METHOD AND DEVICE FOR DETECTING ELASTICITY OF VISCOUS ELASTIC MEDIUM

• US 20120271166A1
• Filed: 10/14/2010
• Published: 10/25/2012
• Est. Priority Date: 10/15/2009
• Status: Active Grant

• Current Assignee: Wuxi Hisky Medical Technologies Co., Ltd.
• Original Assignee: Beijing Sonicexpert Medical Technology Co., Ltd., Wuxi Healthcare Medical Technology Co., LTD
• Inventors: Shao, Jinhua, Sun, Jin, Duan, Houli
• Granted Patent: US 9,554,771 B2
• Time in Patent Office: Days
• US Class Current: 600/438
• CPC Class Codes: A61B 5/4869 Determining body composition
• CPC Class Codes: A61B 6/487 involving fluoroscopy
• CPC Class Codes: A61B 8/4218 characterised by articulated arms
• CPC Class Codes: A61B 8/4245 involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 8/429 characterised by determining or monitoring the contact between the transducer and the tissue
• CPC Class Codes: A61B 8/4405 Device being mounted on a trolley
• CPC Class Codes: A61B 8/4416 related to combined acquisition of different diagnostic modalities, e.g. combination of ultrasound and X-ray acquisitions
• CPC Class Codes: A61B 8/4477 using several separate ultrasound transducers or probes
• CPC Class Codes: A61B 8/461 Displaying means of special interest
• CPC Class Codes: A61B 8/467 characterised by special input means
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: A61B 8/485 involving measuring strain or elastic properties
• CPC Class Codes: A61B 8/486 involving arbitrary m-mode
• CPC Class Codes: A61B 8/5207 involving processing of raw data to produce diagnostic data, e.g. for generating an image reconstruction G06T11/00
• CPC Class Codes: A61B 8/5223 for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012
• CPC Class Codes: A61B 8/54 Control of the diagnostic device
• CPC Class Codes: G01N 2291/02466 Biological material, e.g. blood
• CPC Class Codes: G01N 2291/02827 Elastic parameters, strength or force
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G16H 50/30 : for calculating health indices; for individual health risk assessment

Abstract

A method for nondestructively detecting an elasticity of a viscoelastic medium and a device for nondestructively detecting an elasticity of a viscoelastic medium are provided. The method comprises steps of: a) driving an ultrasonic transducer probe with a low-frequency vibration by a vibrator so as to produce an elastic wave to be propagated in the viscoelastic medium, transmitting an ultrasonic wave to the viscoelastic medium by the ultrasonic transducer probe, and collecting an ultrasonic echo returned from the viscoelastic medium; b) selecting an effective ultrasonic echo from the ultrasonic echo according to a duration of the low-frequency vibration and physical parameters of the viscoelastic medium; c) calculating a propagation velocity of the elastic wave in the viscoelastic medium according to the effective ultrasonic echo; and d) calculating the elasticity of the viscoelastic medium according to the propagation velocity of the elastic wave.

Claims

1. A method for detecting an elasticity of a viscoelastic medium, comprising steps of:

a) driving an ultrasonic transducer probe with a low-frequency vibration by a vibrator so as to produce an elastic wave to be propagated in the viscoelastic medium, transmitting an ultrasonic wave to the viscoelastic medium by the ultrasonic transducer probe at a pulse repetition frequency of about 100 Hz-100000 Hz, and collecting an ultrasonic echo returned from the viscoelastic medium;

b) selecting an effective ultrasonic echo from the ultrasonic echo according to a duration of the low-frequency vibration and physical parameters of the viscoelastic medium, wherein the ultrasonic transducer probe is static and the elastic wave is propagated in the viscoelastic medium at a moment corresponding to the effective ultrasonic echo;

c) calculating a propagation velocity of the elastic wave in the viscoelastic medium according to the effective ultrasonic echo; and

d) calculating the elasticity of the viscoelastic medium according to the propagation velocity of the elastic wave.

2. The method according to claim 1, wherein the step b) comprises:

assuming the duration of the low-frequency vibration is T, and the ultrasonic transducer probe is static after T+Δ

T since the vibration starts,

a serial number N_seiect of an effective ultrasonic signal scanning line satisfying;

N_select≧

ceiling((T+Δ

T)×

F_high),

where ceiling(.) is a ceiling rounding function, F_high is a pulse repetition frequency of transmitting an ultrasonic signal and is within a range from 100 Hz to 100000 Hz, and the ultrasonic signal scanning line is a collected ultrasonic echo corresponding to an transmitted ultrasonic pulse;

assuming a thickness of the viscoelastic medium is D₁, and a lower limit of the propagation velocity of the elastic wave in the viscoelastic medium determined according to an estimated hardness range and an estimated density of the viscoelastic medium is V_s¹, when the elastic wave is still propagated in the viscoelastic medium, the serial number N_select of the effective ultrasonic signal scanning line satisfying;

N_select<

ceiling((D₁/V_s¹+T)×

F_high);

when Δ

T is less than D₁/V_s¹, by combining above two formulae, N_select satisfying;

ceiling((T+Δ

T)×

F_high)≦

N_select≦

ceiling((D₁/V_s¹+T)×

F_high); and

when Δ

T is not less than D₁/V_s¹, if an elastic intermediate medium with a thickness of D₂ and a first hardness is added between the ultrasonic transducer probe and the viscoelastic medium so that Δ

T<

D₁/V_s¹+D₂/V_s², where V_s² is a propagation velocity of the elastic wave in the elastic intermediate medium, then the serial number N_select of the effective ultrasonic signal scanning line satisfying;

ceiling((T+Δ

T)×

F_high)≦

N_select≦

ceiling((D₂/V_s²+D₁/V_s¹+T)×

F_high).

3. The method according to claim 1, wherein a vibration frequency f of the low-frequency vibration is between about 0.5 Hz and about 3000 Hz, and the duration of the low-frequency vibration is between about 1/2f and about 40/f.

4. The method according to claim 1, further comprising:

acquiring a M-mode ultrasonograph of the viscoelastic medium and selecting a position to detect the elasticity of the viscoelastic medium according to the M-mode ultrasonograph;

or

using a two-dimensional or three-dimensional ultrasonic image of the viscoelastic medium to select a position to detect the elasticity of the viscoelastic medium.

5. The method according to claim 1, further comprising:

detecting a pressure applied to the viscoelastic medium by the ultrasonic transducer probe;

determining whether the pressure satisfies a preset condition; and

if so, detecting the elasticity of the viscoelastic medium.

6. The method according to claim 1, further comprising:

detecting a verticality between the ultrasonic transducer probe and the viscoelastic medium;

detecting whether the verticality satisfies a preset condition; and

if yes, detecting the elasticity of the viscoelastic medium.

7. A device for detecting an elasticity of a viscoelastic medium, comprising:

a vibrator producing a low-frequency vibration;

an ultrasonic transducer probe driven by the vibrator with the low-frequency vibration so as to produce an elastic wave to be propagated in the viscoelastic medium; and

a control apparatus connected with the ultrasonic transducer probe and the vibrator respectively, and configured to control the ultrasonic transducer probe to transmit an ultrasonic wave to the viscoelastic medium and to collect an ultrasonic echo returned from the viscoelastic medium, to select an effective ultrasonic echo from the ultrasonic echo according to a duration of the low-frequency vibration and physical parameters of the viscoelastic medium, and to calculate a propagation velocity of the elastic wave in the viscoelastic medium according to the effective ultrasonic echo to calculate the elasticity of the viscoelastic medium, wherein the ultrasonic transducer probe is static and the elastic wave is propagated in the viscoelastic medium at a moment corresponding to the effective ultrasonic echo.

8. The device according to claim 7, wherein the control apparatus comprises one of a computer, a microprocessor and a microcontroller, as well as an ultrasonic transmitting and receiving circuit connected with the one of the computer, the microprocessor and the microcontroller through a communication interface.

9. The device according to claim 7, wherein the control apparatus comprises a triggering key implemented by a hardware or a software for starting to detect the elasticity of the viscoelastic medium.

10. The device according to claim 7, further comprising a pressure sensor array mounted between and contacted with the ultrasonic transducer probe and the vibrator, wherein the control apparatus further comprises a pressure signal collecting circuit connected with one of a computer, a microprocessor and a microcontroller through a communication interface.

11. The device according to claim 10, wherein the control apparatus is further configured to start to detect the elasticity of the viscoelastic medium according to a pressure applied to the viscoelastic medium.

12. The device according to claim 10, wherein the control apparatus is further configured to start to detect the elasticity of the viscoelastic medium according to a verticality between the ultrasonic transducer probe and the viscoelastic medium.

13. The device according to claim 7, further comprising an ultrasonic diagnostic equipment connected with the control apparatus for selecting a position to detect the elasticity of the viscoelastic medium.

14. The device according to claim 7, further comprising a state indicating device for indicating a current working state of the device.

15. The device according to claim 7, further comprising a mechanical arm for supporting an ultrasonic probe consisting of the ultrasonic transducer probe and the vibrator.