a doctor with a high resolution image of the internal tissue of the human body in real time without the need of a surgical operation to directly cut the body.

In general, an ultrasound system uses a B-mode in which a reflection coefficient of an ultrasound signal reflected from an object is a two-dimensional image, and a Doppler mode in which an image of a moving object (especially blood flow) is displayed using a Doppler effect. In addition, the present invention provides an elastic mode in which an image of the response difference between the compression and the compression is applied to the object. In particular, the Doppler mode is a frequency of an ultrasonic signal (hereinafter referred to as a transmission frequency) transmitted from an ultrasonic probe at a pulse repetition frequency (PRF) and a frequency of a Doppler signal received through a probe reflected from a moving object (hereinafter, received). Frequency (hereinafter referred to as Doppler frequency). That is, the reception frequency from the object approaching the ultrasound probe is higher than the transmission frequency, and the reception frequency from the object away from the ultrasound probe is lower than the transmission frequency to form a Doppler spectrum image.

The Doppler spectrum image may measure motion information of the object, and for example, may indicate a change in blood flow rate over time. Blood flow has a predetermined width because it is the fastest at the center of the blood vessel and slows toward the wall. Therefore, Doppler spectrum images are not thin lines but have a certain thickness. The height of the Doppler spectral image represents velocity or frequency, and the brightness represents the amount of blood flow with that velocity or frequency component. The space between the Doppler spectral curve and the horizontal baseline is called the spectral window. In the Doppler spectral image, various factors may cause a spectral broadening effect in which the spectral window is partially or wholly wider than the normal value.

The present invention relates to a method capable of reducing the spectral broadening effect that may occur in Doppler spectral image formation and an ultrasonic system therefor.

The ultrasonic system of the present invention includes a Doppler signal acquisition unit for forming a Doppler signal according to a broadening condition and a reduction condition of a broadening; Forming a plurality of Doppler spectral images according to the change in the broadcasting reduction condition, calculating the optimal condition having the minimum spectral broadcasting of the plurality of Doppler spectral images, and forming an optimal Doppler spectral image according to the optimal condition A processor; And a display unit configured to display the optimal spectrum Doppler image.

In addition, the spectral broadcasting effect reduction method of the present invention comprises the steps of: a) changing the broadening (broadening) reducing conditions at predetermined intervals; b) acquiring a Doppler signal according to the change in the broadcasting reduction condition; c) forming a plurality of Doppler spectral images based on the Doppler signal according to the change in the broadcasting reduction condition; d) extracting spectral broadcasting of the plurality of Doppler spectral images; e) calculating an optimal condition in which the spectral broadcasting of the plurality of Doppler spectral images has a minimum value; f) obtaining a Doppler signal according to the optimum condition; g) forming an optimal Doppler spectral image based on the Doppler signal according to the optimal condition; And h) displaying the optimal spectral Doppler image.

According to the present invention, it is possible to accurately measure information such as peak velocity, mean velocity, blood pressure, blood folw volume, etc. by reducing the spectral broadcasting effect in the Doppler spectrum image. have.

1 is a block diagram showing the configuration of an ultrasonic system according to an embodiment of the present invention.
Figure 2 is a block diagram showing the configuration of a Doppler signal acquisition unit according to an embodiment of the present invention.
3 is a block diagram showing a configuration of a processor according to an embodiment of the present invention.
4 is an exemplary view showing a Doppler spectral image for extraction of spectral broadcasting according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention. The term "Doppler mode" as used in this embodiment includes color doppler mode, spectral doppler mode and the like.

1 is a block diagram showing the configuration of an ultrasound system 100 according to an embodiment of the present invention. The ultrasound system 100 includes a Doppler signal acquirer 110, a processor 120, and a display 130.

The Doppler signal acquisition unit 110 transmits an ultrasound signal to an object according to a broadening condition and an optimum condition and receives an ultrasound signal (ie, an ultrasound echo signal) reflected from the object to obtain a Doppler signal. The broadcast reduction condition and the optimum condition will be described later. In this case, the Doppler signal includes a Doppler signal due to blood flow and a clutter siganl due to movement of the heart wall and the heart plate.

2 is a block diagram showing the configuration of a Doppler signal acquisition unit 110 according to an embodiment of the present invention. The Doppler signal acquisition unit 110 includes a transmission signal forming unit 112, an ultrasonic probe 114, a beamformer 116, and a Doppler signal forming unit 118.

The transmission signal forming unit 112 operates to form a transmission signal for obtaining a Doppler spectrum image. The transmission signal forming unit 112 forms a transmission signal so that the ultrasonic probe 114 may form ultrasonic waves in a plane wave form instead of a focused wave. In addition, the transmission signal forming unit 112 changes the ultrasound transmission / reception period of the ultrasound probe 114 in consideration of a target velocity representing an average of the moving speeds of the object during the broadcasting reduction condition. For example, when the representative speed of the object increases, the transmission signal forming unit 112 forms the transmission signal so that the ultrasound probe 114 may reduce the ultrasound transmission / reception period in proportion thereto.

The ultrasonic probe 114 operates to convert the transmission signal from the transmission signal forming unit 112 into an ultrasonic signal, transmit the ultrasonic signal to the observation area, and receive the ultrasonic echo signal reflected from the observation area to form a reception signal. The ultrasound signal transmitted by the ultrasound probe 114 to the observation area may be in the form of a plane wave rather than a focused wave according to the transmission signal, and a transmission / reception period may be changed according to the speed of the object.

The beamformer 116 operates to analog-to-digital convert the received signal from the ultrasonic probe 114 and to focus the received digitally converted received signal.

The Doppler signal forming unit 118 operates to form the Doppler signal by using the received focused signal.

The processor 120 performs various signal processing based on the Doppler signal provided from the Doppler signal acquisition unit 110, and according to an optimal condition in which a change in a broadcast reduction condition of a Doppler spectrum image and a spectral broadcasting effect are minimized. Form Doppler spectral images. The Doppler spectrum image may be used to measure the motion information of the object. For example, it may represent a change in blood flow rate over time. Blood flow has a predetermined width because it is the fastest at the center of the blood vessel and slows toward the wall. Therefore, Doppler spectrum images are not thin lines but have a certain thickness. The height of the Doppler spectral image represents velocity or frequency, and the brightness represents the amount of blood flow with that velocity or frequency component. The space between the Doppler spectral curve and the horizontal baseline is called the spectral window. In the Doppler spectral image, various factors may cause a spectral broadening effect in which the spectral window is partially or wholly wider than the normal value.

3 is a block diagram showing the configuration of a processor 120 according to an embodiment of the present invention. The processor 120 includes a signal processor 121, an image forming unit 122, a spectral broadcasting extractor 123, a storage unit 124, an optimal condition calculating unit 125, and a signal adjusting unit 126. .

The signal processor 121 analyzes the Doppler signal provided from the Doppler signal acquisition unit 110 and modulates the Doppler signal and changes the cutoff frequency of the clutter filter according to the analysis result. Signal processing is performed to remove the clutter signal from the Doppler signal and output only the Doppler signal. In addition, the signal processor 120 may further perform auto correlation, arc tangent, and the like on the Doppler signal.

The image forming unit 122 forms a Doppler spectral image according to a change in a broadcasting reduction condition and an optimal condition based on the Doppler signal from which the clutter signal provided from the signal processor 121 is removed. The broadcast reduction condition includes a sample volume size indicating the size of an area to detect a Doppler signal, a transmit beam indicating the shape of an ultrasound beam transmitted from an ultrasound probe, and transmission of an ultrasound signal. And an ultrasound aperture indicating the number of conversion elements used for reception, a target velocity indicating an average of the moving speeds of the object, and the like. The image forming unit 122 may form each Doppler spectrum image according to a broadcasting reduction condition changed at predetermined intervals. As a method of changing the broadcast reduction condition, a method of changing only one reduction condition of a plurality of broadcasting reduction conditions and keeping the remaining reduction conditions the same may be used. In addition, the image forming unit 122 forms an optimal Doppler spectrum image in which spectral broadcasting is minimized based on the Doppler signal formed according to the optimum condition formed by the optimum condition calculating unit 125.

The spectral broadcasting extractor 123 extracts spectral broadcasting of each Doppler spectrum image based on the Doppler spectrum image according to the change of the broadcasting reduction condition provided from the image forming unit 122. 4 is an exemplary view showing a Doppler spectrum image for extraction of spectral broadcasting according to an embodiment of the present invention. The degree of spectral broadcasting in the Doppler spectrum image may be represented by the size of the portion indicated by the arrow in FIG. 4. The spectral broadcasting extractor 123 may form spectral broadcasting by averaging the spectral broadcasting degree of a predetermined section (eg, within 2 seconds) on the time axis of the Doppler spectrum image.

The storage unit 124 stores the spectral broadcasting formed by the spectral broadcasting extraction unit 123. The storage unit 124 may store spectral broadcasting for each broadcast reduction condition.

The optimum condition calculating unit 125 calculates an optimum condition in which spectral broadcasting stored in the storage unit 124 has a minimum value.

The signal adjusting unit 126 changes the transmit / receive aperture, the ultrasonic beam focusing degree, the sample volume size, and the transmission period according to the optimum condition calculated by the optimum condition calculating unit 125 to form a Doppler signal. The control unit 110 controls.

Referring back to FIG. 1, the display 130 displays an optimal Doppler spectrum image according to an optimal condition formed by the processor 120. The display unit 130 may include a cathode ray tube (CRT) display, a liquid crystal display (LCD), an organic light emit diode (OLED) display, or the like.

 While the invention has been described and illustrated by way of preferred embodiments, those skilled in the art will recognize that various modifications and changes can be made without departing from the spirit and scope of the appended claims.

110: Doppler signal acquisition unit 120: processor
130: display unit 112: transmission signal forming unit
114: ultrasonic probe 116: beamformer
118: Doppler signal forming unit 121: signal processing unit
122: image forming unit 123: spectral broadcasting extraction unit
124: storage unit 125: optimum condition calculation unit
126: signal adjustment unit

Claims (12)

As an ultrasound system,
A Doppler signal acquisition unit configured to change a broadcasting reduction condition for reducing the spectral broadcasting effect and to form a Doppler signal according to an optimal condition;
Forming a plurality of Doppler spectral images according to the change in the broadcasting reduction condition, calculating the optimal condition having the minimum spectral broadcasting of the plurality of Doppler spectral images, and forming an optimal Doppler spectral image according to the optimal condition A processor; And
A display unit for displaying the optimal spectrum Doppler image
. The method of claim 1,
The Doppler signal acquisition unit
A transmission signal forming unit operable to form a transmission signal for forming the plurality of Doppler spectral images and the optimal Doppler spectral image;
An ultrasonic probe which converts the transmission signal from the transmission signal forming unit into an ultrasonic signal, transmits the ultrasonic signal to an observation region, and receives an ultrasonic echo signal reflected from the observation region to form a reception signal;
A beam former for analog-to-digital conversion of the received signal from the ultrasonic probe and for focusing the digitally converted received signal; And
A Doppler signal forming unit operable to form the Doppler signal using the received focused focus signal
. The method of claim 2,
The processor comprising:
A signal processor configured to analyze the Doppler signal provided from the Doppler signal acquirer and output various Doppler signals from which the clutter signal is removed from the Doppler signal by performing various signal processing of the Doppler signal according to an analysis result;
An image forming unit configured to form the plurality of Doppler spectral images and the optimal Doppler spectral image according to the change in the broadcasting reduction condition based on the Doppler signal from which the clutter signal is provided from the signal processor;
A spectral broadcasting extraction unit configured to extract spectral broadcasting of the plurality of Doppler spectrum images according to a change in the broadcasting reduction condition provided from the image forming unit;
A storage unit to store the spectral broadcasting;
An optimum condition calculating unit calculating the optimum condition corresponding to the minimum value of the spectral broadcasting; And
And a signal adjusting unit for controlling the Doppler signal obtaining unit to form a Doppler signal according to the calculated optimal condition. The method of claim 3,
The broadcast reduction condition is,
A sample volume size indicating a size of an area to detect the Doppler signal, a transmit beam indicating a shape of an ultrasound beam transmitted from the ultrasound probe, and transmitting and receiving the ultrasound signal An ultrasound system comprising an ultrasound aperture indicating the number of change elements to be used and a target velocity indicating an average of a moving speed of the object. The method of claim 4, wherein
The image forming unit, the ultrasound system to form the plurality of Doppler spectrum images by varying the broadcast reduction condition by a predetermined interval. The method of claim 5,
The spectrum broadcasting extraction unit,
And extracting the spectral broadcasting by averaging spectral broadcasting degrees of a predetermined section on the time axis of the plurality of Doppler spectrum images. As a method for reducing the spectral broadening effect,
a) changing a broadcasting reduction condition to reduce the spectral broadcasting effect at predetermined intervals;
b) acquiring a Doppler signal according to the change in the broadcasting reduction condition;
c) forming a plurality of Doppler spectral images based on the Doppler signal according to the change in the broadcasting reduction condition;
d) extracting spectral broadcasting of the plurality of Doppler spectral images;
e) calculating an optimal condition in which the spectral broadcasting of the plurality of Doppler spectral images has a minimum value;
f) obtaining a Doppler signal according to the optimum condition;
g) forming an optimal Doppler spectral image based on the Doppler signal according to the optimal condition; And
h) displaying the optimal spectral Doppler image.
Spectral broadcasting effect reduction method comprising a. The method of claim 7, wherein
Step c) is
c1) analyzing the Doppler signal according to the change of the broadcasting reduction condition and performing various signal processing of the Doppler signal according to the change of the broadcasting reduction condition according to the analysis result to output the Doppler signal from which the clutter signal is removed from the Doppler signal Making; And
c2) forming the plurality of Doppler spectrum images according to the change of the broadcasting reduction condition based on the Doppler signal from which the clutter signal is removed.
Spectral broadcasting effect reduction method comprising a. The method of claim 8,
Step c2),
Changing the broadcasting reduction condition by a predetermined interval to form the plurality of Doppler spectrum images.
Spectral broadcasting effect reduction method comprising a. The method of claim 7, wherein
Step d),
And extracting the spectral broadcasting by averaging the spectral broadcasting degree of a predetermined section on the time axis of the plurality of Doppler spectrum images. The method of claim 7, wherein
Step g),
g1) analyzing a Doppler signal according to the optimum condition and performing various signal processing of the Doppler signal according to the optimum condition according to the analysis result to output a Doppler signal from which the clutter signal is removed from the Doppler signal; And
g2) forming the optimal Doppler spectrum image according to the optimal condition based on the Doppler signal from which the clutter signal is removed
Spectral broadcasting effect reduction method comprising a. The method according to any one of claims 7 to 11,
The broadcast reduction condition is,
A sample volume size indicating the size of an area to detect a Doppler signal, a transmit beam indicating the shape of an ultrasound beam transmitted from an ultrasonic probe, and used for transmitting and receiving the ultrasonic signal A method of reducing spectral broadcasting effect including an ultrasonic aperture indicating the number of change elements to be converted and a target velocity indicating an average of a moving speed of an object.

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