Method and device for elasticity detection

1. A method for elasticity detection, comprising:

step 1: maintaining an excitation device and an ultrasonic transducer in contact with a surface of a tissue during N elasticity detections; controlling the excitation device to periodically excite N shear waves in the tissue at a preset time interval, wherein the N shear waves are continuously excited within the preset time interval without manually locating the excitation device several times on the surface of the tissue so as to ensure that the N shear waves are excited in respect to a same position, and controlling the ultrasonic transducer to transmit an ultrasonic wave to the tissue, wherein N is an integer greater than 1, and wherein the excitation device is the same as the ultrasonic transducer for transmitting the ultrasonic wave;

step 2: receiving, by the ultrasonic transducer, an ultrasonic echo signal corresponding to each of the shear waves;

step 3: obtaining a propagation characteristic parameter of each of the shear waves according to the ultrasonic echo signal corresponding to each of the shear waves;

step 4: calculating elasticity parameters of the tissue according to propagation characteristic parameters of the N shear waves and according to a known tissue density of the tissue, wherein the elasticity parameters comprise mechanical impedance, mechanical relaxation time and anisotropy, and wherein the propagation characteristic parameters comprise a propagation attenuation coefficient;

wherein the step 1 comprises:

controlling the ultrasonic transducer to transmit ultrasonic waves to the tissue at different angles or different frequencies, wherein the N shear waves have different frequencies;

wherein the step 4 comprises:

calculating the elasticity parameters of the tissue corresponding to each of the shear waves according to the propagation characteristic parameter of each of the shear waves and according to the known tissue density; and

calculating an average value of elasticity parameters of the tissue corresponding to the N shear waves as the elasticity parameters of the tissue;

wherein the step 3 comprises:

acquiring a tissue motion parameter corresponding to each of the shear waves by performing signal processing on the ultrasonic echo signal corresponding to each of the shear waves, wherein the signal processing comprises at least one of the following: spot tracking and zero cross-tracking; and

acquiring a propagation characteristic parameter of each of the shear waves according to the tissue motion parameter corresponding to each of the shear waves;

wherein after the step 4, the method further comprises:

mapping the elasticity parameters of the tissue into a corresponding grayscale or color image by using a grayscale or color mapping to obtain an elasticity image.

2. The method according to claim 1 , wherein the tissue motion parameter comprises a displacement or a strain.

3. The method according to claim 1 , wherein the elasticity parameters further comprise at least one of following parameters: shear modulus, Young's modulus and shear elasticity, shear viscosity.

4. The method according to claim 1 , wherein an excitation mode of the shear waves are that an ultrasonic wave transmitted by the ultrasonic transducer focuses inside the tissue to generate an acoustic radiation force so as to produce shear waves in the tissue.

5. A device for elasticity detection, comprising:

a control host, an excitation device and an ultrasonic transducer; where the excitation device and the ultrasound transducer are maintained in contact with a surface of a tissue during N elasticity detections, wherein the excitation device is the same as the ultrasonic transducer for transmitting the ultrasonic wave; and

the control host comprises a processor and a memory storing instructions thereon, the processor when executing the instructions, being configured to:

control the excitation device to periodically excite N shear waves in the tissue at a preset time interval, wherein the N shear waves are continuously excited within the preset time interval without manually locating the excitation device several times on the surface of the tissue so as to ensure that the N shear waves are excited in respect to a same position and control the ultrasonic transducer to transmit ultrasonic waves to the tissue, N being an integer greater than 1;

receive by the ultrasonic transducer an ultrasonic echo signal corresponding to each of the shear waves;

acquire a propagation characteristic parameter of each of the shear waves according to the ultrasonic echo signal corresponding to each of the shear waves; and

calculate elasticity parameters of the tissue according to propagation characteristic parameters of the N shear waves and according to a known tissue density of the tissue, wherein the elasticity parameters comprise mechanical impedance, mechanical relaxation time and anisotropy, and wherein the propagation characteristic parameters comprise a propagation attenuation coefficient;

wherein the processor is specifically configured to control the ultrasonic transducer to transmit ultrasonic waves to the tissue at different angles or different frequencies, wherein the N shear waves have different frequencies;

wherein the processor is specifically configured to

calculate the elasticity parameters of the tissue corresponding to each of the shear waves according to the propagation characteristic parameter of each of the shear waves and according to the known tissue density; and calculate an average value of elasticity parameters of the tissue corresponding to the N shear waves as the elasticity parameter of the tissue;

wherein the processor is specifically configured to acquire a tissue motion parameter corresponding to each of the shear waves by performing signal processing on the ultrasonic echo signal corresponding to each of the shear waves, wherein the signal processing comprises at least one of the following: spot tracking and zero cross-tracking; and acquire a propagation characteristic parameter of each of the shear waves according to the tissue motion parameter corresponding to each of the shear waves;

wherein the processor is specifically configured to map the elasticity parameters of the tissue into a corresponding grayscale or color image by using a grayscale or color mapping to obtain an elasticity image.