Measuring tissue mobility

• US 7,201,721 B2
• Filed: 12/02/2004
• Issued: 04/10/2007
• Est. Priority Date: 06/03/2002
• Status: Active Grant

• Current Assignee: Polmosonix Pty., Ltd., Respiri (Israel) Ltd.
• Original Assignee: PulmoSonix Pty., Ltd. (Spenda Ltd.)
• Inventors: Wilkinson, Malcolm Howard
• Primary Examiner(s): Hindenburg; Max F.
• Assistant Examiner(s): SZMAL, BRIAN SCOTT
• Application Number:
  US11/001,959
• Publication Number:
  US 20050085747A1
• Time in Patent Office: 859 Days
• Field of Search: 600/552, 600/438, 600/442, 600/443, 600/437, 600/587, 600/553, 73597-599
• US Class Current: 600/552
• CPC Class Codes: A61B 5/0051 by applying vibrations
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/442 Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface

Abstract

A method of measuring tissue mobility includes applying an oscillatory force to a region of tissue and measuring the velocity with which the tissue moves in response to the applied force. Tissue mobility is then determined by a ratio of the tissue velocity to the applied force.

Claims

1. A method of measuring tissue mobility comprising the steps of:

(a) applying an oscillatory force to a region of tissue using a vibrating mass having an oscillatory velocity u_m; and

(b) determining an oscillatory velocity u_t with which the tissue moves in response to the applied force;

wherein tissue mobility is determined by a ratio of the tissue velocity u_t to the velocity of the vibrating mass, u_m.

2. A method of measuring tissue mobility according to claim 1 wherein the frequency of the oscillatory force is varied over a period of time.

3. A method of measuring tissue mobility according to claim 1 wherein the oscillatory force corresponds to pseudo-random noise or white noise.

4. A method of measuring tissue mobility according to claim 1 wherein the force is applied using a vibrating mass which is set in motion, with oscillatory velocity u_m, using an electromagnetic driver which is coupled to the tissue via a coupling device.

5. A method of measuring tissue mobility according to claim 4, wherein the mobility of the tissue, z_t(ƒ

) is given by;

$z_t<br><br>\left(f\right)=\frac{1}{2<br><br>\mathrm{\pi <br><br>}<br><br><br><br>f<br><br>\left\{\frac{u_m}{u_t}<br><br>m_v+m_f\right\}}$

where m_ν

is the mass of the vibrating mass; and

m_ƒ

is the mass of the coupling device.

6. A method of measuring tissue mobility according to claim 1 wherein the velocity at which the tissue moves in response to the applied force is determined at a location which is spatially distinct from the region of tissue to which the force is applied.

7. A method of measuring tissue mobility according to claim 1 comprising the additional step of providing a visual representation of the velocity at which the tissue moves in response to the applied force.

8. Apparatus for measuring mobility of a region of tissue comprising:

(a) a force generator driving a vibrating mass with an oscillating velocity u_t for application of an oscillatory force to a region of tissue;

(b) a tissue velocity determiner producing a tissue velocity signal u_t which corresponds to the velocity with which the tissue moves in response to the applied oscillatory force; and

(c) a processor processing the tissue velocity signal u_t and the vibrating mass velocity signal u_m;

wherein the tissue'"'"'s mobility is determined using a ratio of the tissue velocity u_t to the velocity of the vibrating mass, u_m.

9. Apparatus for measuring tissue mobility according to claim 8 wherein the force generator is a vibrating mass which is set in motion with an oscillatory velocity u_m, using an electromagnetic driver which is coupled to the tissue via a coupling device.

10. Apparatus for measuring tissue mobility according to claim 9, wherein the mobility of the tissue, z_t(ƒ

) at a frequency ƒ

is given by;

$z_t<br><br>\left(f\right)=\frac{1}{2<br><br>\mathrm{\pi <br><br>}<br><br><br><br>f<br><br>\left\{\frac{u_m}{u_t}<br><br>m_v+m_f\right\}}$

where;

m_ν

is the mass of the vibrating mass; and

m_ƒ

is the mass of the coupling device.

11. Apparatus for measuring tissue mobility according to claim 8 wherein the force generator applies an oscillatory force to a region of tissue which is spatially distinct from the location of the tissue velocity determining means.

12. Apparatus for measuring tissue mobility according to claim 10 further comprising a display device for displaying a representation of mobility of the region of tissue, wherein the representation of mobility includes a graph of mobility versus frequency.