Ultrasound system and method for generating elastic image

1. A method for generating an elastic image of a target object in an ultrasound system, comprising:

setting a Doppler gate at a predetermined location in an image of the target object;

acquiring a plurality of frames of B-mode ultrasound data from the target object while an ultrasound probe movement applies a variable compression force on the target object;

acquiring a plurality of frames of Doppler-mode ultrasound data from the target object based on the Doppler gate while the ultrasound probe movement applies the variable compression force on the target object;

determining a period for a cycle of the ultrasound probe movement based on the Doppler-mode ultrasound data, wherein determining the period comprises:

filtering the Doppler-mode ultrasound data;

calculating a center frequency of the filtered Doppler-mode ultrasound data; and

determining the period for the cycle of the ultrasound probe movement based on the center frequency;

selecting two frames of the B-mode ultrasound data based on the period for the cycle of the ultrasound probe movement; and

generating the elastic image of the target object based on the selected frames of the B-mode ultrasound data.

2. The method of claim 1 , wherein filtering the Doppler-mode ultrasound data comprises filtering the Doppler-mode ultrasound data by using a low pass filter.

3. The method of claim 1 , wherein the plurality of frames of B-mode ultrasound data are acquired sequentially, and

wherein selecting the two frames of the B-mode ultrasound data comprises:

selecting a first frame from the plurality of frames of B-mode ultrasound data; and

selecting a second frame from the frames of B-mode ultrasound data preceding the first frame based on the period.

4. The method of claim 3 , wherein the second frame precedes the first frame by a specified number of frames, and

wherein selecting the second frame from the frames of B-mode ultrasound data comprises calculating the specified number of frames according to the following equation:

F

=

T

×

F

r

2

wherein F represents the specified number of frames, T represents the period, and F r represents a frame rate for the frames of the B-mode ultrasound data.

5. The method of claim 1 , wherein the predetermined location of the Doppler gate is within 1 cm from a surface of the target object when the surface is in contact with the ultrasound probe.

6. The method of claim 1 , wherein a pulse repetition frequency for each of the plurality of the frames of the Doppler-mode ultrasound data is less than or equal to 100 Hz.

7. The method of claim 1 , further comprising:

generating a guideline configured to guide movement of the ultrasound probe based on the period; and

displaying the guideline as a graph.

8. The method of claim 1 , further comprising:

generating guide sound configured to guide the ultrasound probe movement based on the period; and

outputting the guide sound.

9. An ultrasound system, comprising:

an ultrasound probe configured to transmit ultrasound signals into a target object and receive ultrasound echo signals from the target object while applying a variable compression force on the target object;

a processor configured to set a Doppler gate at a predetermined location in an image of the target object, the predetermined location of the Doppler gate being within 1 cm from a surface of the target object when the surface is in contact with the ultrasound probe and while the variable compression force is applied on the target object, generate a plurality of frames of B-mode ultrasound data while the variable compression force is applied on the target object based on the ultrasound echo signals, generate a plurality of frames of Doppler-mode ultrasound data based on the Doppler gate while the variable compression force is applied on the target object based on the ultrasound echo signals, determine a period for a cycle of the variable compression force from the ultrasound probe based on the Doppler-mode ultrasound data, select two frames of the B-mode ultrasound data based on the period for the cycle of the variable compressive force, and generate an elastic image of the target object based on the selected frames of the B-mode ultrasound data, wherein the processor comprises:

a filtering section configured to filter the Doppler-mode ultrasound data;

a center frequency calculating section configured to calculate a center frequency of the filtered Doppler-mode ultrasound data; and

a period determining section configured to determine the period based on the center frequency; and

a display unit configured to display the elastic image.

10. The ultrasound system of claim 9 , wherein the filtering section comprises a low pass filter.

11. The ultrasound system of claim 9 , the plurality of frames of B-mode ultrasound data are generated sequentially, and

wherein the processor comprises a frame selecting section configured to select a first frame from the plurality of frames of B-mode ultrasound data, and select a second frame from the frames of B-mode ultrasound data preceding the first frame based on the period.

12. The method of claim 11 , wherein the second frame precedes the first frame by a specified number of frames, and

wherein the frame selecting section is configured to calculate the specified number of frames according to the following equation:

F

=

T

×

F

r

2

wherein F represents the specified number of frames, T represents the period, and F r represents a frame rate for the frames of the B-mode ultrasound data.

13. The ultrasound system of claim 9 , wherein a pulse repetition frequency for each of the plurality of the frames of the Doppler-mode ultrasound data is less than or equal to 100 Hz.

14. The ultrasound system of claim 9 , wherein the processor further comprises a guideline generating section configured to generate a guideline configured to guide movement of the ultrasound probe based on the period, and

wherein the display unit is further configured to display the guideline as a graph.

15. The ultrasound system of claim 9 , wherein the processor further comprises a guide sound generating section configured to generate guide sound configured to guide movement of the ultrasound probe based on the period.

16. The ultrasound system of claim 15 , further comprising:

a speaker configured to output the guide sound.